Sugar Crystal Growth

For our holiday homework, we had to grow sugar crystals! :)

Sugar crystals are grown based on the concept that solubility of a liquid decreases when its temperature decreases.

Materials:
1 pot
1 measuring cup
1 cup of water
3 cups of table sugar
2 glasses (I prefer glasses because it is transparent and you can look through to see how the crystals are growing)
*Note: always have >1 setup in case one fails-that's why I use 2 glasses
2 pencils/knifes
Two pieces of string (should be able to be tied around the pencil/knife and lowered into glass almost but not quite touching bottom of jar-about 1-2cm leeway)
One tray filled with tray (used as a moat to keep ants and other insects from disturbing your setup)


Step 1: Boil a pot of one cup of water.
Step 2: When it has finished boiling, pour in all 3 cups of sugar.
Step 3: Put the 2 glasses on the tray. (Ensure the tray is placed in a place with minimum dust and chance of disturbance)
Step 4: Pour it into the 2 glasses (*BEWARE IT'S HOT)
Step 5: Tie the string to the pencil and slowly lower it in. Ensure string is not touching any part of the glass.
Step 6: Wait. After a week or so, your crystal should grow!

Reference: http://www.kidzworld.com/article/26598-make-your-own-crystals



When the water is boiled, its solubility increases. Hence all the sugar can dissolve in it. However when it cools down its solubility decreases allowing less sugar to dissolve. Hence the sugar that can no longer dissolve crystallises on the string and voila, you have a sugar crystal.

After a week, my crystals are growing both on the string and on the surface of the water :O
But why?

After finding out from my friends, it is better to put a small piece of rock sugar on your string first. The sugar in the water will then gather around that piece of rock sugar. Else there is a high chance it won't grow on your string. That is something I need to take note of in the future.

(I'm not too sure whether that is allowed though)

Try this out at home! You can eat it after it's finished, or even add food colouring to decorate it!

That's all for now!

Term 2 Week 3

This week we learnt about the states of matter with regards to heat as well as how to explain their conversions with kinetic particle theory. We also learnt how to interpret graphs regarding heat gain or loss over time.


Internal energy is the combination of the total kinetic and potential energy of particles in a body.
Kinetic energy is due to the vibration and translation of particles. Temperature is a measure of the amount of kinetic energy for a certain amount of an object or body.
Potential energy is stored like a spring-the attractive forces between particles are stretched and compressed accordingly.

Kinetic particle theory explanations-model answers:

In explaining a change in state with kinetic particle theory there are 4 sections:

• describe the amount of a type of energy lost
• movement and arrangement of particles
• threshold as to the forces between the individual particles
• description of final state

Melting

•When a solid is heated, the particles absorb heat energy

•The particles gain kinetic energy

•Start to vibrate faster

•And move further apart

•At melting point, enough potential energy to overcome the strong forces of attraction

•The particles start to break away from one another

•solid becomes a liquid

•At the liquid state, the particles start to roll and slide over one another

Freezing

•When a liquid is cooled, the particles lose heat energy

•The particles lose kinetic energy

•slide and roll less vigorously

•At freezing point, particles have not enough potential energy  to overcome the strong forces of attraction holding them together.

•particles start to come together in a regular arrangement and the liquid becomes a solid.

Boiling

•When a liquid is heated, the particles absorb heat energy

•The particles gain kinetic energy

•Slide over each other more rapidly

•the particles gain sufficient potential energy to overcome the attractive forces between the particles

•And move far apart rapidly in all directions

•Forming a gas

Term 2 Week 4

This week we learnt about the elements of the periodic table.

Firstly, what are elements? Element comes from the latin word elementum which means principle, rudimentary. Element thus implies something basic. In chemistry, any substance than cannot be broken down into further simpler things is an element.

Some element components of substances:

Water: Hydrogen, oxygen
Ammonia: Nitrogen, hydrogen
Fructose: Carbon, hydrogen, oxygen
Deoxyribosenucleic Acid: Carbon, nitrogen, oxygen, phosphorus
Polyvinyl Chloride (PVC): Carbon, hydrogen, chloride
Fat: Hydrogen, carbon, oxygen
Paracetamol (Panadol): Carbon, hydrogen, nitric oxide (a compound of nitrogen and oxygen)
Chlorophyll: Carbon, hydrogen, oxygen, nitrogen, magnesium
Protein: Carbon, hydrogen, oxygen, nitrogen, R group elements (polypetide amino acids)

In the human body, there are usually:
Oxygen from air and water
Carbon from carbohydrates and as a byproduct of cellular respiration
Nitrogen from the air, cured meats and plants
Calcium from milk, fish, vegetables
Phosphorus from food like red meat and poultry, dried milk, dairy products, bran, seeds
Iron from red meat
Magnesium from vegetable and whole grains
Potassium from leafy vegetables and beans
Zinc from seafood

Different elements were found at different times. (13 in the antiquity to middle ages, 21 in the middle ages etc)

Some of the elements took longer to discover as they either too unstable to be isolated as a single element, had limited uses at the time, or were rare (e.g. francium).

Metals are elements with metallic properties, properties such as:
Good electrical conductivity (for solids)
Shiny
Strong
Hard
Malleable (can be bent)
Ductile (can be streched)
Good heat conductivity

All the elements on the periodic table are metals except:

Hydrogen, carbon, nitrogen, oxygen, fluorine, neon, phosphorus, sulfur, chlorine, argon, selenium, bromine. krypton, iodine, xenon, radon

*GENERAL NOTE: SOME OF THESE POSTS MAY NOT BE CONCLUSIVE AS THE REST IS CONTINUED ON THE NEXT WEEK

Term 2 Week 2

(Sorry I am writing a lot of these posts many weeks later as I have been very busy so they may have slightly less details)

This week, we learnt about how to accurately describing the molecules in the three states of matter in terms of the attractive forces between the molecules, the distance between the molecules and the speed they move. We also learnt how to describe them using kinetic particle theory, including the change of state. We learnt the relationship between the speed of molecules and their temperature, as well as learning about plasma and bose-einstein condensate, their properties, and their conversions into the other states of matter (kinetic particle theory too).

