Reversible and Irreversible Change

Chemical changes...

• Always form a new substance.

• May change shape or size.

• May absorb or release heat.

• May change colour, produce odor, create sound, release gas or produce light.

• Can often be undone.

Physical Changes...

• Do not form a new substance.

• May change shape or size.

• May absorb or release heat.

• May change state of matter.

• Can often be undone.

Leaves in autumn undergo a chemical change.

• TRUE

• FALSE

Fireworks exploding in the sky undergo a physical change.

• TRUE

• FALSE

Choose the answers that respond to a physical change.

• Burning wood.

• Chopping wood.

• Melting ice.

• Rotten bananas.

Choose the answers that respond to a chemical change.

• Fireworks.

• Cutting fabric to make a dress.

• Making a cake.

• Chopping onions.

Mixing and dissolving are examples of reversible change.

• TRUE

• FALSE

Rusting is an irreversible change.

• TRUE

• FALSE

Tick the three main things you need to start a fire.

• An extinguisher.

• A fuel.

• Oxygen.

• Ignition.

When talking about fire extinguishers, the acronym PASS means...

• Pass - Aim - Sweep - See

• Push - Aid - Spray - See

• Pull - Aim - Spray - Sweep