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Explore and Play: Leaky Cups

What happens to water in a leaky cup? 


  • 6 paper cups, each with different “leaks,” made with a pin. The small holes should allow water to drip out in drops. The larger holes should create a thin stream of water.   
    • cup with one small hole at the bottom
    • cup with one big hole at the bottom
    • cup with 3 small holes down the side
    • cup with three big holes down the side
    • cup with small and large holes down the side
    • cup with many small holes on bottom and sides
  • container or bucket to catch leaks
  • container of water
  • chart paper

Key Science Concepts

  • Water can flow quickly or slowly.


Encourage children to use words related to water such as water drop, drip, and leak, along with science process words such as observe, compare, same, different, change, test, and predict.


Tell children that they’ll look at some cups with leaks in them.

  1. Show children the cup with one hole at the bottom and ask them where they think the cup will “leak.”  
  2. Hold the cup over the bucket and then have a volunteer add water. Discuss what happens. Draw the cup on the chart and have children indicate where the water came out and what it looked like.  
  3. Then repeat the process with the other five cups. As you test the cups, ask:
    • How is the water coming out of the cup?
    • What does the leaking water coming out of the holes look like?
    • What’s different about the water coming out of the sides and the water coming out of the bottom?
    • What’s different about the streams of water coming out of big holes and little holes?
    • What happens as the water empties out of the cup? 
    • What might happen if you put your finger over one of the holes? Let’s try it.

Tell children that you will add the cups to the Mini Water Center so they can experiment further with leaking cups during learning center time.