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There are 4 main characteristics of states of matter we look at here:
-shape
affected by arrangement of particles
-volume
affected by forces between particles and distance between particles
-compressibility
distance between particles
-whether brownian motion of a small particle can take place in it
affected by movement of particles


Solids:

Shape: fixed-particles closely packed together in fixed, regular pattern, occupying little space
Volume: fixed-particles vibrate about fixed positions and are held in position by very strong attractive forces
Compressibility: cannot be compressed as particles are too close together
Brownian motion-cannot take place

Liquids:

Shape: not fixed-particles slide past one another, free to move but confined within the vessel containing it
Volume: fixed-particles though they can slide past each other are still held together by attractive forces
Compressibility: cannot be compressed as particles are close together
Brownian motion-can take place

Gas:

Shape: not fixed-particles scattered freely throughout vessel in irregular pattern, occupying a lot of space
Volume: not fixed-particles have large distances between each other and can be squeezed closer together
Compressibility: can be compressed as particles are far apart
Brownian motion-can take place

We also learnt about two other states of matter-plasma and bose-einstein condensate.

Plasma is a state of matter consisting of free electrons and ions. These particles, unlike the other 3 states, can be controlled (e.g. plasma ball) using electrical and magnetic signals.

A plasma ball is a toy that is meant to mimic a tesla coil at a smaller scale. There is a coil of wires inside that have high frequency electrons vibrating. This vibration is so vigorous that the electrons are ripped off the atoms-forming plasma.

There are a few tricks you can do with a plasma ball.

The first is to put your hand on the plasma ball. A line of electricity similar to lightning will connect the core and the part of the glass your hand is touching. (You won't get electrocuted)

Placing a fluorescent light tube close to the plasma ball will ignite the light tube.

If you have two people, let one touch the plasma ball and the other hold a fluorescent tube. Holding the tube near to the person will cause it to light up as well.

In fluorescent lamps, electricity charges up mercury gas charging and exciting the atoms within-making the plasma emit light.

There is also Bose-Einstein condensate.

Firstly, all particles can be either bosons or fermions. All particles have a property known as spin, with fermions and bosons having fraction and whole number spins respectively. Thus fermions can be distinguished while bosons cannot. Bose-Einstein condensate only applies for bosons.

In Bose-Einstein condensate, there is no friction at all. Temperatures are extremely low (approaching 0) which makes these particles tend to form wave patterns.

Disclaimer: I told this to my father and he said the part about Bose-Einstein condensate is COMPLETELY WRONG! I am still not very sure what is right but Mr Tan you may want the teachers to confirm whether these facts are correct (he told me the wave thing is a COMPLETELY DIFFERENT CONCEPT from BSE)

Term 2 Week 1

A New Term Begins...


This term, we did a lot of really fun and new stuff! Finally, on to some real Science! (After a short revision of last term's topics during the first lesson...)

This week, we learnt about Kinetic Particle Theory.

(a.k.a a big phrase to say that atoms are in continuous and random motion)

At first glance, the definition seems rather insignificant. Okay, they are constantly moving in no preset direction. What was so interesting, I thought.

Only later did I find out that the interesting part was the derivation of the theory.

Atoms are the smallest things on earth. At 10^-19m long (0.1-0.5 nanometres) they could not be seen even with the most powerful of the microscopes in the days when the theory was discovered. So during the time when we didn't have scanneling tunneling microscopes (which were only invented quite late and can see atoms), how did they even know about this theory?

The answer-brownian motion and diffusion.

Brownian motion affects everything, even us. Just that the effects on us are too small to be seen. Brownian motion is the resultant effect when we are bombarded by smaller particles. When we look through a microscope at dust particles (no not clumps of dirt but the much finer grains-but still can be seen through a normal microscope in those days), they are moving continuously and randomly. Even though there is no wind or other external force acting on them. So, how do they move?

This is because air particles, invisible to us, are constantly bombarding the dust particle at high speeds, thus resulting in the dust particle to move erratically. We can be sure that it is because of the air particles' bombardment because when the temperature rises, the motion of the dust particle increases because the air particles themselves move faster when they have more heat and thus kinetic energy.


Diffusion is the spreading of a substance throughout a fluid. When a drop of food colouring is dropped inside a cup of water, it quickly spreads throughout the liquid. This is because of kinetic particle theory. The particles of the substance move quickly, continuously and randomly thus spread throughout the water quickly yet without any identifiable pattern.

Here is a video on kinetic particle theory.

Term 1 Week 8

This week-summary week; we basically went over everything done in the past. (Also a little bit of new stuff)

(I feel like just putting the ppt here but that would be laziness)

Accuracy VS Precision

To make things clearer and easier I'll use a bulls-eye analogy

Accuracy-how close the darts are to the centre

Precision-how close the darts are to each other

Also known as: random error VS systematic error (respectively)

Length measurements:

Measuring tape and ruler-1 dp (cm)

Vernier caliper-2 dp (cm)

Micrometer screw gauge-3 dp (cm)/2 dp(mm)

Volume measurements:

Measuring cylinder-0.5 cm cube

Burette-0.05 cm cube

Pipette and volumetric flask-fixed volume

Meniscus-lowest/highest point of water level when viewed

For usual measurements e.g. measuring cylinder read concave (lower) meniscus 

For mercury thermometer read convex (higher) meniscus

Area measurement: irregular figures:

Divide area into grid.

If square is fully filled, count it.

If square is more than half filled, count it.

If square is less than half filled, do not count it.

The smaller the squares, the greater the accuracy.

Measuring time:

Stopwatch:

Digital and analogue-digital more accurate measuring 2dp; analogue can only measure 1dp

However for stopwatch 2nd dp should not be counted because of human error-unless it is not a human starting and stopping the stopwatch

Human error=0.2-0.3s

Ticker-tape timer:

Electrical device using oscillations of a steel strip to measure short time intervals

Steel strip vibrates 50 times a second and makes 50 dots a second on a paper tape being pulled past it

Distance between every two dots=distance of 0.02 seconds of motion



For pendulum:

Fudicial line-an imaginary line in the centre of each swing
Oscillation-amount of time for pendulum to pass by fudicial line twice
Period-time for one oscillation

That's all for this term! See you next time!

Term 1 Week 7

This week, we played around with two main things-the vernier caliper and micrometer screw gauge.

Such complicated names.........

Scared me at first.

Lucky, they are just two other measuring instruments. The normal meter ruler can measure up to 0.1cm. The vernier caliper can measure up to 0.01 cm. The micrometer screw gauge can measure up to 0.001 cm (or 0.01 mm)




...so much more elaborate than a ruler. Both of them take quite a long process to measure when you compare with a ruler...

(I'm too lazy to explain the whole thing so here's a video on how both work)



I was wondering how to measure huge objects yet with great precision. Especially for things like rockets that require extraordinary precision. Do they have a giant vernier caliper...

