Body mass

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Body mass

Some superheroes can grow to the size of a building at will.

That's very intimidating! But a scientist must ask

where the extra material is coming from. The Law of Conservation of Mass implies

that mass can neither be created nor destroyed,

which means that our hero's mass will not change just because his size changes.

For instance, when we bake a fluffy sponge cake, even though the resulting delicious treat

is much bigger in size than the cake batter that went into the oven,

the weight of the cake batter should still equal the weight of the cake

plus the moisture that has evaporated. In a chemical equation,

molecules rearrange to make new compounds, but all the components should still be accounted for.

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