The best size is a small water bottle. Make sure it’s thoroughly rinsed it out and clean, especially if you’re using a soda or juice bottle.
If your bottle has ribs, use those as a guide. Use strong, sturdy tape, such as duct tape.
You can also trace four circles onto a sheet of cardboard, then cut them out. You can also use buttons instead of bottle caps. Don’t poke holes in them and make sure that they are the same size. [5] X Research source If you’re scared to use a nail and hammer, stuff a small piece of sponge into each bottle cap. [6] X Research source
If you are using buttons, simply hot glue them to the end of each skewer. [8] X Research source If you stuffed the inside of the bottle caps with a sponge, simply slide them onto the skewers. [9] X Research source
Insert the straw bendy-side-first into the balloon.
The straw should bend naturally at its bendy part inside the bottle.
Fill the balloon by blowing through the straw opening at the end of the bottle. Put your finger over the end of the straw once you’re done filling the balloon. When you’re ready, let go of the straw and watch the car go.
Make sure that the carton is clean and dry.
Make sure that you are cutting the smooth part of the straw. Do not include the bendy part.
Make sure that the straws are straight. If they are crooked, your car won’t go straight. Use strong tape, such as duct tape.
If you don’t have any skewers, you can use lollipop sticks instead. Make sure that they can slide into the straws easily.
If you don’t have any bottle caps, you can use buttons instead. You can also cut circles out of cardboard. Make sure that they are all the same size.
Use sturdy tape, such as duct tape. If the straw is too long, cut it down. You want only about 1 to 2 inches (2. 54 to 5. 08 centimeters) sticking out over the edge of the box.
Blow up the balloon. Don’t tie the end; rather, just hold it closed with your hand. When you’re ready, let go of the balloon end and watch your car go!
You can also use foam core. It is the same thing you use for presentation boards. For a fancy car, paint the cardboard with acrylic paint or cover it with duct tape. Let the paint dry before moving on.
Use sturdy tape, such as duct tape. This way, the straws won’t wiggle loose. Make sure that the tape covers the entire length of each straw.
If scissors aren’t tough enough for the job, try wire cutters. If you can’t find any wooden skewers, use lollipop sticks instead. Make sure that they roll around easily in the straws.
You can also use bottle caps instead of cardboard.
If you used cardboard or foam core, you should be able to make the holes using a pen, pencil, or a skewer. If you used bottle caps, you will need to punch the hole using a nail and hammer. Ask an adult to help you.
Use regular balloon, not a water balloon, noodle, heart, alien, worm, etc.
It’s okay if the straw is hanging over the edge of the car. If it is touching the ground, trim it down. Don’t let the balloon hang over the edge. If you do, it will bump against the ground and stop your car from moving. [17] X Research source
The straw is the back of the car. The balloon is the front. If the balloon is not holding air, there may be a gap. Wrap some more tape around the end of the balloon. If the balloon still is not holding any air, it might have a hole in it. Get a new balloon.
