How does the law of conservation of mass apply to physical changes?

During a physical change, you may change the way that something looks but the total amount of mass will remain the same.

The law of conservation of mass states that when you perform some process, the weight of what you make will be identical to the weight of what you started with. For example, if you melt an ice cube, the weight of the water will be identical to the weight of the ice.

Such is the case with any physical process. You may change the way that something looks when you perform a physical change, but you certainly won't change the amount of stuff present.

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