Physical change introduction and reversibility

Introduce physical changes (part of chemistry curriculum) with four simple stations. Students discuss whether the physical changes are reversible or not.
Science content
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Lessons activity is in
  • pieces of scrap paper
  • balloons
  • tubs of marbles and gravel, and sieves (hole spacing that catches the marbles and allows gravel to pass)
  • pencil and pencil sharpeners

Set up four stations for students to visit:
1. Pieces of paper that they can crumple and tear
2. Balloons that they can blow up, then deflate again
3. Students mix marbles and gravel together, then try and separate again using the sieve
4. Pencils that they can sharpen.

Students can use a worksheet (attached) to record whether they think each physical change is reversible or not. This is not always obvious and will lead to some interesting discussion.

Physical changes are, by nature, are usually technically reversible because the chemical composition has not changed, only the shape or how it is organized with other materials has changed. But is it not obvious how a torn piece of paper can become one piece again, and students can decide whether each of the situations are reversible.

Grades taught
Gr 2