Question

Consider 2 different covered cups containing the same amount of hot water, initially at the same temperature.
Which of the cups will cool down at a faster rate?

Cup A (Covered Styrofoam Cup) has 100 g of water, and it is 55 ℃
Cup B (Covered Shiny Metal Cup) has 100 g of water, and it is 55 ℃

1. Not enough information is given.
2. Cup A will cool faster than cup B.
3. Both cups will cool at the same rate.
4. Cup B will cool faster than cup A.

Answer 1

i think option 2 is correct as,
if we cover a cup with a shiny metal cup, the shiny surface will reflect the heat that is gonna be lost

Answer 2

That's what I thought too, but I wasn't sure.

Answer 3

i think what you(and me) thought was right!

Answer 4

So, Cup A (Covered Styrofoam Cup) will cool faster than cup B (Covered Shiny Metal Cup), right?

Answer 5

No, it is not option 2!

Answer 6

Wouldn't both cups cool at the same rate, option 3.

Answer 7

?

Answer 8

Hey, are you there?

Answer 9

Wouldn't both cups cool at the same rate, which is option 3?

Answer 10

Help!

Answer 11

Someone there?

Answer 12

what is difference between metal and styrofoam?

Answer 13

metals have the greater ability to conduct heat than styrofoam,so metals would maintain the heat less then styrofoam. But as rajat97 said metal can reflect the heat while styrofoam can't. So metal is gonna lost heat due to heat conduct ability relative to styrofoam but is gonna keep heat longer due to reflection of heat waves. You cannot tell now whith information given which material would cool faster. I think it's A

Answer 14

I also feel not enough information is given. The metal cover will conduct the heat more than the styofoam but as Fifciol said, it would also reflect more heat than the foam.

Answer 15

Here's another question:
The same two cups, under the same conditions, but this time Cup A is covered with shiny metal cup, and cup B covered with dull black cup, which of the cups will cool down at a faster rate?

Answer 16

same mass, same temperature.

Answer 17

Here's another question:
The same two cups, under the same conditions (same mass, same temperature), but this time Cup A is covered with shiny metal cup, and cup B covered with dull black cup, which of the cups will cool down at a faster rate?

Answer 18

It will probably be the dull black cup. If you look on the inside of a thermo flask you will see a reflective lining on the inside. This is to keep the heat in. A black dull cover will absorb heat radiation, have a look at black body radiation on wiki

Answer 19

So, Cup B (covered will dull black cup) with cool down faster than Cup A (Shiny Metal Cup)?

Answer 20

I think that's what the question is getting at, maybe someone else will see it a different way.

Answer 21

Yeah, you were right!

Answer 22

I'm just still not sure about the first question I asked.

Answer 23

I also feel not enough information is given, but I'm scared to enter the answer; I get negative points if the answer is wrong!

Answer 24

Excellent! I'm not sure myself about the first question, it's either conduction of the metal emitting more heat radiation or the metal reflecting more heat thus cool down at a faster rate. I couldn't give a reliable answer, maybe someone else might have a little more insight

Answer 25

Thank you so much - I really appreciate it! I hope someone else can help with that question.

Answer 26

good absorbers are good reflectors
i think this concept is used in both the questions

Answer 27

oh i' sorry good absorbers are good emmitors

Answer 28

So, what would be the answer?

Answer 29

for question 1, i'm not sure as i think that optoion 2 is correct
for the second question , i have a logic
look dull black things are good absorbers and good absorbers are good emmitors so the black cup will emmit its heat faster and cool down faster
hope this helps you
'll get back and help you:)

Answer 30

The cups are not covered by styrofoam or metal, but as I understand it are MADE of styrofoam or metal.

The metal cup will cool much faster as metal is a much better heat conductor than styrofoam.

Answer 31

So, Cup B (Covered Shiny Metal Cup) will cool faster than cup A (Covered Styrofoam Cup), right?

Answer 32

Yeah, you were right! Thank you so much for all the help! :-)