Slip Sliding Away

This activity shows the children that water makes surfaces slippery. After the activity, talk to the children about safety in the bathroom and kitchen – tell them not to spray water over the floors, since others can slip and fall and hurt themselves.

Materials

• A smooth plastic board about a metre long 
• A small rectangular block (wood or plastic)
• A bucket of water
• A mopping cloth

Procedure

1. Place the block on the dry board
2. Give the block a sharp tap and see how far it goes
3. Now wet the board properly
4. Place the block on the wet board (you can wet the block too)
5. Give the block a sharp tap and see how far it goes

Does it move more easily and does it move further? Why?

1. You could also do this activity by holding the board at a slight incline and placing the block on the top.

Do you need to push the block down when the board is dry?
Do you need to push the block down when the board is wet?
Why?

Note for the teacher
A simple explanation on friction can be given to the students. Ask them to compare the degree of difficulty of walking on loose sand and on a wet surface. Compare also a wet road and a wet tiled surface.