Initially the children were asked to put together their Lego car and push it, with themselves as the force, across surfaces such as carpet, wood and plastic. They then modified their cars to see if they could make them go further. Most groups took parts off their cars to lighten them.
Finally they were asked to modify their cars to see whose car could go furthest down the ramp outside the staffroom. There was a catch! They were not allowed to push their car. They had to find another force that would propel their car down the ramp, with interesting results.
Here is the video of the race: