There is More to Cycling than just a Bicycle!

Picture From 3M

Explain clearly how clothes/gear with reflective material can help a person cycling at night?

Whenever you are unsure about how to answer a question, you can compare the situation to a reverse situation: here - wearing clothes with no reflective material.

HOLIDAY Fun!

During his holiday at Sentosa, Jason woke up at 6 a.m, jumped into the swimming pool and yelped,
"Wow! It's sooooo cold!"
He quickly got out and went back to the hotel room and jumped into his bed with his wet swimming trunks.
"OOH, this is so warm and toasty!"

What made Jason feel cold in the pool? (Remember, always connect to Science concepts).
What made Jason feel warm in bed?
Explain clearly why.(You can try to connect to a similar experience you had!)

Stones and this time - FOOD!

Nomadic tribes (people who move from one place to another) use stones to cook their food. Here bread is being cooked on stones that are placed on fire.

Explain how you think the stone helps the bread to cook.

How is the process different from using a metal wok for example?

Would the cooking time be different if several smaller stones were used instead of one large piece?

Stones and Health? Not Stone Age!

In Finland, people go to saunas (hot houses) as they believe it's a healthy way to relax. Stones are heated up inside a well ventilated (air can move in and out) room.

When the stones are ready after 2-3 hours reaching temperatures higher than 100C, water is poured on the stones.

Imagine what happens as soon as water touches the stones!

Explain what you think happens. (Remember steam can't be seen.)

How does this process help the occupants feel warm?

Why do people pour water on the stones instead of just warming the room up with a heater?

Shadow Puppets

Shadow Puppets
How do you think the shadows are formed?
What could cause the shadows to become blurred or coloured? 
Explain what tricks can be used to achieve bigger and smaller shadows.

Packing - think again!

Why are people often being advised to pack light when they travel?

What do you know about Science that helps in packing light?

Explain how this is achieved.

Do you think that in Science, the packaged clothes are truly lighter?

Share your thoughts.

Going Places?

A wollen sweater

A windbreaker

Alice is planning to go Country X at the end of the year. The temperature there ranges from about 13 degree Celsius to 22 degree Celsius.

1. What are the similarities between the choices above?
2. What are the differences between the two choices above?
3. Which of the above, a wollen sweater or a windbreaker, should she choose to bring along for her trip?
4. Give reason(s) for your choice.

Flasks and their Secrets!

Have you ever used or seen someone use a flask like the one on the picture?

They are called thermos flasks and people use them to contain either hot or cold beverages.

List the materials used and explain how they help in making this item useful?

In what ways do such flasks keep hot beverages warm and cold beverages cool?

Chestnuts

Extra Q1: Is sand really a good conductor of heat?
Please note that it is very important when discussing conductivity to analyse in comparison to what else.

Compare Sand to just Air:
Is Air a good conductor of heat compared to Sand? (Zoen asked)
Air is not a good conductor of heat - Syafiqah

Compare Sand to Metal:
Sand on the beach absorb the heat from the Sun - but if you dig deep inside beyond the upper layers of sand, you will find that the bottom layers remain cooler than the top layer.
Imagine (excellent strategy advocated by Yi Lin) layers of metal under the sun. What do you expect to happen?

Extra Q2: Is cooking time shorter or longer?Compare Cooking with Sand and Cooking without Sand - the answer will be clearer to You
The sand might be like a temperature control. If the chestnuts went straight into the wok on the fire, they moght get 'incinerated'. If there was a slow fire, the chestnuts might take a long time to roast. Chetsnuts can be cooked over a big fire without getting burnt thanks to the 'temperature control' - Timothy

Sand helps to bring the temperature gradually to the desired heat then keep heat constant so as not to dry up / overcook the nuts - Nicholas king

Compare Top layer to Bottom layer of chestnuts
Another reason might be that the chestnuts at the bottom of the vat might cook faster than the ones on top and end up overcooked - Benjamin

What could have happened then:

1. Sand particles close the gaps between the chestnuts (Yu Ling)
2. Sand will not let the heat be lost to the surrounding (Syafiqah)
3. Smaller particles of Sand helped to retain heat whereas larger particles might cause heat to escape - Nicholas King
4. When sand particles get heated up, they heat up the neighbours' - conduct/transfer heat to the chestnuts - Zoen
5. So it seems that distributing heat evenly to the chestnuts is important just as keeping them warm while cooking them slowly.

Cranberries

Here are some of the answers:

(Relate to process of cooking and preservation connected to Science )
The purpose of cooking the jam is to kill bacteria in the cranberries - Si Jia
The canned food we have are also heated before being put into cans to be sent off to supermarkets - Ong Yan Quan
Foods are also preserved through other methods such as: Salting (eggs), pickling (vegetables) - Nicholas King

(Relate to Fungi and environment that are conducive to their growth)
The main reason for the fungi to grow inside is due to its exposure to either oxygen or warmth. Si Jia
The jam is also moist - Rae Ann
Fungi are Decomposers and they need warmth, air and moisture - Abraham


(Connect to other knowledge - finding plausible reasons using Science concepts)
My grandmother shared with me that one must also heat up the empty glass jar as there might be organisms living inside the jar itself - Yun Na
The 'machines' that were used to make the jam were not clean and could have contained spores - Benjamin
After the cap is open, air can go in and maybe fungi and bacteria went in - LiPing