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

POST-IT notes - Science Magic

What enables Post It notes to stay up on any surface? 
Explain how that helps to keep the note up.

(When in doubt, ask other questions that can help you clarify how to answer the question) 

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.

Sea Bean Marvel

What is in a seed? How do you think it is dispersed?  

Although the Sea Bean is in a pod, it drops off one seed in one section at a time.  

How different is it from other legumes? Why has it developed this adaptation?

How Much Ice?

What is the effect of putting ice cubes in a glass  water? How does the number of ice cubes affect the time taken to melt in the liquid?

Sunny Sunflowers

What are the differences in the two flowers?

One seed or Many seeds? Explain how you came to your conclusion.

Creepy Creepers

What are the similarities and differences in the two plants below.

How do they overcome the problem of their weak stems?

Carnivorous Plants

The following plants are found in the wilderness in marshes and bogs.
Such plants feed on insects.

Compare these carnivorous plants to the ususal food producers.

What could be the cause of their physical and behavioural adaptation?

What are the consequences of their adaptation?

Cranberry Jam in a Jar

This jam was cooked with sugar before being placed in a jar.
What was the purpose of cooking the cranberries first?
How did the fungi grow inside the jar?

Cosy NEST

How does this nest differ from nests usually found on trees? What does it teach us about the birds who built it?

Life Without Simple Machines?

Imagine lifting this up?

Of all the simple machines you have learnt about, which one of them do you think Man cannot do without in everyday life?

Explain clearly why.

Simple Machines in a Construction Site

The above picture shows a construction site. The crane is used to lift heavy objects from a lower surface to a higher one using a pulley system.

If pulleys had not been invented, how can heavy materials used to construct buildings be moved to higher surfaces using other simple machines?

Tools and Simple Machines

The picture above shows 2 tools (ring spanner on left and spanner on right end).
What simple machines are used here? Explain using 'science language'.

Why is it necessary to produce various sizes of such a tool? Explain clearly by supporting your answer with valid reasons.

Simple Machines

The above toy used the concept of Simple Machines.

What simple machine is used here? Explain clearly how this toy can remain balanced.

Science in Hatchet

The questions below are based on your literature text Hatchet. Find the excerpts in your book before answering them.

It is important to follow these instructions if you wish to maximise your thinking:
1) Connect your answers to Science concepts - these are NOT questions about literature
2) Do not restate the facts as we can all read the text - we are interested in your thinking process!
3) Learn from your friends

Chapter 4, pg 33

"His clothes were wet and clammy and there was a faint chill. He pulled the remains of his windbreaker, pieces really around his shoulder and tried to hold what heat his body could find."

Q1) Explain clearly the chill that Brian felt.

Q2) Describe fully how Brian managed to 'hold what heat his body could find' despite the winndbreaker being in pieces.

Chapter 4, pg 32

"The darkness of the night was thick and for a moment, he began to panic again. To see, he thought. to see is everything."

Q3) Explain clearly why Brian couldn't see where he was?

Chapter 8, pg 75

"... he kicked out and threw the hatchet at the sound, a noise coming from his throat. But the hatchet missed, sailed into the wall where it hit the rocks with a shower of sparks..."

Q4) Explain clearly how the sparks were created?

Chapter 9, pg 84-85

"A cloud of sparks rained down, most of them missing the nest, but some ... hit the depression and of those six or seven found fuel and grew and cused the bark to take on a red glow."

Q5) In his attempt to make the fire, Brian selected four different items. How are these items similar?

Q6) Why was Brian able to light up the bark of the tree and not the twigs and grass he had used earlier?

Chapter 15, pg 130

"The birds were everywhere, five and six in a flock, and their camouflage was so perfect that it was possible for Brian to sit and rest...."

Q7) Describe two behavioural adaptations the foolbird displayed in order to escape from predators.

Q8) In what other way could one of these above behavioural adaptations help the foolbird?

Chapter 15, pg 133

"they were little more than sticks that flopped out of the bow, sometimes going sideways. Even when a bird was seven or eight feet away the arrow would turn without feathers to stabliise it..."

Q9) Explain clearly how feathers can help to stabilise the arrows?

Questions to Ponder

Is it true that went you want to heat something, you actually put in more mass .
Is it true that when you speed something up, it has more mass?
How can you tell Einstien's Equation was even right?
Why can't you travel beyond the speed of light?
How do you make sure your thinking is the right one?
Can you tell wheter people are telling the right facts?
How can you tell the Earth is round?
How can you tell green is green, you may take what I call brown as green and being taught its green, can you tell the differents at all?
How do you tell one another out, can you even remember their voice, Why?
A fish and a fungi, a protist and an animal, a plant and a amphibians, how do you group them all?

