Simple Machines experiment: test self-locking screws


In Simple Machines, kids twist a set of screws to lift and hold up a trio of sloshing fish tanks. In this activity, you can test the self-locking abilities of screws by seeing if water splashes out of a container when dropped.

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Download and print the activity here.

You need:

  • 2 plastic bottles, 1 with a screw top and 1 with a push top (if you can’t find a push top, get 2 screw tops)
  • water (to fill the bottles)
  • clothes that can get wet

Test self-locking screws

  1. Fill the water bottles.
  2. Push the top closed on one bottle and screw the top closed on the other.
  3. Go outside!
  4. Drop the bottles.

Which bottle stays shut and which bottle bursts open?

This activity was designed to further learning in the Simple Machines app. Find more activities to support your kids’ learning in the Simple Machines Handbook.