LEGO Club Series: Catapults

There is just something gratifying about catapulting something across the room.  Am I right?

This post continues the LEGO club series I’ve been working on. (If you haven’t read my first post on LEGO clubs, this post will give you more information for starting your own club.)  But if you aren’t holding a LEGO club, you still have to try this.  It’s seriously the most fun thing I’ve done with my kids in a while.

The assignment:  Make a catapult that can throw an object.  The object we catapulted was just a small 2 x 1 LEGO piece.  Although, an m&m or small candy would have been fun too!

Along with the usual LEGOs, I set out various sized rubber bands (The Dollar Tree sells a huge package for $1).  We talked for a minute about a few physics principles:

  • Force-  the more force you apply to a catapult, the more speed and distance your object will achieve.  Pulling back further on the catapult adds more force.
  • Angles-  to make it go as far as possible, the angle should be about 45 degrees.  If it is higher than this, it will go high, but not far (which is the goal in this activity).

We then took a minute to explore the tension in rubber bands and how they could possibly help the catapult.  The kids caught onto the idea fast and took off brainstorming their own ideas quickly.

Some of the designs started out simple, but effective:


They eventually graduated to bigger designs with more creative pieces used.


We also set up a testing area.  I put a piece of tape, like a starting line, on the floor.  This was where they tested their catapults when they had a working prototype.  It was incredible watching them try out their catapults and then problem-solve when it didn’t work like expected.


We had ages 5 through 11 building with us and it worked well for all ages.  It would also be a fun activity to get down on the floor one-on-one with your child.  You could really take the time to talk through what makes a catapult work.  And show some full-focused parental attention!

Happy building!


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