What children will learn
- Explore how slope and gravity affect speed
- Design, test and improve a structure
- Measure and compare times
You'll need
- Cardboard tubes (paper towel and toilet roll tubes)
- Cereal boxes or other thin cardboard
- Masking tape or painter's tape
- Marbles (or a small ball)
- Scissors
- A timer
Safety first
- Marbles are a choking hazard — keep them away from babies and toddlers and count them back in afterwards.
- An adult should help with cutting cardboard, and use low-tack tape so walls aren't damaged.
- Don't stand on chairs to reach high spots without an adult holding them steady.
How to do it
- Cut some tubes in half lengthways to make open chutes (an adult can help with the scissors), and keep others whole as tunnels.
- Tape the first piece high on a wall, door or the side of a bookcase, sloping gently downwards.
- Add pieces one at a time, testing with the marble after each addition so you find problems early.
- Once the marble reaches the bottom, time its full journey.
- Now improve: change slopes, add zig-zags or drops, and see if you can make the run take longer without the marble getting stuck.
Make it easier
Build a short run on a slope against a couch or box using four or five pieces.
Make it harder
Add a challenge: the marble must change direction at least five times, or land in a cup at the end.
Parent tip: When something doesn't work, ask 'what could we change?' rather than fixing it for them — the redesign is the engineering.
Fantastic work! Every little step helps you grow.