Sink/Float Experiment

A science demonstration which is safe, (almost) always works, and allows kids to be involved. Teacher: Shirley, what do you think this crayon will do in the water? Precocious 4 year old Shirley: Dissolve.



Children ages 5 and up can give the materials that the objects are made out ofCog. I
Children between the ages of 4-5 can help with problem solving: able to detect properties of objects in water will sink or float Cog. I
Children between the ages of 3-4 can use weight to describe an object Cog. I
and children 2-3 can give use of objects by pointing or gesturing Cog. I
And children 1-2 years can identify simple objects Lang. IB


Large fish bowl; familiar objects such as apple, banana, wooden block, small glass, bottle with lid, scissors (metal), paper cup, sponge, plastic toy, wooden toy, rubber ball, pencil, pen, rock, plastic fork, shell, etc. with easily identifiable composition, i.e. wood, food, metal, plastic, stone. (Don't use crayons. Wax crayons float, but pressed crayons sink. It's confusing.)


LANGUAGE TO EMPHASIZE: Sink, float, top, bottom, wet, dry.

1. Seat children in a semi-circle around a small table. Place water on the table. Have all of the objects in a bag.

2. Choose one child to pick an object out of the bag. Ask the other children to name the object, describe its use, and identify the material(s) it's made of.

3. Ask the group to guess whether the object will sink or float. Take a vote and count. Have the child drop the object into the bowl. See if it sinks or floats.

4. Proceed in this fashion, dividing the things that have already been tested into two groups on the table. Help children define classifications by reviewing the compositions of each group of objects. Discuss and compare composition of tested objects with the new object drawn from the bag, e.g. "This toothpick is made of wood and it floated in the water. This block is made of wood, too. What do you think the wooden block will do in the water?"