Sorting Physical and Chemical Changes Using Evidence
About this lesson
Children work in pairs to sort twelve everyday changes, such as melting ice or rusting nails, into physical or chemical changes. They practise using evidence like new substances, gas, colour change and reversibility to justify each choice. You need only a list written on the board and scrap paper. It takes about 12 minutes.
- Grade
- 5
- Subject
- Science
- Time
- 12 min
- Prep
- 3 min
Objective
Students will classify everyday changes as physical or chemical and give one piece of evidence for each decision.
Prep
3 min: write 12 numbered everyday changes and 4 evidence clues on the board
Materials
- whiteboard and marker
- scrap paper
- pencils
Steps
- Explain that a physical change alters size, shape or state but makes no new substance, while a chemical change makes a new substance. Point to the clues on the board: new colour, gas or bubbles, heat or light given off, and hard or impossible to undo.
- Read the list aloud: ice melting, paper torn, toast burning, nail rusting, sugar dissolving in water, egg frying, cutting hair, baking soda and vinegar fizzing, chocolate melting, wood burning, banana turning brown, water boiling.
- Have pairs fold scrap paper into two columns labelled Physical and Chemical, then sort all 12 numbers and write one clue word beside each chemical change. Give them 5 minutes.
- Go through the list quickly, asking pairs to show thumbs up for physical or thumbs down for chemical, and invite one pair to give their evidence for any item where the class disagrees.
- Finish by asking pairs to name one new change from their own kitchen or home and say which type it is and why.
Quick Check
Ask each student to tell a partner whether a candle wax melting is physical or chemical, and whether the wick burning is physical or chemical, with one reason for each.
Differentiation
Make it easier: Sort only six of the changes together as a class before pairs try the rest.
Make it harder: Ask pairs to find the tricky items, such as sugar dissolving, and explain how they could test whether a new substance really formed.
Good For
- Review
- Supply teacher
- Before lunch
- End of day