Try these questions out, ymay look simple but do try them, remember don't stop asking questions in science question it! Thats how science actually works!

Posted by Pek Yu-Xuan Sean

New Taxonomy?

Taxonomy is the art of classifying things. A few centuries back, a naturalist, Carl Linnaeus use a binomial system of classifying living things.

This system makes use of the animal characterisitics, for example:
Aves (Birds)
Pisces (Fishes)
Mammalia (Mammals)
Amphibia (Amphibians)
Phanerogamia (Plants with conspiciuous flowers)
This system make use of a binominal representation like for humans, Homo Sapiens , with Homo as the genus (Family) and Sapiens as the species.

While, Aristotle use thier movements of the animal to classify it - For example fish is classified as the swim for movement while birds are classified as Flying animals.

1)The Linnaeus system is now prefered over most system like the Aristotle one, what distinct advantage does it have over the latter?
2)The system has it flaws too! Can you name a few?

Posted by Pek Yu-Xuan Sean

Steam or Water Vapour

Before I go on the last post on the water rockets in Think and Talk Science1, if you are keen on finding out more about the question, please check the following before our last discussion:

1. How are steam and water vapour (in Science) similar and different
2. Are they visible?
3. How are they produced?

Last Post on BBQ Char Cool

Let me sumarise what "BBQ Char Cool" have said and let' s work from there.

'It is because of high chemical potential energy that enables it to burn for so long.'
Posted by Yu Ling

' The most common types of charcoal used are lump charcoal and briquettes. Briquettes are convenient, inexpensive source of fuel. It can burn more consistenly and longer then lump charcoal but not quite as hot. Charcoal can be burnt in power stations to turn generators to produce electricity. It can also be used to cook.

The porosity of activated charcoal accounts for its ability to readily absorb gases and liquids; charcoal is often used to filter water or absorb odors. Charcoal was also consumed in the past as dietary supplement for gastric problems in the form of charcoal biscuits.'
Posted by Xin Yi

'Disadvantages of using charcoal are that it is not a clean fuel. Charcoal transport generates more ash than LPG, Kerosene and Gelfuel.'
Posted by Pauline

'From what I researched, charcoal is a blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. The resulting soft, brittle, lightweight, black, porous material resembles coal and is 85% to 98% carbon with the remainder consisting of volatile chemicals and ash.'
Posted by Renise

Let' s stick to the instructions and give better awnswers!

Last Post on Porcupin

Debate on Porcupin - up to its chosen name was very animated! In particular, the observations made were objective and spot on. Answers on its physical and possible behavioural adaptations were relevant:

'When threatened, it will puff out its hairy thorns.' Posted by Nicholas King (6C)

We do know that puffing up makes organisms look larger and less vulnerable.

'The caterpillar has a fake eye on its back - the black dot - to mislead its prey that (the dot) is its eye ...' Posted by Kay Kiat

Question is "Why fake eyes?"

Finally, this comment by Marcus Chionh triggers other thoughts: 'MAYBE they do not have any spikes underside of it because they need to crawl, not curl up'

Many felt though that the absence of spikes underneath may help both actions of crawling and curling up.

We also know from our reading that caterpillars like to crawl underneath leaves as an extra precaution. Where do its usual predators come from? Mull over this as that was part of a PSLE question in 2008.

Last Post on Pollen - Welcome or not!

This question was fairly well debated with pupils making connections with what you have learnt, research and supported points made with examples from life around you.

The discussion on the pollination process was rich and I liked the comment by Sean Pek (6C) that flowers do know how to attract pollinators.

'I wish to explain how plants can 'lure' animals to pollinate them to the same plant, like being close to other plant so that the pollinator do not have to travel far to get more nectar, making the pollen land on the plant.'

I also think that Samuel Tay and Sean Pek below made some good points:

'Wind dispersed pollen must land on the same species of flowers to ... (fertilise the flower). Insect pollinated plants needs the help of insects to transfer the pollen grains from the anther to the stigma. For some species, if they do not land on the same type of plants, the pollen tube will not (grow). Some, however can cross breed.' Posted by Samuel Tay

'It is rare to crossbreed flowers of different genus ... if they have the chromosomes that are interchangeable, it may mix and the microgametophytes will mix with the ovum to form a seed. Finally, it seriously depends on its genus. If they are the same , most likely, there will be a baby (or egg).' Posted by Sean Pek

When we look around us, we do not see a large variety of cross-bred flowers for example. So maybe we should ask a different question: Do ovules accept all types of pollen?

