How To Soar in PSLE - BTPS Way!!
Interact with complex questions / graphs / pictures to pick up valuable clues (don't highlight - just use your pen to underline words or scribble notes)
Start with Booklet A and do it meticulously with full focus - explore all 4 distractors before making final choice.
MANAGE your TIME - to score well, you need to try to finish ALL questions.
Specific answers = answers that are relevant to question.
When confused, choose any of the following strategies:
1. Ask, "What Science idea is being used in question?"
2. Pose other questions to clarify your thoughts
3. COMPARE to another set-up
4. COMPARE to a reverse situation
5. Connect to your knowledge in life (yes, you do have lots of prior / other knowledge)
6. Break down your answer in steps before crafting final answer.
Common problems with wrong answers:
*Answers are generic/vague and do not connect to that specific question
*Answers are not scientific and do not explain using Science ideas
*Answers do not make use of data provided when asked
*Answers did not make comparisons - use words like more/most etc..when asked
BTPS supports all P6 in achieving their PSLE GOALS!!
Roasting Chestnuts in China Town
Chestnuts are mixed with sandlike particles for roasting.
What is the purpose of using that?
(When in doubt about a question - always ask this: As compared to what?)
Therefore why should he use the particles instead of just placing the chestnuts straight on the fire?
How would changing the size of the particles affect the cooking?
Explain why.
Science Around Me (SAM)
SAM is a Science journal that allows pupils to express themselves in their favourite ways about Science.
SAM is another great opportunity for pupils to THINK and TALK Science in a medium that is customised to their learning styles.
SAM allows teachers to informally assess understanding of the child and clarify misconceptions in their learning.
When Ice Changes into Water by Goh Chee Yan - 5G
Do you wonder whether the mass of ice changes when it melts into water. Try this out:
1. Put a few ice cubes into a plastic bag
2. Tie the mouth of the bag tightly
3. Weigh the bag of ice cubes (if there is condensation outside the bag, wipe it dry before weighing)
4. Place the bag in the sun
5. When ice has melted, wipe the outside of the bag dry (refer to step 3)
6. Weigh the bag
You will discover that the mass of the bag remains the same!
There is no change in mass when ice melts!!
31 comments:
The purpose of cooking the chestnut with and sandlike particles is to cook the chestnut faster.The chestnut would cook slower if the sandlike particles are not inside,so people put sandlike particle inside to cook the chestnut faster.
People cook the chestnut on the spot and sell it to customers, that is why,they use the sandlike particle to cook the chestnut faster.
The sandlike particles are like sand and sand is a good conductor of heat,thus making the chestnut cooks faster!
Rachel---6 Faith
Well on a hot day , if you goto a beach ,and stand on the sand , bare footed , you realize that the sand is very hot ,same as the weather ,so ,i would say it can conduct heat fast .and people cook chesnut and send it to people on spot , so the vendors need the sand to cook , because it can conduct heat , and the chesnut and sand can be easilly seperated .
so i think that is why they use sand !
liping~6G
The sand particles are small and they covers more space around the chestnut and as sand is a good conductor of heat thus the cooking is faster and the customers would not have to wait longer
Kelvin Ruty 6 Grace
Cooking chestnut with sandlike particle is to cook the food faster as sand conduct heats faster.It conducts heat faster as there is less air spaces, so the smaller the sand particles the faster the chestnut is cooked.Without the sand particles the food will cook slower but the vendors have to cook it on the spot so they cannot afford to cook slowly.
But the smaller the particle the faster it cooks,so what is the difference between the big particle and the smaller particles?
The vendors would use the bigger particle to cook their chestnut as they do not want their chestnuts to be overcooked.Because the bigger particles have more air spaces in them which makes the cooking a little slower but prevents it from being over cooked. At least it is faster the cooking with no particle!
