Building a wind-powered car from a plastic bottle is a fantastic way to explore physics and recycling at the same time. There are two popular ways to do this: a propeller-powered car (which uses a rubber band to spin a fan) or a sail car (which catches actual wind from a fan or the outdoors).
Materials You’ll Need
- Chassis: One empty plastic water or soda bottle.
- Wheels: 4 plastic bottle caps.
- Axles: 2 bamboo skewers or wooden sticks.
- Bearings: 2 plastic straws (cut to be slightly shorter than the skewers).
- Power Source:
- For a Propeller Car: A second bottle top (for the fan), rubber bands, and a paper clip.
- For a Sail Car: A piece of paper or cardboard and an extra skewer for the mast.
- Tools: Scissors, a hot glue gun, and a marker.
Step-by-Step Instructions (Propeller Version)
- Prepare the Axles:
Cut two pieces of straw slightly narrower than your bottle’s width. Glue them horizontally across the bottom of the bottle (one near the front, one near the back). These will hold your axles and allow them to spin freely. - Attach the Wheels:
Poke a small hole in the center of each bottle cap. Slide a skewer through one straw, then push a cap onto each end. Secure the caps with a dab of hot glue so they don’t slip off the skewer. - Craft the Propeller:
Cut the top off a second plastic bottle. Cut 4–6 slits from the rim down toward the cap and bend them outward to create blades. Poke a hole in the center of this cap. - Install the Power System:
- Straighten a paper clip and bend one end into a hook. Feed it through the propeller cap and secure it.
- Cut a window in the middle of your main car bottle.
- Hook a rubber band to the propeller’s paper clip inside the bottle and anchor the other end of the rubber band to the front of the bottle (you can use another paper clip or a small notch).
- Let it Zoom:
Spin the propeller manually to wind up the rubber band. Once it’s tight, set the car on a flat surface and let go!.