Term 1 Week 6

This week, we learnt about indices/powers, especially of 10.

Why do we see these appearing in Science? Some measurements in Science are either very very big or very very small. Thus for certain things you will get measurements such as 70000000000000000 light years or 0.0000000000000000576mm for things such as distance between planets or size of atoms respectively (not exact measurements, just examples). However adding lots of zeros may result in errors because having 100 zeros and 101 zeros is a BIG difference in reality but in writing it is only one extra zero which some careless people might not notice. Secondly it is extremely tedious to write, again possibly resulting in error as well as wasting time. Can you imagine writing 100 zeros in each number sentence you write? Thus people have started to use powers of 10 to express the numbers in standard form.

10^0=1
10^1=10
10^2=100
10^3=1000

These are examples of powers of 10 (which if you do not already know) are numbers whereby 10 multiplies itself a few times such as 10^3 means 10 multiplied by itself 2 more times which is 1000. This also works for other numbers besides 10. Fortunately for powers of 10 whenever you multiply by 10 you just need to add a zero onto the original value making multiplying by 10 very east; to find ten to the power of x you just take a 1 and put x number of zeros behind it.

An example of a number in standard form: 1.287*10^6. A number in standard form is always a value from 1 to 9.999999999999... multiplied by a power of 10. The exponent can be positive or negative (but not a decimal or fraction). For example, 5678350000000=5.67835*10^12.

In this way, doing multiplication and division is also easier; even addition and subtraction.

Examples:

For multiplication:

(5.67*10^4)(3.91*10^7)
=(5.67*3.91)(10^4*10^7)
=22.1697*10^11---------4+7=11 so 11 is the exponent for the result; only works for powers of 10
=2.21697*10^11---------remember to convert the coefficient to a single digit number (not including dp)

For division:

(5.67*10^7)/(3.91*10^4)
~1.45*10^3--------------note how similarly the exponents can be subtracted to get the resultant exponent

For addition:

(5.67*10^7)+(3.91*10^4)
=(5.67*10^7)+(0.00391*10^7)-----raise smaller exponent to larger one and change coefficient accordingly
=5.67391*10^7

For subtraction:

(5.67*10^7)-(3.91*10^4)
=(5.67*10^7)-(0.00391*10^7)
=5.66609*10^7

Remember that all these operations can also be done for negative exponents.


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However, to some people these numbers are meaningless. They don't really see much difference between 10^10 and 10^11. Thus we have prefixes.

Prefixes in English are phrases that can be added to the front of certain words that always change the meaning a certain way. Prefixes in Science work the same way, in a way multiplying the current value of that number by a certain power of 10. Some prefixes-kilo=10^3, mega=10^6, giga=10^9, milli=10^-3, nano=10^-9... the list goes on. The distance between most prefixes are multiples of 10^3 except hecto, deka, deci and centi, which are near one. Each of these prefixes has its own symbol.




58400000 grams (g)
=5.84*10^7 grams (g)
=58.4 Megagrams

0.00000764 metres (m)
=7.64*10^-6 metres (m)
=7.64 micrometres


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The next lesson, we went to the Science lab. We did an experiment, but a rather unexciting one-timing pendulums.

We took a retort stand, tied a string to a weight then clamped the string tightly. We then displaced the weight at an angle then let it swing freely for a minute while counting the number of oscillations. Finally we divide the time by the number of oscillations to find the period, or the time for one oscillation. We then repeated the steps for different lengths of string.

After the experiment, our teacher Mr Tan explained to us A LOT of things that we had to take note during the experiment.

Firstly, the angle could not be too big. Otherwise the swinging could get rather erratic.

Secondly, we had to look at the pendulum from in front not from the side. Basically you couldn't observe it from the angle whereby it swings towards you. This is because the period is defined by the time between every two times it crosses the fudicial line which is basically the centre point of the swing. If you view it from the side then you couldn't really see when it actually crossed the fudicial line.

Thirdly you couldn't start the timer immediately after the pendulum first crossed the fudicial line! You had to wait a few swings before starting the timer so as to let the pendulum stabilise.

The hardest part of the experiment was probably to measure and tie the weight to the string. We had to either let more string or tie more string around the weight to increase and decrease the length of string respectively. However at times it would be not tight enough making the weight almost fall out! Thus we would have to retie the whole thing making it quite a tedious process. It also pretty hard to measure the string properly with the ruler, and we did not know where to start measuring because part of the string was inside the clamp!


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That week, we had home-based learning, where we had to sit at home and use iVLE (our school e-learning platform) to listen to tutorials. Not as fun as learning in school...

Anyway, we learnt about mass, weight and density. (And a bit about gravity)

First, some definitions:

Mass-amount of substance in an object-measured in grams

Weight-force exerted by one object onto another due to gravity-measured in Newtons

*Note the difference between mass and weight-they are often confused

Density=mass/volume-can be considered as the concentration of substance inside the object for any specific volume

Gravitational field=a region whereby an object is affected by the force of gravity

(I can't define gravity yet though, sorry)

We also learnt that human reaction error time is from 0.2 to 0.3 seconds. I was thinking "so much?" Our NAPFA can change from a gold to a silver just because of a few milliseconds! It shocked me! Sadly there is no fixed error time so you can't like subtract a certain amount from your timing to get the real amount... if only there were some affordable equipment that can be more accurate...

Term 1 Week 5

This week, we have been learning physical quantities and units. If you have a certain amount of substance, or any other thing such as length, volume, time, how are you going to represent them? Furthermore, how are you going to ensure that the way you represent that particular amount of substance/time etc is the same universally? Thus we need units. Units are used firstly to tell the viewer what is being measured, then how much of it. Examples are cm, kg etc. These units are universal so that if one scientist in Singapore says that this substance is 100kg, a scientist in America knows exactly what him or her is talking about. In the past, we had different units across the globe thus sharing information was rather difficult. Furthermore the measurement system was much more complicated. The difference in magnitude between units was quite random, for example from one unit to the next would be *6, then *22 to the next, especially when measuring volume. This made conversion very difficult. Nowadays, out units are mostly if not all in increments of powers of 10 which makes conversion much easier since you only had to add or subtract zeros. Till this day, some measurements such as length are still slightly different across the globe, with the main two scales being cm and inches which are not related in increments of powers of 10.