Ruyan 6grace
The frying of chestnut in small sand is to ensure larger surface are in contact with the chestnut in order for more heat to be conducted to the chestnut to cook it faster. -Stanley---6 Faith
It is to cook the chestnut faster. The sand particles has a smaller exposed area than the chestnuts. When there is smaller particles, there is smsaller air spaces therefore heat can pass through the sand faster. For the chestnuts, there is larger air spaces therefore the air in between them will keep on insulating the heat.
shanice yeo 6g
It is to cook the chestnut faster. The sand particles has a smaller exposed area than the chestnuts. When there is smaller particles, there is smsaller air spaces therefore heat can pass through the sand faster. For the chestnuts, there is larger air spaces therefore the air in between them will keep on insulating the heat.
shanice yeo 6g
the particles are usually good conductors of heat.by placing the chestnuts with the particles to roast,it will cook faster as we can use the heated particles to cover up the chestnuts and heat the chestnuts.by changing the size of the particles,we can roast the chestnuts more quickly or slow the cooking down.because if we increase the size of the particles,there will be a larger surface area for the heat to cover,so the particles will take a longer time to heat up,hence slow down the cooking.if we use smaller particles,there will be a smaller surface area for the heat to cover,so the particles will heat up faster and quicken the pace of the cooking...
-siqi[6grace]-
Chestnuts are quite big. Imagine putting only chestnuts in a bowl, how much surface of the chestnut will touch the surface of the bowl? Compare it with sand. Another example is when you go to the beach and walk on the sand, do you see your foot prints? YES!!! If you walk on a beach which is covered with chestnuts, do you see ur footprints? no... Why? That is because sand takes up more space! Same concept, when the uncle put the chestnuts in the bowl and roast it, less surface area of it touches the bowl and what is the rest fill with? AIR! Is air a good conductor of heat compared to sand? i doubt so... So the uncle uses sand to replace air instead, causing the whole interior surface of the bowl to be in contact with either the surface of the chestnut of the surface of the sand. When the bowl is heated up with the fire beneath it, it in turns heat up the sand particles and chestnuts, using the same principle, when the sand particles got heated up, it heats up its "neighbour"- the chestnuts! Thus it heats up faster than using air! Isnt that uncle smart?
#ZoEn#6G
The purpose of using sand like particals is to let the chestnut cook faster and not burnt.
As sandlike particals has air spaces,they are a good conductor of heat. Therefore, the sandlike particals can conduct the heat and then conduct away the heat.
lydia ng 6 grace
The purpose is actually to allow the chestnuts to be cooked faster because the sandlike particles are probably small and have lesser air spaces. It allows fire to travel faster, as compared to it travelling just through air.
I do not agree that the method mentioned above is actually faster but I think that the chestnuts might be burned just by placing it straight on fire. Using the above method might burn the chestnut slightly, but the particles are most probably "wrapped"around it and can reduce the chances of them (chestnuts) being burnt.
Using smaller particles will definitely be better than using bigger ones. The smaller particles have lesser air spaces compared to the bigger ones and will allow more heat from the fire to "enter" into the inside of the chestnut. The heat can be transferred from any direction and also partly because that chestnuts are not very big, it will take a shorter time to cook them.
Si Jia
6 Grace
The small sand particles is a better conductor of heat than air and it filled the space that are filled with air and make the chestnut heat up faster compare to filled it with a bigger particles and it would took a longer time to heat the chestnut
liweiwei
the sandlike particles will occupy the space in the bowl and will not let the heat lose to the surroundings.
Air is not a good conductor of heat and if we put the chestnuts just by itself in the bowl,the chestnut will cook slower than the one with the sandlike particles.as the cooker need to hurry, sometimes the chestnut is only half-cooked.the sandlike particles will take up space and there will be less air.
if we put rocks instead of sand,there will be a lot of spaces occupy by AIR.rocks have a larger surface area than sand.therefore,the chestnut bowl with rocks will cook slower than the on with sand.
the comment before this is syafiqah's..
Syafiqah 6Grace
Mixing the sandlike particles with the chestnut for roasting is to shorten the time needed to cook the chestnuts. If we use stonelike particles for roasting the chestnuts, the time needed to cook it will be longer compared to using sandlike particles. This is because when we are pack the particles together, there will be bigger air spaces then packing the sandlike particles. When we heat them up, the heat will travel through a smaller air space/ distance to reach the chestnuts, less time used.(sandlike particles) For the stonelike particles, the heat will also travel through, but it will have to go through a bigger air space/ distance to reach the chestnuts.
