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Gently Down the Stream

Make a stream outdoors and discover what floats down it. 


  • a sloping area of blacktop or dirt
  • water containers (plastic buckets, bottles, and cups)
  • garden hose (optional)
  • digging tools and sticks
  • a few indoor materials: pieces of Styrofoam, cups, straws, ping pong balls
  • outdoor materials that children collect: twigs, leaves, seed pods, etc.

Key Science Concepts

  • Objects behave differently in water. Some float; some don’t.


Introduce the words shallow and deep. Encourage children to use the words sinking, floating, and stream, along with science process words such as observe, notice, compare, same, different, change, test, and predict.


Tell children that they’ll go outside to make a stream and try floating different things down their streams.    

  1. Have children collect outdoor materials such as twigs, leaves, and seed pods.
  2. Then bring children to a sloping area of dirt or blacktop and have them work in pairs to build a stream. 
  3. Have them try floating different things down the stream (the indoor items and the ones children collect outside). Ask:
    • Which things floated the best? Why do you think that was so?
    • Which things didn’t move down the stream? Why do you think so?
    • What things got stuck? Why do you think that happened? (Children might say the object was too big, too heavy, etc., or the water was too shallow.)
    • If you could make your stream deeper or wider, do you think more things would have floated? Why?
  1. Take photos or videos of the streams, which you can look at together later.

Reflect and Share

Point out that this activity used flowing, or moving, water. Then ask:  

  • If something floats in still (not moving) water, do you think it will also float in moving water?
  • If something sinks in still (not moving) water, do you think it will also sink in moving water? 

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