Base quantities-mass (kg), length (m), time (s), current (A), temperature (K), amount of substance (mol), light intensity (cd) which stand for kilograms, metres, seconds, amperes, kelvin, moles and candelas respectively. These base quantities are all the quantities that are not derived, meaning that they are not a product or quotient of two other quantities. Examples of non base quantities are Newtons, speed, acceleration etc which are measured in kg/m/s^2, m/s and m/s^2 respectively. These are all SI units, the set of units recognised worldwide (note: not including inches) and are the main scale used when measuring objects.

Term 1 Week 4

Week 4-has been a bit of a recap of what we did in primary school...

Back to square 1...

First of all, we did quite a bit of graph work; relearning how to draw graphs after forgetting everything during our holidays (just joking). We were told that we need to utilise the graph paper as much as possible and not draw one super small graph; to increase the size of each spacing between sections so as to be able to use at least three-quarters of the graph paper. This proved to be quite a challenge for me as sometimes a certain value for each spacing will be just too large and half that would be too small, so I would have to use something in the middle and end up getting decimals for the spacings. This made it even harder to mark the measurements as then I would start to need to in my mind cut up each of the individual squares into smaller parts...I just felt it needed to be precise! (OCD working up) We also had to start from something more than 0 for some graphs-something I found rather difficult as well, as in how to represent it clearly since the graph had two axes. For a graph starting from 0, you just needed to put a 0 at the intersection--but for a graph not starting from 0, the numbers the two axes are starting on are usually different--how do you clearly represent that in such a small space?

We also learnt more about what graphs are and why they are used in the first place instead of charts and tables. Graphs imply a kind of cause and effect relationship, meaning the independent variable (on x, or horizontal, axis) affects the dependent variable (on y, or vertical, axis). Charts and tables are usually just used to display results whereby no relationship between the two variables are established (e.g. fruits secondary school pupils like; you can't have a cause and effect relationship for that!).

Normally, graphs are drawn using either best-fit lines or best-fit curves. Even though a lot of data changes in a linear way, the data points do not usually form a perfect straight line (e.g. you probably won't get 10 deg. Celsius then 20 deg. Celsisus then 30 and so on; you'l probably get something like 11 then 23 then 36 then 45 then 59...), thus a best-fit line is used to get a kind of "average" of the data points; a more linear representation of the data. A best-fit curve, on the other hand, is used when the data is not meant to change linearly/changes linearly up to a certain point before not changing at all (e.g. boiling water), since even though a best-fit line would get roughly the mean, it will be quite far from most of the data points and thus not accurate. Best-fit curves are usually drawn with a flexi-ruler, which is a tool that people use to draw curved lines. (It's quite fun to play with! You should try it!)

The problem about flexi-rulers though is that they sometimes get a bit stiff and deviate from the curve, making the curve rather imperfect. And sometimes you don't know how the curve should look like in between two points, like whether to use a rather gradual curve or instead have a steep drop followed by an almost straight line.

Flexible, useful and sold at only $4.80! (At least at Hwa Chong bookshop)

The next lesson, we learnt about the scientific method (which we also conveniently forgot during the holidays). It consists of the observation, question, hypothesis, method, result and conclusion. This scientific method is a universal process used by scientists around the globe when they do their experiments. Frankly, in my opinion, the result and conclusion are pretty much the same, as well as the observation and question; they are a bit redundant. And the steps for the scientific method are pretty much obvious. What I still don't really understand is, what is the hypothesis for? It is basically a wild guess at what the result will be (if it's not a guess you're probably doing an experiment that your teacher asked you that you already know the answer to-then the experiment is pretty much useless). Some people/worksheets/websites will tell you something like "if your hypothesis is wrong, redo your experiment" or something of that sort. I feel that sometimes making a hypothesis will as a result make you do a biased experiment as you want to get that hypothesis. For example, in primary school, our classmates and I didn't know that friction was not dependent on surface area, so when we did the experiment with the spring balance, we would unconsciously change the amount of force we used as we were not getting the results that we wanted. Some people say that making a hypothesis is so as to have a basis on what you will be answering, but that is answered in the aim, not the hypothesis.

Term 1 Week 3

Mr Tan does not come (he told us beforehand) for the whole week. One of our Science lessons is turned to English and the other we have a relief teacher. The relief teacher just gave us a worksheet and told us to complete it; nothing particularly out of the ordinary. Conclusion: Not much Science learning today. But...

We have just learnt about our Independent Studies subject. All the marks for this subject are based on a Project Competition (Gulp). If we don't get a C6 for this we can't be promoted to Secondary 2, meaning once you're project goes bust, you're over! My group members are Tan Zi Yuan, Kyaw Khant Zaw and Xu Ziqi. For the Project Competition, there are 12 categories, 4 of which Secondary 1 students are not allowed to do as we supposedly do not have good enough research skills yet. The categories are: Cat 1-experimental, Cat 2-Non-experimental, Cat 3-Inventions, Cat 4-Resource Development, Cat 5-Creative Arts, Cat 6-Language Arts (English), Cat 7-Language Arts (Chinese), Cat 8-Service Learning, Cat 9-Mathematics, Cat 10-InfoComm, Cat 11-Future Trends and Cat 12-S.T.E.M (something to do with engineering Science). We are not allowed to do cats 1,2,8 and 12. After sitting for the assembly talks for all the different categories available to us, we finally decided on Cat 3, as the only ones we were actually interested in were cats 3,4 and 11. For resource development, we felt that it would be too simple and useless, thus quickly discarded the idea. For Future Trends, we knew that we would have to tackle a big topic to get a good mark, and we felt that we had no right to be debating problems that others had and have been debating for the last few decades or so. 

After brainstorming, one of our group members (Xu Ziqi) thought of an idea. People often face the problem whereby they mix up their drink bottles/cans/cups among themselves and refuse to drink each other's drinks. To solve this problem, we thought of using acrylic resin/latex (material used for scratch cards, e.g. in lucky draws) and paste it on the cap for people to scratch their initials/a symbol representing themselves so as to differentiate their drinks between themselves. After some research,we found that this kind of material was easily and cheaply available and for sale and could be painted/pasted on a surface.

For our design to work, however, we first needed to test the material for its durability and how it reacts when exposed to conditions bottles/cups/cans are sometimes exposed to, such as its resistance to scratching, heat, cold and wetness. Thus we designed some tests to test these factors. We also plan to do a survey to search on different people's opinions towards this problem.

After we met with our teacher mentor, we found that there was still one more step to do. We had to document our progress (Mr Tan who is both our Science teacher and IS mentor said it was something he had to do on us) as we worked on the project. He gave us "the 6 thinking hats", a step by step method to solve problems, and to use this template. Thus in future when I discuss with my group members on Google Docs I will have to copy chat to a Word Document and save it (lots of spam as well from the others). This is the only way I can think of to document our discussion.