Finally we thank all the curious pupils who gave us a good list of cross-bred animals - longest list went to Marcus Chionh (6G) - so my question is, "What do they have in common?'

I liked the heated argument by Ellia (6C) and comapny about cross-pollination and self-pollination. Maybe we can discuss during the next holidays!

Last Post for Mooncakes on the Moon

Some of you vaguely discussed the variety of mooncakes on the market - but did not delve deep enough into the facts.

There are two main types sold in Singapore, notably the brown skin classic with yolks or not and the ones covered with a soft skin called 'snowskin'.

The boxes both came from upmarket hotels and the styrofoam one came with 'snowskin' mooncakes. The elaborately decorated one is made of medium-thin cardboard and came with brown skin mooncakes and a sachet of dessicant.

Last question is therefore what is the purpose of the two types of insulators. There is a reason for the styrofoam which if compared to cardboard is a far more effective insulator. Part of the answer might lie in this statement made by Rachel Neo (6F) - 'Some of the boxes are airtight,while others are not'.

It will be good to think of the mooncakes and their 'skin' mentioned above when thinking of an explanation.

BBQ Char Cool 2

It is important to differentiate coal and charcoal - fossil fuel v/s just trees that have been treated. Please also read the comments from Pauline who clearly states some of the benefits of charcoal. Also Xin Yi and Renise gave some relevant information on charcoal.

Maybe some of you can elaborate and make the differentiation clearer to the confused ones.

The comment by Yu Ling on the chemical potential energy of charcoal is well connected to the current P6 topic.

Also I agree that it's so much preferable to write in your own words to show what you understand. Short, concise comments do a better job than long explanations.

Pollen - welcome or not?

A jaglion(offspring between a male jaguar and a female lion.)

Mooncakes on the Moon 2

That was a great debate on mooncakes - errr but there is severe digression. It is important to know when to control our thoughts and get back to the focus.

Great input:

1) Insulators
2) Warm or cold moncakes
3) Material

All else is detracting from the main focus which is Science here.

No one has adressed the similarity stated by many of you: Both are insulators. Then how does one insulator differentiate form the other? Is the purpose of the insulator in both cases different?

Many discussed material used - does that have an importance besides aesthetics - please move away from that point because you are missing important Science facts here!

But most importantly, did anyone ask around or think about the main types of mooncakes available in Singapore? Please note the word "MAIN". Do they affect the types of boxes used? The long discussion of eating cold or warm mooncakes should have been such a good clue.

Finally, to say that styrofoam is probably not from an expensive restaurant is a subjective comment because it is impossible to tell just by looking at a picture. I will divulge more later.

I enjoy the chatter as only through free Talk can we clarify our own thoughts. We must be willing to change our thoughts after "listening" to others when they make sense. It is not a case of "Hear me. I'm right!' Comments that make sense have been researched and are well suported by facts and examples.

Let's focus on making our chatter productive and fun at the same time.

UFO - Unravel For Own understanding

Are there really UFO's or are they just a Fake scam?

Pollen - Welcome or Not?

How does pollen know where to land?
Are all types of pollen accepted guests on all types of stigmas?

How about animals? What happens when a male of one species mates with the female of another species? Do we have a baby?

BBQ Char Cool!!

Who doesn't love a juicy chicken wing grilled to perfection above charcoal?
What is charcoal and why is it possible for it to burn for such a long time?
What is/are the difference/s between charcoal and its original state?
I hear charcoal has many other benefits.
Tell me about some of them.
But of course there are disadvantages to using charcoal.
Suggest some possible ways of harnessing the goodness of charcoal while minimising harmful effects.

Comment on THINK SCIENCE TALK SCIENCE 1

The pupils were at the Mindfest at the Science Centre.
What do you think caused the bottles to shoot up?
What do you think is coming out of the bottle?
How do you think it was formed?

Comment on THINK SCIENCE TALK SCIENCE 2

Observe Porcupin.
Porcupin is a caterpillar found in the school carpark.
What physical adaptations help Porcupin in evading predators?
Besides physical adaptations, how else do caterpillars behave in order to survive?

MOONCAKES on the MOON?

In Singapore, different types of mooncakes are sold in different types of containers.
In what ways are the containers similar and in what ways are they different? What is the reason for choosing different types of containers?