Chen Zung
6 Grace
Sand is a good conductor of heat which increases heat gain and heat loss. Also, sandlike particles are very small, from 0.825mm to 2mm(A mm is as small as this dash-. When the sandlike particles are being cramped together, the heat from the wok travel faster COMPARED TO no chestnuts or air(as air is a bad conductor of heat). So the chestnuts get cooked faster, the reason why the uncle want it to cook it faster because chestnuts taste nice when it is hot. After cooking the chestnuts, the uncle will put it in a pan with holes where the sand-like particles will fall out.
How would changing the size of the particles affect the cooking? Actually, Yes. The bigger the particles, more air spaces between them. Air is a bad conductor of heat so the heat from the wok travels slower, thus causing the chestnuts to be cooked slower COMPARED to smaller particles.(I am guessing if the costumer sees the BIG particle and it looks digusting, they will not buy it too).So big particles will allow the chestnuts to take a longer time and will not remain fresh.
MARCUS CHIOH 6G
It is to help to bring the temperature gradually to the desired heat then keep it constant so as not to dry or shrink the nuts. Also, sand is a good conductor of heat. (Imagine sand on a beach on a hot day).
However, by placing the chestnuts straight on the fire, it will take a longer time for them to be cooked as most of the heat emitted by the fire will be lost to the surroundings.
The bigger the size of the particles, the longer the time taken for the chestnuts to be roasted. As smaller particles are forthe heat to be retained, bigger particles would cause the haet to escape more easily.
~Nicholas King(6C)
The purpose of using sandlike particles is to cook the chestnut faster. When we place the sandlike particles together, we can see that the amount of air spaces between them is very little. And the points in which they touch each other is a lot, so they can conduct heat faster and cook the chestnuts faster.
If we compare it to not having any sandlike particles, the chestnuts will still be cooked, but taking a longer time. It will be longer as there will be more air spaces between the chestnuts. Air is a poor conductor of heat, so it will take a longer time. If we pour in the sandlike particles, they will 'fill up' the air spaces and take up the space. Thus having contact with the wok and the chestnuts.
The sandlike psrticles will have more contact with the wok which has been heated, thus heating up and then cooking the chestnuts.
Xinyi 6Grcae
I think the sand particles conduct some of the heat from the fire. The sand might be something like a temperature control. If the chestnuts were to go straight into the fire,BOOM! They would most likely be incinerated. If there was a slow fire, the chestnuts would take a long time to roast. The sand is a good conducter of heat so the chestnuts can be cooked over a big fire without getting burned to a crisp, thanks to the temperature controling sand. Timothy 6G
I think that the main reason is so that the chesnuts the Uncle sell will cook faster so that the customers would not have to wait. But why does it cook faster? Well, I think that it is because the sand particles are smaller than the chesnuts and can squeeze into the big airspaces between the chesnuts as they are circular. The heat from the flame below heats up the sand particles quickly because a bigger surface area is being heated at the same time. This heat is then passed on and on until a sand particle is next to the chesnut. Haha.. This is like a tour.. Anyways, if you imagine, the chesnut is humongous and the sand particle is smaller. If the sand particles were not there, the surface area that would be heated up by the flame is so small, but when the small sand particles are present, the sand particles touch the surface of the chesnut and so, the surface area of the chesnut that would be heated up would be bigger because the sand particles surround the chesnut, thus, the chesnut will heat up faster as the chesnut is being heated all around! The chesnuts and Uncle sure work hard... I hope that the people eating would appreciate the chesnuts... Haha...
What if the sand particles were bigger in size??
We are going to take a tour again! Imagine... A humongous chesnut is in front of you and between them are big sand particles. The surface area of the sand particle which touches the surface of the tool that the Uncle uses for frying the chesnuts is smaller than when smaller sand particles are used. The bigger the sand particle, the smaller the surface area is being heated thus, the chesnuts would take a longer time to be cooked.
Also, the chesnuts must at least cool down a bit right? So that the customers would eat without scalding their tongue, so, after cooking the chesnuts, Uncle must allow the chesnuts to cool first. Uncle is very clever, to cook fast so that the chesnuts would cool down more, letting the customers go away with BIG SMILES on their face while eating the YUMMY CHESNUTS! Haha...
oopsies.. the comment above is mine.. hahahahaha..
