Yup... Both...tried it with my Class after reading James & the Giant Peach...even fresh vs. salt water...floated
Yes
Cold water.
Yes, as hot water is less dense than cold water so it will float on top of cold water. Over time the temperatures will equalise due to natural conduction and convection.
In hot water the molecules vibrate faster than cold, resulting in the same number of molecules taking up a larger space. This means that hot water is less dense than cold water, and thus floats above the cold water.
The density of cold water is greater than hot water so there will be more substances that will float in it.
The difference in water density (hot-cold) is very small, compared to the difference in density between water of any temperature, and your body. That is, even hot water is more dense that we are, so we still float.
Flour to cold water will just float on top, hot water to flour will cook the flour.
Cold will sink to the bottom. Hot water will rise to the top.
Yes, fresh eggs typically sink in water, but as they age, the air cell inside the egg grows larger, causing the egg to float. This is because old and stale eggs have more air inside their shells. Temperature doesn't have a direct impact on whether an egg will float or sink, but colder water can slow down the release of air from the egg, so it may take longer for a fresh egg to float in cold water compared to room temperature water.
a steel ball bearing will drop faster in warm water then cold water, a beach ball will float better in cold water because cold water is more dense.
It is easier to float in cold water because cold water is denser than warm water, providing increased buoyancy to support the body. Additionally, cold water can cause vasoconstriction, reducing blood flow to the extremities and helping to conserve heat, which can also contribute to buoyancy.
It would depend on the item of course... it would take an awful lot of salt to make a bar of steel float. Likewise, a sealed empty bottle might float on either cold or hot water. However, water will expand when heated, thus reducing the density of the water. Salt will increase the density of the water. It is possible to find some items that would float in cold water, but not in boiling water without compensating with something like salt.