Wonder what is in store for us in Week 4...

Personal Work Samples

Sorry for the poor resolution

Plasma ball demonstration by Mr Tan

Making the compound copper sulphate through heating-it turns blue first then bursts into flames!!!

This is the alcohol question I have been talking about. This signifies one of the first times in my life that I have done independent research and I find it very fulfilling. It was also very fun to think out of the box. This time, my parents had to tell me to take the initiative to search for the answer. Having this experience, I will do it on my own initiative without need of reminder.

Reflections on Science Experiences

Component 3: Reflections on Science Experiences

These experiences can include laboratory sessions, fieldwork, excursions, sabbatical courses or any Science related activities.

Details of Activity

Term: 1/2

Name of Activity: CHAOS competition viewing

Objective of Activity: CHAOS is a competition whereby teams of students from different schools are given extremely difficult and complicated questions in mathematics, physics, chemistry and biology, and are given about a month to prepare and do research before presenting their findings or solutions in a coherent storyline to a panel of judges. These questions are very complex and unique and there is no one way to arrive at the answer. In depth research is required for every questions. Presentation skills and creativity are also tested through the acting.

Venue: Science Centre

Pictures of Activity

1. What have you learnt from the activity?

For as long as I have been in Singapore, all the competitions of every subject are extremely dull and boring, and are usually very structured-e.g. math olympiad, writing competition. This particular competition has really made me learn something applicable in real life instead of some useless head knowledge that is not practical. For example, they were tested on how to estimate the number of species on earth and something else related to mutations and gene sequences. I was truly wowed by the difficulty of the competition and the intelligence of the competitors.

http://www.science.nus.edu.sg/images//outreach/chaos/CHAOS_2014_Q.pdf

http://www.science.nus.edu.sg/images//outreach/chaos/NUS%20HIGH%20CHAOS_Team%201%202013%20-%20flattened.pdf

Click these 2 links for the questions and answers respectively. You will be shocked by the complexity of the questions that these mere secondary school students are expected to do.

2. What do you like most and least about the activity?

I liked the uniqueness and difficulty of the competition. I also liked that there was no specific answer or rubric and that it tested many different skills. It is also more relevant to real life as you learn research and presentation skills instead of for example olympiads where you are tested questions based on your own knowledge even though firstly it is not relevant to real life and secondly you can get the necessary information through other means in real life. The challenge of this competition is not knowledge alone but filtering out the correct information to use and how to present it in a systematic, creative and coherent manner.

I didn't like so much how the students were forced to act out the answers in a storyline. To me it was rather a waste of efforts of the students that did not contribute to the actual quality of the answers. One of the teams nush, did better than RI, even though I felt that there Science was much shallower. However they had more acting and that was probably the deciding factor for them to win. I feel that the rubrics should put little to no emphasis on the "storyline" which just gives another thing for the already burdened students to worry about.

3. What do you learn about your partner (if any) from doing the activity? (No partner involved)

By the way Hwa Chong clinched first!!! :)

Reflections on termly performance and growth and development in Science

I: Termly Performance
1. What is your target? (A1, A2, B3 etc.)
Ans: A1.
2. What is my plan to achieve my target?
Since my main weakness in Science is answering techniques, I will look through the different types of questions and memorise the format for each. I will also look through the concepts and clear any misconceptions.
3. For class tests/end of year exam, what are the areas that you need to improve and what concrete steps that you would take to improve.
Same as above.
II: Growth Development
1. Which parts of the lesson did you not understand?

During the lesson on Bose-Einstein condensate, I heard about bosons and fermions. I have a few questions. Why does having a whole number make it indistinguishable? What do you define as distinguishable? Why do the atoms need to be indistinguishable to become Bose-Einstein condensate? What defines something as being in the state of Bose-Einstein condensate? Our Science teacher told us that Bose-Einstein condensate had something to do with indistinguishable waves, but my father said this is A COMPLETELY DIFFERENT CONCEPT!

As for now that is about all the questions I have.

2. Where do you look for more information to help you understand the lessons better?
Ans: I usually ask my parents/teacher about the topic/question or search the internet for the answer.
For example, one of the questions in a test was "How do you heat alcohol (flammable) with a Bunsen burner so that it will not catch fire?" As I had never seen such a question before, I thought of the thistle funnel that our Science teacher had introduced to us during our lab session and also that combustion required oxygen. I thought that I could place a chemical that absorbed oxygen inside the enlarged part of the thistle funnel and then pour the alcohol inside to be heated as it would have no oxygen to combust. After asking my parents, they told me the conventional method of indirectly heating the alcohol using a water bath and Bunsen burner. They also felt that my method was incorrect as they had never heard of a thistle funnel before. After searching the internet, I found out why the alcohol caught fire even though it was not in direct contact with the flame (through the test tube)(I originally thought contact with the flame was the factor causing the alcohol to catch fire); alcohol has a flash point that will cause it to catch fire, and even and slow heating will prevent the alcohol from catching fire. I also searched for materials that can absorb oxygen. Finally, I asked my teacher, and he said that though my method is correct, the water bath is the easier and more conventional method to heat alcohol.
3. What are the different ways that you have used to solve problems on your own?
Ans: I will read up books or on the internet, as well as consult my parents/teachers/seniors/fellow classmates or anyone else who is a reliable source of information.

Issues in teaching and learning Science

1. Problems you faced in the learning of Science and how you overcome those problems?

I don't really have much problem with learning Science as most concepts are pretty easy to digest and remember but its just that I am unable to answer questions in the way markers want me too. To solve the problem I usually try and memorise the types of questions there are and the format for answering them. Occasionally I will have problems memorising certain stuff (e.g. deci, deca, periodic table) and will sometimes have some facts slip my mind but those occur rather randomly and are rather easy to get over.

2. What are the Scientific concepts that you have learnt? (State three examples)

1. Temperature is a measure of the kinetic energy in a specific body.
2. Kinetic Particle Theory tells us that all particles are in continuous and random motion.
3. Liquids and gases diffuse from an area of higher concentration to lower concentration.

3. How are these knowledge and skills useful and relevant to the real world?

It allows me to better understand scientific phenomenon going around me in the real world and helps me understand how certain things work or why they work this way.

4. What have I learnt that which is beyond my textbook/notes knowledge? (List at least 3 examples)

I have learnt about how to heat alcohol without making it combust, what is the factor that causes it to combust, and other ways to heat it up which reduce the chance of combustion.

