Question: how much thermal energy is in water?
Answer: One of water's most significant properties is that it takes a lot of heat to it to make it get hot. Precisely, water has to absorb 4,184 Joules of heat (1 calorie) for the temperature of one kilogram of water to increase 1°C. For comparison sake, it only takes 385 Joules of heat to raise 1 kilogram of copper 1°C.