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Active Time
20-30 minutes
Total Project Time
20-30 minutes
Key Concepts
mass, center of mass, balance, physics
Plastic bottles filled with colored water arranged in a pyramid shape


Have you ever played a game at a carnival, trying to win a stuffed animal or other prize? It might look easy, until you try it. Why are those "simple" games at the fairs and carnivals so hard? Is it really lack of skill or coordination or do those concessionaires use some basic laws of science to help them set up the games in their favor? In this science activity, you will investigate how physics can help you win — or lose — at the classic game of trying to knock over a pyramid of milk bottles using a ball.


Teisha Rowland, PhD, Science Buddies
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Masking tape, a stick, a rock, or a similar object to mark off a throwing distance
  • Tennis ball or baseball
  • Plastic bottles filled with water, all of the same shape and size (3). Make sure that you can stably stack the bottles in a pyramid shape. Most 16.9 fl. oz. drinking water bottles should work well for this.
  • A very large room, or an area outside, with plenty of space so you can throw a ball without injuring someone or breaking something
  • A small, stable table
  • Optional: Food coloring



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Active Time
20-30 minutes
Total Project Time
20-30 minutes
Key Concepts
mass, center of mass, balance, physics
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