My children love exploring track marks, it really appeals to there inquisitive minds. I was hoping to do this outdoors today so we could get a bit messier but the weather was a bit of a let down. Instead we taped brown paper to the top of the dining room table.
We then rolled the cars through the paint and pushed them across the paper to discover what kind of track they left.
When we do this outdoors we usually sent up a car wash using a tray of shaving foam, a ramp, a bucket of water, and a few plastic cups and funnels. Next time we get to do this outdoors I will share pics.
Sometimes we play detectives. I tell them a little story about a robbery or crime that took place and the only clue is this track mark I found outside. I show them a picture of the track mark and their job is to find out who committed the crime by finding out which car has a track that matches the one from the scene of the crime.