Students will build a 4-wheel balloon car with the given supplies and try different ways to make the car go further. You can even race to see whose car is the fastest! 

Supplies Needed: 

• Balloon 
• Flexible Straw 
• Tape/Rubber band 
• Water bottle
• Straws/BBQ Skewers 
• Bottle caps (4) 
• Dry sponge

Making the “Engine”  

1. Put the long end of a flexible straw into a balloon.  
2.  Attach the straw and balloon so that no air can escape, using either a rubber band or tape.  
3.  Poke two holes in the bottle’s sides, on the part of the bottle that will be the bottom of the car. Make the holes directly across from each other so the axle goes straight across.  
4. Slide a straw through the two holes.  
5. Adjust so the axle goes straight across.  
6. Repeat for the second axle.  
7. Slide a barbeque skewer through each straw.  

Making the Wheels  

1. Wedge a square of sponge into a bottle cap to make a wheel. Make 4 of these. 
2.  Add the wheels to make it easy to push a skewer into a sponge, use the skewer’s point to poke holes in the sponges. Center the holes so the wheels will spin evenly and not wobble up and down. Push the wheels onto the ends of the skewers.  

Insert the “Engine”  

1. Poke a hole in the top and back of the bottle. Push the jet into place so that the straw’s balloon end pokes out the top and the open end pokes out the back. Make sure the straw at the back is as parallel to the floor or tabletop as possible. If it points up, down, or to the side, your car won’t move as fast or far as if the jet points straight back.  

Power the “Engine” 

1. Blow up the balloon by blowing through the straw. Put your finger over the end of the straw to stop air from escaping. Put the car on a smooth surface. Then let go and ZOOM!