Water play is a continuous provision staple, making it the perfect vehicle for introducing early physics. In this simple experiment, children test everyday objects to see if they float or sink, encouraging them to make predictions, test hypotheses, and use rich scientific vocabulary.

Materials Needed

Large transparent storage tub or water tray
Water and a towel for inevitable spills
Natural items (twigs, pebbles, leaves, pinecones)
Classroom items (wooden blocks, plastic spoons, metal paperclips, sponges)
Two hula hoops or large drawn circles on paper for sorting

Step-by-Step Setup

1. Set the Scene

Gather the children around the empty sorting hoops labelled Sink and Float. Show them the basket of objects. Ask open-ended questions: "What do you think will happen when we put this heavy pebble in the water?"

2. Make Predictions

Before touching the water, hand objects to the children so they can feel the weight. Ask them to place each item into the Sink or Float hoop based on their guess. Emphasize that scientists love making guesses, even if they are wrong!

3. The Big Test

Move to the water tray. Invite children to take turns dropping one item at a time into the water. Narrate the action using rich vocabulary: "Look at the wooden block, it's staying on top. It has buoyancy! It floats."

4. Sort and Discuss

After testing, pull the items out and re-sort them based on the actual results. Discuss the surprises. Address common misconceptions: "The sponge is big, but did it sink straight away? What happened when it filled with water?"

5. Independent Exploration

Leave the sorted trays and water tub as continuous provision for the week. Let children independently test new items they find in the classroom. "I wonder what else we can find that floats?"

Classroom Adaptations

Large class?

Run this as a small adult-led focus group of 4-6 children while others engage in continuous provision.

Limited resources?

A standard washing-up bowl works just as well as a large tray. Use recycled bottle tops and stones from outside.

Mixed ages?

Younger children can focus on the sensory aspect of dropping items in, while older children can articulate their reasoning.

High ability?

Challenge them to record the results independently using a simple tally chart on a whiteboard.

Will It Sink or Swim: Floating and Sinking Science Activity for Reception