Hot food contains more heat therefore more energy. Does this mean that it will give more energy to whoever eats it or just make them temporarily hotter by heating them on the inside?

It has become "common knowldege" in my SCUBA club that a huge number of calories are used on a simple dive. It makes complete sense that the effects of cold water (as low as 7 C) would lead to an increased rate of metabolism but the member are adamant (particularly the Drysuit divers) that the increased pressure of gases in the system is the main cause. 

So does the pressure effect of SCUBA diving have an effect on energy consumption, if so how?

If you remove a large number of electrons (in the order of 1E4 per mole) from a metal, would this affect its melting point in any way? Therefore would it be possible to use a Van der Graaf type generator running on renewable sources to lower the energy requirements on an industrial scale?

I tried searching in many different sites, and yet I have a difficulty understanding what is electron excitation, in particular - how do electrons manage to alter their energy levels? Could anyone please recommend me some useful links on this subject?

Thank you in advance

magnets are a free source of energy (potential energy from attraction or retraction) that lasts forever, couldnt magnets be used to generate energy for example to power a car?

I've heard that most of the earth's energy comes from the sun (oil, wind, solar etc). Where does the rest of it come from?

I just watch a documentary about the nature of reality (horizon) there seems to be allot of excitement about the Higgs boson that apparently holds the key to mass. however I think I read somewhere that as a you approach the speed of light you gain mass and I'm sure iv read about mass being gained because of energy. does this no suggest that there is no such thing as mass and in fact mass does not exist and is just a measure of energy?

If you had stood outside looking up with your mouth open in the UK's worst snowstorm in the past 10 years, how long would it taken for the snow to fill your mouth with 200ml of water?

Would it have been more energy efficient to keep yourself warm all that time or to transport that 200ml of water to a tap in the area that the snowstorm happened?

Scientists said that the Big Bang was caused by the conversion of energy into mass, according to Einstein's E=mc2 formula. But where does this energy come from? And what actually triggered the Big Bang?