# Physics

posted by .

A friend asks for money to market a new product he invented. He claims to have invented a "cold plate" that works like a hot plate and will cool down foods and liquids that are placed on it. Should you invest??

Should I be thinking about the second law of thermodynamics here?

• Physics -

When you put electricity into a hot plate the electrical energy is converted directly to heat energy by the resistance of the wire. That makes the plate hot and the heat transfers to the food by conduction and radiation
Now if we could come up with a way to put electricity into the plate and make it cold, the heat in the food would be transferred to the cold plate by radiation and conduction thereby achieving the desired result.
However there is a problem. We do not have a way for the electricity to carry heat away from the plate. It puts power in. It does not take it out. It would have to run a machine that transfers heat from the cold plate to some warmer sink. That is called a refrigerator. In fact the surface of the freezing compartment in your refrigerator would work just fine for this purpose with the cold pipes full of expanded gas running through it. The heat generated by the electricity running the compressor is dumped to the air outside the refrigerator by coils out in the air behind the unit.
This would work fine, but is not anything like the simple concept of the hot plate because we need that entire machine between the plug and the wall to pull heat out of a cold thing and dump it to a hot place.

## Similar Questions

1. ### need some ideas- inventions

For my Intro. to Business class, I am supposed to come up with a new product or an old product with a new twist. It has to be something that you know for a fact can be made in this time period. Everything I think of, somebody has already …
2. ### Geological Events

Hot spot volcanoes appear as volcanic chains in the middle of an oceanic plate because as the plate moves away from the hot spot, the volcano becomes less active, then the hot spot forms a new volcano. Is my answer correct.
3. ### Physics

A square plate of copper with 53.0 cm sides has no net charge and is placed in a region of uniform electric field of 77.0 kN/C directed perpendicularly to the plate. Find the charge density of each face of the plate.
4. ### Physics

A crown glass plate 2.5 cm thick is placed over a newspaper. How far beneath the top surface of the plate would the print appear to be if you were looking almost vertically downward through the plate?
5. ### Physics #48

An electron is released from rest at the negative plate of a parallel plate capacitor. The charge per unit area on each plate is σ = 1.67 10-7 C/m2, and the plate separation is 1.35 10-2 m. How fast is the electron moving just …
6. ### Physics

An electron is released from rest at the negative plate of a parallel plate capacitor. The charge per unit area on each plate is σ = 1.67 10-7 C/m2, and the plate separation is 1.35 10-2 m. How fast is the electron moving just …
7. ### Aplied maths

1. A steel plate initially at 21.2°C is placed in a furnace at 785°C for 58.0 minutes. While in the furnace the temperature of the plate increases at a rate of 4.18% per minute. After 58.0 minutes, the plate is removed from the furnace …
8. ### Art

in modern printing technology what important type of plate is created a nickel salt solution?
9. ### Physics

When boiling​ water, a hot plate takes an average of 9 minutes and 47 seconds to boil 100 milliliters of water. Assume the temperature in the lab is 75 degrees Fahrenheit. The hot plate is rated to provide 195 watts. How efficient …
10. ### world history A

Which best describes how the Agricultural Revolution has affected modern society?

More Similar Questions