Would it be more efficient to warm your bed on a cold night with a hot water bottle that contains 1kg of . . .

Question

water at 50 degrees C or with a 1kg gold bar at 50 degress C? Why?

Answer 1

gold because it holds and conducts heat quicker and longer.

Answer 2

Just answering this off the top of my head, I think water has greater heat capacity than gold. The molecules in a solid gold bar can't move around as much as the molecules in liquid water, and heat is basically the kinetic energy of molecular motion. If the gold were liquid, it would probably have much greater heat capacity, but then your bed would catch fire and the gold would probably melt down through the mattress and the floor, setting it on fire. So I would definitely go with the water.

Answer 3

If the water stays in the bottle, the gold bar is more effecient.There is less energy loss to the surroundings in the conduction of heat from the goldbar to the bed than the conduction of heat from the water to the bottle and then from the bottle to the bed.

But if the water is sprayed over the bed, of course its more effecient. Not only does the surface area for conduction of heat increases multiple times, water has a lower heat capacity than gold too.

erratum:
after reading some answers: id_ego_superid is correct. Water has a higher heat capacity than gold of the same mass and not as i stated above(sorry i mixed it up). Heat capacity refers to the amount of energy required to have an increase in the temperature of a unit mass of a substance of 1 degree Celsius in 1 second. Your gold heats up relatively faster.

Answer 4

The specific heat of water is about 4.18 J/g K at 25 degrees C, whereas gold is about 0.129 at the same temperature. The water will give you more than 30 times the heat than the same mass of gold.

Answer 5

With water, sprayed on the bed because of higher heat capacity (as others pointed out).
So, immediately after the heat exchange between the water and the bed, you of course feel warm on the bed. However, as time passes, water on the bed starts to cool off and when it reaches just below your body temperature, you'll start feeling cold again on the bed as the water starts to take heat off your body (as well as the bed, probably to a lesser extent) and finally when it is colder than the room temperature, it'll be worse (colder) than when you started off...

Answer 6

If I could freaking warm my bed with 1kg gold bars I think I could find somebody else to warm it properly, if you get my drift.

Answer 7

water. heat capacitance. the gold will be cool faster. Makes a good heat sink. Like copper. OOOh I wonder if I can get a zalmann heat sink made of a pound of gold instead of copper. WEEEE yay physics!

Answer 8

Hot water, because water is a better conductor of energy, or heat, than is gold.

Answer 9

whilst the temperature dropped under -20 ranges F (approximately -30 C) right here in Chicago this previous wintry climate, i chanced on that purely layering up helped. My mattress become set up with right here: mattress pad, flannel sheet set, a microfleece blanket, cotton comforter from objective, and 2 small fleece throw blankets. as nicely to this i'd placed on fleece pajama pants, a protracted-sleeve knit shirt, a pair of thick socks...and that i oftentimes ended up scooting my head/pillow under all the mattress layers till my physique warmed up.

Answer 10

gold bar because it conducts heat faster. and water is slower.