Homework help?

[SeagullTim]

I've got some Physics homework and I'm really confused :S.

Anyone good with Radiation and Conduction questions?

The ones i'm stuck on -

Conduction

Why can sheets of newspaper be used to keep ice-cream cold or chips hot?

Radiation

Why does a shiny teapot stay hotter than a dull brown one?

Why are fire fighting suits made of shiny material?

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?

Why is the back of a refridgerator painted black?

Help is greatly appreciated, thanks.

 

[Frutos]

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?.

I don't even understand that question, so I have no hope of getting the answer right.

If it was French or German homework, I'd be quite good at that I think, but Science was never my strong suit.

 

[Muhammed - I’m hard - Bruce Lee]

Why is the back of a refridgerator painted black?

ah see, i know this one


its to deflect ambient temperature away from the foamed in sensors, so they pick up on the temperature in the cabinet rather than the temperature in the room


i think all the others are trick questions
hope this helps

 

[Beach Hut]

Easy - because they are

You'll understand this later in life when you ask your IT department a question.

 

[Zesh Rehman]

if i were you i would drop physics, i did

 

[Gully]

The sheets of newspaper are poor conductors of heat, therefore they don't let the heat of the fish and chips out, thereby cooling them or at the other extreme the warmth in to warm up the ice cream.

Not sure about the cloud question, are you sure that it was written down properly. It is more likely to be "cold" on a cloudless night than a cloudy one because the heat of the ground/buildings etc is allowed to radiate away. If it is cloudy some of the heat is trapped.

That is the first time I have had to use my O/Level Physics (Grade B) since passing the exam at Steyning GS in 1982.

 

[withdeanwombat]

"The back of a fridge is painted black so that you can tell it from the door."

EINSTEIN

 

[Monkey Man]

That homework is really hard compared to my kid's. He has to learn to identify some of the words in Humpty Dumpty and colour in a picture.

But then he is four.

 

[Muhammed - I’m hard - Bruce Lee]

That homework is really hard compared to my kid's. He has to learn to identify some of the words in Humpty Dumpty and colour in a picture.

But then he is four.

 

[pasty]

That is the first time I have had to use my O/Level Physics (Grade B) since passing the exam at Steyning GS in 1982.

Good job you're here then, I failed physics O-level in 1982

 

[Gully]

I managed to get a U in chemistry, not a surprise really as we just arsed around having water fights and trying to burn things, still not sure how I managed to pass Physics.

 

[El Presidente]

Radiation

Why does a shiny teapot stay hotter than a dull brown one? Because it reflects heat back into the inside of the teapot

Why are fire fighting suits made of shiny material? As above, they reflect heat back to the source

Why is it more likely to be cold on a clear night than on a cloudy night?

Clouds act as an insulator

Why is the back of a refridgerator painted black?

To ensure that racial quota targets under New Labour are met (well that's the answer according to 'The BNP Book for Real Boys' anyway)

 

[Robbie G]

I've got some Physics homework and I'm really confused :S.

Anyone good with Radiation and Conduction questions?

The ones i'm stuck on -

Conduction

Why can sheets of newspaper be used to keep ice-cream cold or chips hot?

Radiation

Why does a shiny teapot stay hotter than a dull brown one?

Why are fire fighting suits made of shiny material?

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?

Why is the back of a refridgerator painted black?

Help is greatly appreciated, thanks.

I'll have a guess at what i think the answers may be...

Newspaper used because it doesn't conduct heat as much therefore not a lot of heat is lot (in the case of the chips, vice-versa for ice-cream)

Shiny suits for firefighters to "reflect" the heat from fires, therefore causing them not to overheat or burn?

Cloud question must be why is it colder on clearer nights. Same logic for using tea cosy for tea pot, clouds keep the heat of the sun in.

Refrigerator question i haven't a clue, but been answered above

I'm not sure about the shiny tea-pot question. If i were follow the logic of my answer to the fireman question, i would say it's so the heat is "reflected" inside the tea pot, as a dull brown surface would absorb the heat meaning the tea would become cold quicker?

Not sure if any of this correct, but i only did Science GCSE

 

[Theatre of Trees]

Good job you're here then, I failed physics O-level in 1982

I'm the proud owner of a grade U for CSE Physics also taken in 1982.

 

[The Clown of Pevensey Bay]

I've got some Physics homework and I'm really confused :S.

Anyone good with Radiation and Conduction questions?

The ones i'm stuck on -

Conduction

Why can sheets of newspaper be used to keep ice-cream cold or chips hot?

Radiation

Why does a shiny teapot stay hotter than a dull brown one?

Why are fire fighting suits made of shiny material?

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?

Why is the back of a refridgerator painted black?

Help is greatly appreciated, thanks.

Have you tried turning it off and turning it on again?

 

[tedebear]

I've got some Physics homework and I'm really confused :S.

Anyone good with Radiation and Conduction questions?

The ones i'm stuck on -

Conduction

Why can sheets of newspaper be used to keep ice-cream cold or chips hot?

Radiation

Why does a shiny teapot stay hotter than a dull brown one?

Why are fire fighting suits made of shiny material?

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?

Why is the back of a refridgerator painted black?

Help is greatly appreciated, thanks.

The answers are in the topics...

Conduction - New paper has a low thermal conductivity - ie materials with low TC will transfer small amounts of heat over time, like insulation in your house....If the newspaper had a high thermal conductivity all the heat would be transferred out of the fish and chips at a high rate and your food would be colder quicker!

Here:

Conduction

Radiation - Radiation is the emission of energy in waves or particles.

Refridgeration is the removal of the heat in the air of the fridge. air removed from the fridge turned to liquid by refridgerant gas is run through the fins at the back of your fridge (the gas actually heats the liquid) and as they are fins (large surface area) and black (high conducting colour) the heat radiates out and leaves the system.

Got to run now but thats a start...

 

[tedebear]

Heres your cloud answer too...(I'm assuming your question has a typo and you meant why is it cold on cloudless nights)...

http://earthobservatory.nasa.gov/Library/Clouds/

 

[Ccider]

I've got some Physics homework and I'm really confused :S.

Anyone good with Radiation and Conduction questions?

The ones i'm stuck on -

Conduction

Why can sheets of newspaper be used to keep ice-cream cold or chips hot?

Radiation

Why does a shiny teapot stay hotter than a dull brown one?

Why are fire fighting suits made of shiny material?

Why is it more likely to be cloudy on a clear night than on a cloudy night? WTF?

Why is the back of a refridgerator painted black?

Help is greatly appreciated, thanks.

The newspaper one has nowt to do with the conductivity of paper but AIR. If you wrap several sheets of paper round your chips there will be air trapped between the layers and air is a real crap conductor of heat.

The others are just white/shiny things reflect/don't radiate as good as black/matt things that radiate well/absorb well.

The cloudy night is a typo I guess - it should be "why is it more likely to be cold on a clear night than a cloudy one" and the answer is that the clouds (being white) reflect the heat radiated by the ground back down again so keeping it all in as they say.

Hope this helps.... keep up with the Physics - your country will need you!