For Christmas, I was given a Lego chain reactions kit: you use Lego to build machines with chain reactions in them. You can then use several of them to make a line of chain reactions, which could end with a flag popping up, or a ball catapulting across the room. I found these really fun, so I thought I would share them with you.

When you pull out the pin on the first machine, it sets off a swinging tyre that knocks down a hammer. The hammer then pushes on a seesaw, which makes a sign pop up. It also makes a ball roll down a ramp.


The ball then falls into a bucket that is attached to a string looped over a pulley. This makes a block on the other end of the string rise and bump the bottom of another, longer ramp, setting a ball moving down it.


The last machine is a seesaw. The ball from the pulley and bucket falls on to it, making the other end bump yet another ramp, which pushes a ball down a ramp. I was going to use this ball to make a sign pop up, but unfortunately I didn’t have enough bricks to build a machine to do this.


If you have any ideas for future posts, please do not hesitate to tell me! I hope you have enjoyed this post!

PS.If you watched the Royal Institution Christmas Lectures, you will have seen an incredibly long chain reaction – in the lectures, Saiful Islam sets off a Rube Goldberg machine. You can see a video clip of it here: