Physical Change
A change that alters the form or state of a substance while leaving its chemical composition intact.
Unit
Dimensionless
In depth
No bonds between atoms are broken or formed; only intermolecular forces are overcome, so the change is usually easy to reverse. Mass is conserved, and the original substance can be recovered by reversing the conditions. Changes of state, dissolving and grinding are all physical.
Examples in the real world
Ice melting to water, iodine subliming to a violet vapour, sugar dissolving in tea, and copper being drawn into wire.