I am doing a lab in which I have to come up with my own procedure. The lab involves putting a hot metal into water, then using calorimetry calculations to find the mass of the metal. (The metal is hotter than the water). What I don't understand is how you know when to stop taking the final temperature of the water + metal mixture. I would assume it's when the mixture has reached thermal equlibrium. But at that point won't the whole mixture lose heat to the surroundings because the calorimeter isn't perfect? So how do I know when it's reached thermal equilibrium if it will always be losing heat to the surroundings? Also on the list of materials, it says "reggae". Nothing in the dictionary besides reggae music. Any ideas?