Generally speaking, we try to restrict the use of plastics but some plastic water bottles have been lying around in the house from before. I decided to use them to let my kids build a toy car and learn some basic concepts of physics along the way. Both of my children loved the idea and were willing to make their own plastic bottle toy car, so they could compete against each other. During the construction process, we talked about axles and wheel and how a basic plastic bottle toy car if filled with concepts of physics and engineering. It was fun to build the toy car and kids enjoyed playing and racing them around.
Materials for Plastic Bottle Toy Car
- Empty plastic water bottle
- Cardboard or 4 plastic bottle caps
- Plastic Straws
- wooden skewer
- Hot Glue gun or clay
- pom pom, pipe cleaners, googly eyes for decorating
Body of the Car
- Drill two set of holes into opposite side of the bottle. One set near the neck of the bottle and one set near the end of the bottle.
- Each set of hole has to be in parallel to each other.
- These are the holes where the axles will go.
Axle of the Car
- Take two straws and cut each one so that they are slightly longer than the width of the plastic bottle.
- Pass each straw piece through the two set of holes all the way through on the other side.
- Measure and cut the wooden skewers, so they are a little longer than the length of the straw
- Slide each skewers through the straws. These are going to be the axle of your car.
Wheels of the Car
- Cut four circular discs from the cardboard. They are going to be your car’s wheel.
- The circular discs must be large enough to hit the floor when an axle is mounted in their center.
- Poke holes in the center of each of the circular discs.
Assemble the Car
- Install each of the four cardboard wheels center to the ends of the skewers.
- Place a little hot glue or clay where the skewer and the wheel meet to get the right snug fit when putting the skewer in the wheel.
- Roll the car to ensure the wheels are able to move freely.
- Decorate your car with pom pom, google eyes, pipe cleaners.
- You are now ready to roll.
The Science Behind it
Making a toy car gives you the chance to understand one of the six basic simple machines – the wheel and the axle. The wheel is the large rounded part and the axle is the smaller rounded rod. The wheel and axle is a simple machine form that makes moving, pushing , or pulling objects over a distance easier. The axle is placed in the center of a wheel, set in place or able to rotate. The wheel rotates around the axle. Wheels and axles work by rotating the wheel around an axle to move objects horizontally.
On the first try, you may find your car isn’t working perfectly, especially if its axles aren’t parallel or the wheels wobble. If there is too much friction it can cause the wheels to get stuck. Test your car to ensure the wheels spin freely, and the car rolls easily when you give it a push. If not, you may need to make some adaptations to your design.
Try looking at the bottom of a toy car to discover how a toy car travels and you will find two axles and four wheels. May be you can even take it apart to have a closer look.
Can you modify your plastic bottle toy car to be propelled using a rubber band or a balloon.
I have been doing some science experiments with my kids lately, so please make sure to check them out here.
Here are some of my latest blog posts
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