DIY balloon car: Nurture your youngsters’ interest in STEM with this fun activity 

There are various DIY activities and experiments that foster STEM learning in kids. Today, we are here with a DIY STEM activity named balloon car making, that emphasises on reuse and recycling. This activity will help your kids understand the physics concepts of potential energy, kinetic energy and Newton’s laws of motion.  

What you’ll need 

• Plastic bottles 
• Bottle caps 
• Flexible straws 
• Wooden skewers 
• Balloons 
• Rubber bands 
• Duct tape 
• Scissors 
• Knife 

How to 

Here are easy-to-follow steps for this STEM activity. Help your kids follow these. 

• The first step is to cut the two straws using the scissors in such a way that they are slightly longer than the width of the bottle. 
• Next, tape the straws to the bottle keeping the same gaps in between using the duct tape. The goal is to keep them parallel. 
• Now use the knife to cut the skewers. Make sure they are slightly longer than the straws. 
• Take 4 bottle caps and use the knife to make small holes in the centres.  
• Now, put the skewer through one of the holes and thread it using one of the straws. 
• On the other end of the skewer, push a bottle cap. This will make the structure look like an axle with two wheels. 
• Repeat the same steps to make another axle. The goal is to ensure that the axles spin properly and they are well-aligned.   
• Now, take a third straw and slide it through a balloon and firmly wrap two or more rubber bands around its neck. 
• At this stage, use the straw to blow up the balloon. The goal is to ensure that there are no leaks. 
• Cut the small hole at the top of the car and push the free end of the third straw through the small hole and out the mouth of the bottle.  
• Finally, inflate the balloon, put the car down and release. The more the balloon is inflated, the faster the car will move. 

The science behind the experiment 
In this experiment, the inflated balloon stores potential or static energy which is converted to kinetic energy (energy of motion) as soon as the balloon is released.  

Newton’s first law of motion states that an object in motion will stay in motion or an object at rest will stay at rest, unless acted upon by an external force. This is revealed in this experiment when the balloon car keeps moving forward even when the balloon is deflated, until an external force brings it to a halt.  

Also, Newton’s third law of motion states that for every action, there is an equal and opposite reaction. Here, this is proven when the balloon deflates, the air escapes through its back, that in turn pushes the car forward.