# Will the mass of a stick of dynamite be conserved when it is exploded?

If a stick of dynamite is blown up in a hermetically sealed chamber, the mass of the chamber and fragments, the heat, sound, and light would still be equal to the original mass of the chamber and dynamite. If sitting on a scale, the weight and mass would not change.(Wikipedia)

I was wondering if the chamber cooled down, lost heat, and since energy is equal to mass, will the mass of the chamber decrease?

• What do you think? – Bob D May 15 at 11:45
• I thought so, It would decrease. But the total mass would be conserved since the energy released will be absorbed by the surroundings again adding to the mass of the surroundings. – Sykhow May 15 at 11:51
• It takes a lot of energy loss to make a noticeable mass difference. Eg, 1 kw for a day is just under a microgram. – PM 2Ring May 15 at 11:58

$$E =mc^2$$ and see for yourself