Balloon Lego Cars

Inspired by my new book titled The Unofficial Guide to Learning with Lego, today Lego Club hosted its very first structured session! The topic was balloon powered Lego cars.

The session began with twenty minutes free play before I sat down with the children to talk about what we would be doing. We began with the simple question: what happens when you blow up a balloon and let it go? The air comes rushing out of it and the balloon is propelled forward. For every action there is an equal and opposite reaction.

Working with this principle the children were encouraged to build their own Lego cars. They had to think about the design and what shape, weight and style of car might work best when propelled by a balloon. The activity tested out their engineering skills and helped them to understand the power of air pressure.

We very soon had our first models. Once a balloon had been attached to each car they were lined up at the start of our very sophisticated race track, (marked out using red electrical tape) and...Ready, Steady, Go!!


Sadly, as with all great experiments, it took a few attempts to perfect our machines! On this first attempt, Arrabella's balloon simply deflated without any movement from her car and Wren's stayed inflated just long enough for Remy to attack it! It gave us all a giggle!

Jenson and Ned were next and whereas Jenson's car faired much the same as the girl's cars, Ned's shot off like a rocket! There was much cheering from his team! The losers scratched their heads and thought about how to improve their cars. Whereas Jenson's car had been very light, Ned's had been much heavier so we bulked Jenson's up.

Jenson and Ned raced again but this time neither car moved, despite Ned not making any changes to his! This led to much brain racking by everyone as to what elements of the cars were affecting their performance. Arrabella's Mum suggested weighing all the cars to see if weight had been a factor. They all weighed much the same.

Next we thought about the design. Ned took the wheel arches off his car. The thinking behind this was that the wheels might be getting caught on the arches and therefore hindering the car's movement. We also considered the position of the balloon. Some of us had it higher and others lower. Also, the handle which the balloon end was threaded through was positioned on the back of some cars and at the front of others. We all tinkered around with our designs and tried again. Still we had no luck. The balloon either got caught up in the wheels as the car moved along or the car didn't move at all!

Ned and his Mum started to use bigger wheels and even added a Lego turbo booster to the back! The competition in the room was rising rapidly! This worked really well for them and again, Ned's car was the one to beat. Jenson, being a sore loser, was most disgruntled and so together we tried to create a winning car. We removed the wheel arches, upped the height of the balloon and put a plate at the front to stop the balloon from getting caught in the wheels.

It was a tense moment. Would the changes make any difference? Would we finally have a competitive car that actually moved! Jenson held his nerves at the start line. If he was nervous, it didn't show. On the count of three, he released and the car shot off quick as lightening!!! He was over the moon!!! I very quickly went from inept Mummy to best Mummy in the whole wide world, as Jenson told me in his own words!!!

It was a super morning. Kids and grown ups all had a brilliant time perfecting their designs. By the end of the session though, Wren and Arrabella had lost interest entirely and preferred instead to simply play with Lego the old fashioned way! Next week we are doing ice excavations and sensory bins. Watch this space!