Box with a jumper/blanket on top, cooling or heating?

In summary, the conversation discusses the use of a jumper or sweatshirt as a means of cooling without a power supply. It is suggested that the jumper acts as an insulator, preventing heat transfer and allowing for the evaporation of water on a wet blanket to cool the surrounding area. There is confusion about how the jumper works and whether warm water would have the same effect.
  • #1
aspodkfpo
148
5
Homework Statement
Kate has a bucket of ice cream and wants to take it on a long car trip into the desert, so she wraps it in a jumper. Is this a good idea? Choose the best answer.
Relevant Equations
nope
Apparently the answer is to have the jumper over the bucket. Am I wrong in thinking that the jumper transfers heat to the ice cream, why does it not do so?

A similar question elsewhere was "Colin claims to have built a refrigerator alternative which works without any power supply. It is a box with a wet blanket over it; the blanket is kept wet as a tap is allowed to drip onto its corner. How does it work?" where apparently it takes energy to evaporate the water on the blanket and thus it keeps is cool. Similarly I thought that warm water would cause the blanket to transfer heat?
 
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  • #3
Chestermiller said:
what's a jumper?

a sweatshirt/jacket

can someone please answer? Bump
 
  • #4
aspodkfpo said:
a sweatshirt/jacket

can someone please answer? Bump
A jumper insulates, i.e. it inhibits transfer of heat in either direction. The heat already present in the jumper soon becomes irrelevant.
 
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1. How does a box with a jumper/blanket on top provide cooling or heating?

The box with a jumper/blanket on top works by insulating the contents inside. The jumper/blanket traps air and creates a barrier between the contents and the outside environment. This helps to slow down the transfer of heat, keeping the contents cooler or warmer for longer periods of time.

2. Can a box with a jumper/blanket on top be used for both cooling and heating?

Yes, a box with a jumper/blanket on top can be used for both cooling and heating. The insulation provided by the jumper/blanket works in both directions, preventing heat from escaping during cooling and trapping heat during heating.

3. How long can a box with a jumper/blanket on top keep its contents cool or warm?

The duration for which a box with a jumper/blanket on top can keep its contents cool or warm depends on various factors such as the insulation properties of the jumper/blanket, the outside temperature, and the contents inside the box. In general, a well-insulated box with a good quality jumper/blanket can keep its contents cool or warm for several hours.

4. Is a box with a jumper/blanket on top more effective than a regular cooler or heater?

It depends on the specific situation. A box with a jumper/blanket on top may be more effective in situations where a cooler or heater is not readily available. However, a regular cooler or heater may be more efficient in maintaining a specific temperature for longer periods of time.

5. Can a box with a jumper/blanket on top be used for transporting temperature-sensitive items?

Yes, a box with a jumper/blanket on top can be used for transporting temperature-sensitive items. The insulation provided by the jumper/blanket helps to maintain a consistent temperature, making it suitable for transporting items that require specific temperature conditions.

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