SINK AND FLOAT (collective presentation)
To encourage the child to explore whether different objects sink or float.
To lead the child to simple classification.
Twelve objects, some which float and some which sink, contained in a box.
A shallow bowl, jug, drying cloth and tray.
Invite a child to join you and have him carry the material to a table.
Arrange the materials neatly and in order of use.
Have the child almost fill the jug with water and pour the water into the bowl.
Select an object.
Child identifies it; if unable, give him the name.
Give the object to him to feel and explore.
Discuss if it is heavy or light, small or large.
Gently drop the object into the water.
Observe if it floats or sinks. Remove the object.
Place it to one side.
Repeat the procedure for a contrasting object, only this time place it to the other side.
Repeat for the remaining objects.
Encourage the child to guess whether they will sink or float.
Sort the items into the two designated areas. When finished empty, dry and replace the materials.
As in presentation.
Change the objects frequently.
Gently drop a ball of plasticine into the water, watch it sink, then shape it like a bowl and watch it float.
Invite the child to manipulate the plasticine and see if it sinks or floats.
Compare the buoyancy of salt and fresh water.
Fill two identical containers about two-thirds full of water.
Add salt to the water in one container, a tablespoon at a time and stirring vigorously until no more salt will dissolve.
Get two large ice cubes the same size, put one into each container.
Note which ice cube protrudes the most from the water.