Balloon Car Race - Which one is Faster?

A fun-filled balloon car race activity video that gives an insight into the concept of thrust, drag, lift, and friction from the engineers at James Dyson Foundation!

Courtesy: James Dyson Foundation

Do you know about the Bloodhound SSC? Well, it is a land speed racing car, and you would not believe that it is designed to be faster than a speeding bullet! Now, this seems really impressive, but have you ever aspired to create your own racing car? Yes, your balloon-powered car. After all, an inflated balloon has so much elastic potential energy stored within it, and much can be done by using this energy!

Science Behind Balloon Car Race?

According to the third law of motion by Newton, there is an equal and opposite reaction for every action. The same also applies to a balloon car. See, when you are inflating a balloon, it has considerable elastic potential energy stored within it. So, when you let the air escape from the balloon, the force leaving the balloon creates an equal and opposite force that sets your car in motion.

You can also understand this as when you let the air come out of the balloon attached to your car, the elastic potential energy stored within the inflated balloon is converted into kinetic energy. This energy, in turn, sets the car in motion.So, if there is more air in the balloon, its stored energy will yield more kinetic energy, and your DIY balloon car will travel more distance.

Interestingly, the Bloodhound Super Sonic car works on the same principle but on a massive scale. It has two engines. One is a jet engine providing 90 KN thrust, and the other one is an engine from a rocket that provides a thrust of 120 KN.

Now, what is this thrust?

Actually, four forces have an impact on all things that fly in the air, and thrust is one among these. Thrust is the force that moves an aircraft through the air and overcomes the weight of the aircraft. It is the engine that produces the thrust.

Have you ever carefully looked at the wings of the airplane? These are designed to overcome the gravity of the earth as the aircraft is lifted up in the air. The other three forces are weight that acts in a downward direction, lift that acts at a right angle, and drag that act in a direction opposite to that of the motion.

So, you know all the elements that you should consider for creating the best balloon car design. Are you ready? Here are the instructions for the same.

Steps to create the best balloon car design

Raw materials

1 balloon

1 paper cup
2 plastic drinking straws
4 bottle lids with a hole in the center of each
4 small rubber bands
A pair of scissors

Steps to follow

First, take the paper cup and cut it in half lengthways to create the body of the car. It is best to do the same under adult supervision. You can also use a plastic bottle and cut it in the same way as it is shown in the video.
Next, take the pencil and poke a pair of holes near the top and near the bottom in half lengthways. Also, make a hole at the bottom of the paper cup.
Take the two drinking straws and insert each through these holes that you have made in the paper cup.
Now slid the bottle lids in the straws at all the four ends of the straws.
Next, take the four rubber bands and wrap each at the end of each straw. This move is to prevent the wheels from sliding from the straw.
Take the balloon and push it through the hole at the bottom of the cup. Do this in such a way that it lies inside the cup and the mouth is outside the cup.
Now blow up the balloon, place it on the floor, and release your car.
Your balloon car is ready!

Now make two or three balloon cars and set them in motion to have the excitement for the balloon car race!

Observation

Once the race is completed, you will notice that not all balloon cars cover the same distance. Some may stop earlier in comparison to others, which happens because the air might have escaped at a fast pace in some balloons.

How to make a balloon car go the farthest?

You must stop the air of the balloon from escaping before the race starts by putting your finger around its mouth. Also, you can insert a straw inside the balloon so that it can become easier to prevent the air from escaping before the race starts. Choose a smooth flat surface like a wooden or concrete floor to start your balloon car race to reduce the force of friction. Now, this is the resistance to motion in the opposite direction when one surface rubs against another.

However, it is not that a DIY car can only be set in motion with the help of the stored energy inside an inflated balloon. You can also create a car powered by water, and it will be a water jet car!

Interested in more balloon science activities :

Curious case of Xenon Balloon

Static Electricity Experiment with Balloon

Useful Engineering Challenge Cards for Kids

How to create a water jet car?

It is possible to create a DIY water jet car with a two-liter soda bottle filled with some water, four wheels, and a rubber tube connector to the opening of the bottle from where you need to pump air into the bottle. Here, when the air enters the bottle, it bubbles up through the water and creates pressure in the space above the water. As a result, when you stop pumping air into the bottle and removes the pumping valve, water from the bottle escapes from that tube opening and creates an opposite force that propels the car in the opposite direction. Sound’s quite interesting, but should be done only under strict adult supervision.

This video that also featured a water jet-powered car gives a deep insight into the law of motion, drag, friction, gravity, and more about thrust while having loads of fun!

Balloon Car Race – Which one is Faster?