 I also searched for different materials that absorb oxygen. This is what I found:

"The first patent for an oxygen scavenger used an alkaline solution of pyrogallic acid in an air-tight vessel.

Modern scavenger sachets use a mixture of iron powder and sodium chloride.^[7] Often activated carbon is also included as it adsorbs some other gases and many organic molecules, further preserving products and removing odors.

When an oxygen absorber is removed from its protective packaging, the moisture in the surrounding atmosphere begins to permeate into the iron particles inside of the absorber sachet. Moisture activates the iron, and it oxidizes to form iron oxide. Typically, there must be at least 65% relative humidity in the surrounding atmosphere before the rusting process can begin. To assist in the process of oxidation, sodium is added to the mixture. Sodium acts as a catalyst, or activator, causing the iron powder to be able to oxidize even with relative low humidity. As oxygen is consumed to form iron oxide the level of oxygen in the surrounding atmosphere is reduced. Absorber technology of this type may reduce the oxygen level in the surrounding atmosphere to below 0.01%.^[2][3] Complete oxidation of 1 g of iron can remove 300 cm³ of oxygen in standard conditions. Though other technologies can remove more, iron is the most useful as it does not cause odor like sulfur compounds or passivate like aluminium compounds. Many other alternatives are not food safe.^[7] The moisture requirement of iron-based scavengers makes them ineffective in moisture sensitive applications.

The performance of oxygen scavengers is affected by ambient temperature and relative humidity.^[8] Newer packaging technologies may use oxygen scavenging polymers to prevent accidental ingestion of oxygen scavengers.^[7]"

Taken from http://en.wikipedia.org/wiki/Oxygen_scavenger

From this I could see that there are indeed cheap and common materials that can be used to absorb oxygen even though my teacher and parents told me that such materials may not even exist, and even if they do, would be rare, expensive. This tells me that this is not true. Besides iron, there are also other non-ferrous materials that serve the same purpose, like citrus.

I also learnt that the true function of a thistle funnel, unlike what is said in class, is to pour liquids or reagents into narrow neck containers, not to put materials that absorb chemicals as what was said in class. (Mr Tan if you are reading this could you clarify?)

I still don't really see why my method doesn't work. These oxygen scavengers can reduce oxygen levels to below 0.01%, are cheap and are available. Why not feasible?

Uni Physics stuff-self directed and independent learning

Hello everyone,

This is just an extra page about physics stuff, and I won't be making a new page every time I update the physics section.

*CHANGE-TO TEACHERS-THIS IS MY SECTION ON SELF DIRECTED AND INDEPENDENT RESEARCH LEARNING. I SHALL BE DOING THIS PART ON PHYSICS INSTEAD OF SEARCHING FOR MANY IRRELEVANT TOPICS AND INSTEAD FOCUS ON ONE PARTICULAR TOPIC. PLEASE MARK WITH YOUR RUBRICS BASED ON THIS PAGE.

Just some clarification: Don't think anything big when you hear uni textbook; its not really that hard (some of the things are actually done in Sec 3, in fact the first chapter is devoted to estimation and the number of important digits, as well as exponentials, which is just a fancy word for expressing things in powers of 10: (calculator format), and I haven't gone that all that far yet.

My father is always telling me: many people think that physics is basically memorising a bunch of formulas. However, my father says that to do physics well one needs to understand the concepts of physics well. Though I do not see the importance of this now, I hope to in the future.

A few apologies, as this is all done in blogging format, I will be unable to insert some symbols and might need words. If you feel something is wrong with the equations or you don't understand some things, just post it in the comments.

I will probably be arranging my things in chapters.

Kinematics in one direction(=speed and acceleration)
14/1/14:
When I started my physics textbook, this is the first chapter with any real math in it. So it was quite daunting at first. The first stuff is basically the rate and speed stuff you do in primary school. The only new thing is that velocity instead of speed is used. This means that it also includes the direction and at least one of the directions must be stated as positive and negative (which makes the other the opposite).

Basically, 1D kinematics is movement in one dimension (forward and backward). There are some important equations for 1D kinematics:

v=v0+at
x=x0+v0t+1/2a(t)(square)
vsquare=(v0)square+2a(x-x0)
v(average)=(v+v0)/2

All these equations require a to be constant. For each of these equations, v is velocity, x is distance, a is acceleration and t is time. (The 0s are meant to be subscripts but I can't do that in Blogger). v without a subscript basically means that it is the velocity of an object at a designated point of time (e.g. at t1, the velocity of the object is v1 and the distance it has travelled is x1-x0 where x0 is the starting point). Normally the subscript 1 is not used unless there are two designated points (subscript 2) where there is a greater need to differentiate the two. For t however, when there is no 0, it refers to a duration of time. A specified point in time will usually always have a subscript.

I will try to put these equations into layman terms/explain them. I probably won't do very well, but I'll try my best.

Eq 1: v is v1. The time for the object to accelerate from v0 to v1 is t. The acceleration of the object is in m/s(square), which basically means that the m is divided by s twice. For example:

A car was going at 45m/s. It accelerated constantly for 6s to 87m/s. Find its acceleration.
87=45+6a
a=7

Eq 2: t is the time interval from the time the object is at x0 to the time where it is reaches x. The logic behind it is that v0t is the distance the object would have travelled if it had not accelerated, and 1/2a(t)(square) is the extra distance it goes through acceleration. The reason why v0t is the distance the object would have travelled if it had not accelerated is pretty straightforward: it is the original velocity multiplied by the time it took. But why is 1/2a(t)(square) the extra distance the object goes through acceleration?

In the first equation we see that a times t is the difference between v and v0. In equation 4, we see that the average velocity is 1/2(v+v0). x-x0=v(average)t, thus x-x0=1/2(v+v0)t=1/2(v0+at+v0)t =v0t+a(t)(square)
Thus is equation 2.

Eq. 4: As it has been used in the previous equation, I don't think it needs a lot more explanation. The average velocity of an object, assuming it accelerates at a constant rate, is the average of its starting and ending velocity.

Eq 3: This is HARD!!! I will try to explain this, but it needs quite a bit of algebra and some things that are rather hard to explain in this manner. Thankfully, this equation is mostly only needed for certain proof and is not usually used in problems.

