Monday, October 17, 2011

Sail cars

J was getting antsy and instead of letting him destroy the house, I decided to build him a quick sail car.

And then he played around with it, even naming it "Lightning McQueen."  My only guess for the name was due to how fast it went!  Here's a video demonstration.  Have your child blow as though they are blowing out candles on a birthday cake.

Main take away from lesson: for every action (blowing on the sail) there's an equal and opposite reaction (the car moves!).

Here's how you can make your own sail car out of recyclables.

  • Cardboard box (non-corrugated) - I used an empty contact solution box
  • 2 wooden skewers (for kabobs, or in our case, chocolate fountain dipping)
  • Masking tape
  • Scissors

  • Cut out the bottom of a box (keep it intact so you don't have to assemble a body of the car).
  • With the remainder of the box, I cut a sail and 4 circular wheels (I used small playdough containers to trace my circles).
  • Very carefully cut your skewers to a size where they'd make good axles for the car - cut off the pointy side too, for safety, while you are at it.
  • With the pointy side of the skewer, puncture your circles in the middle of the circle (don't hole punch these - you want them to be a tight fit on the skewer so they roll/move with the axle).
  • Attach one wheel to each circle.
  • Single hole punch 4 holes for the axles - 2 in the front and 2 in the back (make the holes relatively straight across from each other).
  • Insert the axles and attach the other wheels.
  • Position your wheels so they aren't touching the side of the car (friction) or falling off of the axles.  You want them to be as straight as possible.
  • Tape the ends of your axles, so your wheels don't pop off.
  • With left over skewer parts (axle "rejects"), tape a piece of skewer to your sail and attach it to your car.  I found masking tape works best.
  • Mark and X or put a sticker where you want your child to blow if they are having problems directing their sail car.

This to play around with
  • Shape of the sail
  • Direction of the sail
  • Where to blow on the sail (use a mini fan if your child can't blow hard enough)
  • Weight in car
  • Weight of car (downsize if it's not working)
  • Race your car(s) - who can go fastest/furthest with one blow?
  • Navigate your car through a maze
  • Decorate your sail car (not sciency, but keeps them out of trouble for a few more minutes and make it theirs)

I'd love to hear feedback of how your home sail car project went.


  1. This is very cool! I didn't expect the car to move as quickly as it did!

  2. Hi MaryAnne. Thanks for reading Nerdy Baby. To ensure the fastest race sail cars, make sure the axles can freely rotate within their holes, which is why I recommend a hole punch sized hole. Also, you can be more careful than I was in cutting out the circles for the wheels (I was losing J pretty quickly). My husband suggested using the Cricut (currently gathering dust), but maybe he was thinking if I make them for J's school, which I might do soon.