Why is it a physical change to freeze water?

A temperature change occurs.
Heat is released during the process.
Only a phase change occurs.
The new and original substances are different.

1 answer

Freezing water is considered a physical change because:

  • Only a phase change occurs.

In this process, water transitions from a liquid state to a solid state (ice) when the temperature drops below 0 degrees Celsius (32 degrees Fahrenheit). However, the chemical composition of water (H₂O) does not change; it's still the same substance in a different state. The other statements, while they describe aspects of the freezing process, do not accurately define why freezing is classified as a physical change.

  • A temperature change occurs (true, but does not define a physical change).
  • Heat is released during the process (true, but also does not define a physical change).
  • The new and original substances are different (false, as the substance remains H₂O).