1st step: simultaneous equation
v=v0+at
x=x0+v0t+1/2at(square)
t=(v-v0)/a
Substituting into second equation:
x=x0+v0(v-v0)/a+a(v-v0)(square)/2a
Cancel a:
x=x0+v0(v-v0)/a+(v-v0)(square)/2
Multiplying everything by 2a:
2ax=2ax0+2v0(v-v0)+a(v-v0)(square)
2a(x-x0)=2v0v-2v0(square)+v(square)-vv0-vv0+v0(square)
2a(x-x0)=v(square)+v0(square)

Thus is equation 3. This is normally only used in situations where t is not mentioned and is unobtainable using any of the other equations (all of which contain t)

15/1/14

Here is one of the questions of the book that uses some (but certainly not all) of these equations. I will change it a bit or else it would be too complicated to explain without a diagram.

A car decelerates from 14m/s at 6.0 m/s^2. How far has it travelled during this time period?

Solution:
v/a=t
14/6=7/3=(about)2.333
(average)v=(v+v0)/2
(average)vt=x
(14+0)/2*2.333=(around)16
Ans: 16m

In 1D Kinematics, air resistance is ignored, thus all objects accelerate when falling at a constant rate of 9.8m/s^2.

Another problem:

A tower is 70m high. How far will a ball dropped from the top have travelled after (a) 1 second, (b) 2 seconds and (c) 3 seconds?

Solution:
(a)
In 1 second, the ball will have accelerated to 9.8 m/s since 9.8m/s^2 times 1s=9.8 m/s. The average velocity of the ball will be the average of the starting speed and the ending speed, namely 0m/s and 9.8m/s (note: this is only true for constant acceleration of the ball), which is (0 m/s+9.8m/s)/2 which is 4.9 m/s. You can then multiply this by the time to get 4.9m since 4.9 m/s times 1s=4.9m.
(b)
I shall not explain this one in words; if you don't know why I do certain steps refer to the example above.

9.8*2=19.6
(0+19.6)/2=9.8
9.8*2=19.6
Ans: 19.6m

(c)
Try this one on your own! The answer is 44.1m.

Note: the values are in the ratio 1:4:9. This is basically 1^2:2^2:3^2.
4.9/1=4.9
19.6/4=4.9
44.1/4=4.9

4.9=9.8/2
     =a/2

Thus we derive the equation 1/2a*t^2=x (recap: x is total distance travelled) which I have proved earlier (you can refer there for the proof). Try this equation for different gravities and the equation will still hold true. Actually, it is not just gravity-you can use this equation for any type of acceleration!

I think that will be it for 1D Kinematics. Now for 2D Kinematics:
_________________________________________________________________________________

2D Kinematics

2nd March 2014

2D Kinematics and 1D Kinematics are quite similiar except that now there is motion in 2 directions instead of 1. The main concept for 2D Kinematics is that you need to treat the motion as two separate motions in 2 different directions-not as one! For example, for a force exerted at a certain angle, you need to use trigonometry to calculate the force exerted in each direction, then calculate the resultant motion before finally using trigonometry again to convert both motions on the x and y axis into a movement at a certain angle in a certain direction.

For 2D Kinematics, you need some very basic understanding of sine, cosine, tangent, arcsine, arccosine and arctangent. Don't worry, most of the time you just need to know which function to use for what setting-let the calculator do the hard work for you!

One more thing-for physics, don't be afraid to use your calculator-for physics you need precision and accuracy, and calculators are there for a reason-to shorten the time you take to do the problem. Even if you can do the sum with some triple digit multiplication, just do it with your calculator. Our goal here is not to give you superb mental calculation, but instead it is to ensure that you understand the basic concepts and stuff-the actual calculation is not as important. Also for trigonomic functions you either use tables or a calculator, whereby the latter is much faster and more accurate, so try to use your calculator.

A basic introduction about a bit of the trigonomic function (note: what I will be stating will not be enough to equip you with sufficient trigonomic knowledge to solve the questions! If you want to do some reading up on your own)

First and foremost, sine, cosine and tangent only work for right-angled triangles!
However, when angles are involved, a vertical line can be drawn connecting the two lines that will form a right-angled triangle. From there sine, cosine and tangent can be used.

Triangles are made up of the hypotenuse, adjacent and opposite lines. Which line is which type all depends on the placement of the angle, theta. The theta sign looks like an italicised 0 that has a line in the middle.

Yup, that's the one.

Coming back to triangles.

The hypotenuse is the longest line in the triangle. The adjacent is the other line that is touching angle theta yet not the longest line in the triangle.

Trigonometry is based on one concept: when you have two lines, the ratio between them for a certain angle theta will always be constant. For example, when you have the opposite and hypotenuse, if you know the angle between them, and you know one of the measurements, you can use sine to find the relationship between the two measurements (a coefficient), then you can find the other measurement.

For example, I have a triangle. Theta=36 degrees. It is between the opposite and the hypotenuse. Thus here I can use sine.

If the hypotenuse is 25m:
sin(25)=opposite/25m
sin(25)=0.4226182617
0.4226182617=opposite/25m
0.4226182617*25m=opposite
Thus opposite=10.56545654.

Sine formula: sin(theta)=opposite/hypotenuse

The other two formulas work similiarly.

Cosine formula: cos(theta)=adjacent/hypotenuse

Tangent formula: tan(theta)=opposite/adjacent

To memorise the formulas for each trigonomic function, remember SOHCAHTOA. S, C and T are sine, cosine and tangent, while O, H and A are opposite, hypotenuse and adjacent.

There are three other trigonomic functions also involving these three sides but you will most likely not be using them for this section.




Now on to the physics...
_________________________________________________________________________________

27/4/14

In 2D Kinematics, you will be using a lot of VECTORS.

Vector~a quantity having direction as well as magnitude, especially as determining the position of one point in space relative to another

Vector diagrams are diagrams using arrows to specify the direction and distance travelled.

Here's a vector question.

John walked 27.8 degrees north from east for 65.7m. He then walked another 13.6 degrees south from east for 156.2m. How far is he from the starting point.

These questions are usually best visualised using a vector diagram but being unable to insert proper vector diagrams in here I shall try my best to explain the solution. If you do not understand just leave a comment in the comment box. (and your email?)

Remember what I said at the start of this chapter-the key is to see each motion as two separate motions in two separate directions. First you separate the two motions into 4 motions, 2 on each of the x and y planes. Find the resultant motion for both x and y before then combining them into a single motion with an angle.

(You will need trigonometry for this question)

First, 27.8 degrees north from east.
sin(27.8)*65.7=30.6416 (for physics questions I like to round to 4 decimal places, you can use 3)
cos(27.8)*65.7=58.1169

Since the vector arrow for this will be pointing more east than north, the motion will be largely east. Thus we can see that the first motion can be separated into two motions of 30.6416m north and 58.1169m east.