Yilin 6Grace
using sand like particles conduct more heat than just air beacause of more surface contact with the pan.
also solid is a better conductor of heat so to replace the air gaps between the chestnuts with a solid
but if you put the chestnuts. directly over a fire the chestnut is not only going to get cooked but also may catch fire.
calvin ho (6Grace)
The purpise of putting the chestnuts with the sandlike particles underneath it is to make the chestnuts cook slower. If the chestnuts it placed directly on the fire, the chestnuts might be burned. Another reason that might be is that the chestnuts at the bottom of the vat that is used to cook chestnuts might cook faster than the ones on top. when the chestnuts nearer to the top of the vat is cooked, the chestnuts at the bottom of the vat might be overcooked .
Another possibility that is the sandlike particles are a bad conducter of heat, thus the heat inside the vat is retained longer, so the chestnuts can be kept warm for a longer period of time.
-Benjamin Wong(37)
-6 Grace
When sandlike particles are placed in a bowl, you should see some spaces between them---Air spaces. Air is a bad conductor of heat, therefore,when the fire is turned on for cooking, the air in between the sand will slow down the 'process' of heat escaping to the surroundings. The sand is a good conductor of heat, thus it will cook the chestnuts faster. The air will keep the cooked chestnuts warm, instead of cooking it and cooling it. It might spoil the chestnuts. The bigger the soil particles, the the faster the heat conducted away to the surroundings. The bigger sand particles, the lesser air gaps there are.
Ben Wu, 6 Grace
I think that the uncle uses sandlike particles to cook together with the chestnuts as since sand is a good conductor of heat, it enables the chestnuts to be cooked faster.Moreover, customers who order chetnuts would want their chestnuts to be cooked fast enough right? Also the uncle would want to earn more money by using this type of clever methods. Smart, isn't he?
S.L.Keerthanna 6charity
i think the smaller the sand particles, the better. because when the particles are bigger, there will be more air spaces between the sand and the chestnut. therefore, the sand must have as much a contact as possible with the chestnut so that it can be roasted faster and stay warm for a longer time
6 Charity
Gu Yuling ( 6Charity):
I have actually thought of some other things than conductor of heat . (Firstly , I don't really think that sand is really a good conductor of heat & the hot sand on the beach should be due to the intense heat from the sun .Hence although it might not be a god conductor of heat , the large amt of heat supplied to it will still make it feel hot.)
From my point of view , the purpose of using sandlike particles is actually because of its tiny size which close up the gap between these substances and the chestnuts. With more surface of the particles in contact with the chestnuts , there is more friction . As friction produces heat , the heat produced is used to roast the chestnuts more effectively.
when placing the chestnuts sraight on fire , too much heat from the fire will travel to the chestnut and as a result the chestnut will not only get burnt , in a serious case , there might even be a fire.
By changing the size of the particles , there will be a bigger gap between the chestnut and particles , hence reducing friction , producing less heat to make the cooking more effective.
-I apologise for any mistakes in the above information as its only from my point of view.
I think the sand-like particles enable the chestnuts to cook longer so as to have a better flavour without being burnt. The sand-like particles like like sand, which is a poor conductor of heat. They allow heat to pass through slower than a good conductor of heat.
-Ong Yan Quan 6Faith
Sand is a good conductor of heat,therefore,the sandlike particles are to enable the food to be cooked faster.Since the vendor has to cook on the spot,he has to cook at a fast time to serve his customers,that is why they use these sandlike particles.
In addition,the sandlike particles has airspaces in between them.The size of the airspace would affect the time it takes to cook the chestnuts,with the larger the air spaces conducting more heat.Therefore,the smaller the particles, the shorter the time it takes to cook.
Chew Kai Wen(6C)
in western way of roasting chestnut in open fire, the cooks always recommend you to slice an X on the flat side of the chestnut to prevent it from exploding while being roasted. The Chinese sand pot seems cut this step short effectively, since we don't wanna cut that X 1000s time to sell a few bags of roasted chesnuts.
However, when you do eat, the X cut will bring that serving to the 5 star service. The Chinese roasted chestnut gives you no way but biting the nut out...
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