Next, 13.6 degrees south from east.
sin(13.6)*156.2=36.7292
cos(13.6)*156.2=151.8203

Since the vector arrow again will be pointing more east than south, the motion will be largely east. Thus the second motion can be separated into 36.7292m south and 151.8203m east.

Thus

30.6416-36.7292=-6.0876
58.1169+151.8203=209.9372

John travelled 6.0876m south and 209.9372m east.

To visualise combining them into one vector, we need a vector diagram.

--------->
              |
              |
              |
              |
              |
              |
              |
             V
Not drawn to scale (obviously)

At the meeting point between the two vectors, there is a 90 degrees angle. Here, we can use Pythagoras theorem. (You know what that is right)

For those who don't,



(Square root both sides to find c which will be the square root of the sum of a^2+b^2)

Thus using your calculator:

The square root of 6.0876^2+209.9372^2=210.0284.

To find the angle, you need to use tangent. Tangent theta is opposite/adjacent and in this case the downwards line is opposite angle theta marked by the brackets (sorry I don't have a better substitute) and the adjacent  is the horizontal line.

--------->
()            |
              |
              |
              |
              |
              |
              |
             V
tan(theta)=209.9372/6.0876
               =34.4860

To find what theta is, we use arc tangent (a.k.a tan^-1) to get theta=88.3390

Thus the resultant motion of John is 210.0284 metres, 88.339 degrees south of east.

_________________________________________________________________________________

A bit of clarification on how to know which value (sin or cos) is what value (horizontal or vertical)|:

Some times it can be blatantly obvious which direction corresponds to which value but at other times it can get rather confusing resulting in careless mistakes (which I make a lot of sad to say)

sin-opposite/hypotenuse
cos-adjacent/hypotenuse

--------->
              |
              |
              |
              |
              |
              |
              |
             V

Remember that the horizontal line is the adjacent and the vertical is the opposite (for this case only---always remember the definition of sin cos and tan using SOHCAHTOA in case you forget-it is a common careless mistake)

For a vector of m degrees, y direction above/below x direction with original vector distance k,

sin(m)*k=distance in x
cos(m)*k=distance in y

_________________________________________________________________________________

Introduction

Hello all who read this,

I am Chia Jia Nuo Daniel from Hwa Chong class 1i3. This is a Science blog that our class is supposed to make and update for the rest of the year. Its supposed to have what we learnt during class and some extra stuff. It will also be used to give me marks for my formative assessment for Science at the end of the year (Gulp!)

Please forgive me: I have never used a blog before, and though rather tech-savvy (I think), I still find blogging a rather foreign idea. Some of my classmates have fancier blogs; please don't judge mine by its cover!

Before I continue, let me clarify something: This blog is actually supposed to be a formal blog (I didn't know earlier). I will create a section (formal, labelled "for school") for the school to view and assess, and another section that I will just be doing for fun.

For my blog, I don't think I'll have time to watch interesting videos and post them, instead I'll talk about some of the (boring?) stuff from the Physics textbook I have been doing in the holidays. I find it rather interesting (at least my father's a physicist who can tutor me), I'm not sure about you. I might occasionally (or not so occasionally) add some other stuff, but for now I'm just going to post stuff from the uni physics textbook. (It really is quite interesting; ask me if you want to see it)

If you have any comments on how I should improve this blog (especially Mr Tan; can you tell me if I'm missing out important stuff)?

One more thing to note: as this is a step by step thing, some parts of the blog might not be complete at certain points in time (e.g. half finished post), so please bear with me. Especially those parts where it is kind of concluding your learning over the course of the year; that will often be incomplete. Also for the school viewing section most of it will just be the template for the time being, and I will only fill it up when I have the information.

Term 1 Week 2

Week 2. The serious stuff starts here. (Drum Roll) Or does it?

No, actually not. For now, it is still fun and games.

On Monday, we were supposed to have lessons in the lab but apparently our lab session was meant to be on Wednesday and Mr Tan was rather upset because he had half an hour of lab period less every week. However, we still continued lessons in the classroom.

We did an experiment with the "pink monster" (pink paper with ropes hanging out as arms and legs and tape in the inside; nothing too scary about it), where we had to tug at the different legs of the pink monster and see how the ropes were connected.

For our group of 5, one problem was that the ropes kept on getting taut, and we kept on forgetting to reset it, so we got a lot of false results. Another thing was that we always forgot to take down the orientation of the monster, so we couldn't take down which leg pulled which (actually all the legs pulled each other, but because of our previous mistakes, sometimes not all the strings were moving). In the end we had to use the direction of the monster's staples and the side where its slit faced to decide its orientation.

Later, Mr Tan revealed to us that this experiment was meant to explain to us some of the limitations of Science. Some things cannot be observed on the inside, we can only understand their properties when we try out different things on them; just like how we couldn't observe how the ropes were attached since they were inside the monster: we had to use other methods to draw observations. We also learnt that there are different approaches to problems, for example, in other classes, there were pupils who pressed the fingers on the paper to "feel" the rope. Afterwards, Mr Tan showed us the ppt for lab safety ("with a heavy Singlish accent" he emphasised).

On Tuesday (today) we learnt more about the scientific method (consisting of observation, question, hypothesis, methodology, result and conclusion) as well as graphing skills. We learnt how to start a graph on a number other than 0 (so as to expand our graph) as well as to draw a best fit line. The downside of drawing the best fit line is that the line can be rather hard to draw if readings are tightly clustered or very dispersed. An accurate best fit line can only be done in some cases with the aid of a computer. We also learnt about controlled, independent and dependent variable, and had a discussion about whether variables that seem inconsequential should be kept constant.

On Wednesday, we had our lab lesson. Mr Tan showed us the apparatus in the lab and told us the safety precautions we needed to follow in the lab. We then played (safely) around with a Bunsen burner and spark gun and learnt about a luminous and non-luminous flame. In the worksheet that we were given, one of the questions was: how do you heat alcohol safely without setting it on fire? After checking with my friends, I learnt that heating it in a water bath will ensure it does not catch fire as it is not in contact with an open flame. I did a bit of research about alcohol and learnt about the flash point and stuff; rather interesting stuff), but my answer was to use a thistle something, I can't remember what and place a substance that absorbs oxygen inside. Then pour the alcohol inside. The alcohol won't burn without oxygen even if you heat it with an open flame. I wonder whether my answer is correct?