Water Powered Car STEM Challenge

Talk of sustainable practices are all around us. Environmental sciences have gone from a fringe area of study, to a highly in demand area of expertise. Protecting our planet is so important. We want to find ways to thrive and grow, while also caring for Earth. One of the ways we can do that is by exploring alternative ways of getting around and powering devices. With that in mind, today we are tackling a Water Powered Car. Students will learn about engineering, physics and sustainable practices in this fun hands on STEM project.


Build a water powered car

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A Water Powered Car? Right, you must be dreaming! How is that possible, you ask yourself?

It certainly makes a lot of sense, though. If cars could run on water, we would never have to go to another gas station again, and our environment would certainly have less pollution. No more air pollution, smog, or oil spills in the ocean. Water is generally freely available, so the cost of running a car would be minimal. But how could this work?

Water Fuel Cells

Water is made up of Hydrogen and Oxygen (H20). These two elements can be separated into their individual components.

In the 1980’s Stanley Meyer designed a device he called a “Water Fuel Cell.” Using a process called electrolysis, this device splits the water into the two components: hydrogen and oxygen. Electrolysis uses electricity that is passed through the water to separate the hydrogen and oxygen. The hydrogen was burned to generate the energy to make the car move. He even successfully powered a dune buggy with his water fuel cell.

Stan Meyer died in 1998, but his invention schematics remain on the internet for public use. Many inventors, scientists, and engineers have designed water-powered cars over the years. Most commonly now, car manufacturers are focusing on electric vehicles or, to a lesser extent, hydrogen fuel cells.

Steam Powered Engines

Another way to power engines with water is with steam engines. Steam engines were used in the early days to power trains. In some places you can still see steam engine trains in action. However, the technology was not something that would work for general commuter vehicles.

Water Powered Car the Science

In this fun STEM project, you are going to make a simple water-powered car using materials that you may have lying around your house. And no, you will not be separating the hydrogen and oxygen in the water, but we are using plain old water from the taps in your homes to power your homemade cars!

Our cars will run on a water wheel or turbine. A water turbine is a large wheel with blades or buckets attached to it. The water wheel spins on an axle which is a type of simple machine. The falling water over each blade or from bucket to bucket is the energy source used to power and turn the turbine.

The falling water is potential energy (stored energy) caused by gravity pulling it downward into the buckets or over the blades. This energy is converted to kinetic energy (energy in motion) as the turbine spins.

Water wheels or turbines are simple machines that use the energy of flowing water to turn a wheel, which can power other types of machines.

Water Powered Car Build Video Tutorial

Below is the video tutorial for this project. I always find it easier to watch someone else do a project before tackling it myself with my kids. If you can’t see the video, it is being blocked by your adblockers or firewall. You can also find this video, with closed captioning, on the STEAM Powered Family YouTube Channel.

Project Materials and Tools

6 jumbo craft sticks – colored ones are more fun, or you can paint yours different colors
2 thin wooden skewers
1 thicker wooden skewer

3 old CD’s
12 standard-size soda pop bottle caps
2 slightly larger bottle caps (water bottles or sports drinks often have larger caps)
4 Wooden or plastic beads – optional
20cm of rubber tubing (fish tank or medical tubing)
1.5 or 2 litre soda pop bottle
Disposable cup – It must be about 11cm tall. You can use paper cups; you just can’t see through them like with a plastic cup.
1 bendy drinking strawAlternatives to the straw include using plastic tubing or the body of an old pen. The bendy part of the straw gives you more options for changing the aim of the water once your car is built but it is not required.
Glue gun
Clear Epoxy Glue—This glue is optional, but it held the plastic tubing on the axles better than the glue gun.
Box cutter
Side-cutters or Snips
Awl-to make holes in the bottle caps
Permanent marker

Water-Powered Car Directions

This is the car we are going to build together today. You can see it has 3 wheels, one in front and two in the back.

A water powered car for STEM class

Getting all the pieces ready

If you want to paint or decorate your craft sticks, now is the perfect time to do it. Do not use felt-tip pens as they are water-soluble and the color will run all over.

Turn your glue gun on.

Trim the craft sticks to the proper lengths.

Cut 2 craft sticks to 14.5 cm removing one rounded end.

Cut craft sticks to 14.5cm

Next, cut 2 craft sticks to 9cm removing one rounded end.

Cut craft sticks to 9cm

Cut 2 craft sticks to 9cm removing both rounded ends.

Cut craft sticks to 9cm

Trim all the pieces with a box cutter. SAFETY TIP! Always stand using a box cutter, keeping your fingers away from the blade. Do not use force; rather, make many small cuts and snap the two pieces apart. You may need the help of an adult for this.

Glue the “chassis” or frame of the car together

How to glue the craft sticks together

Place the green stick and then the two red sticks on top of that.

Use a pencil to mark the edges of the red sticks. This is where the glue will go. Glue these pieces together.

Glue the two bottom red sticks onto the green stick.

Next, glue the purple stick over all the red sticks.

The chassis is almost ready!

Make marks on the red stick for the position of the cup with a pencil as shown in the diagram.

Prepare the Cup

Flip the cup over. Using a permanent marker, make marks on either side of the cup, ensuring they are in line and opposite.

Find and mark the middle of the cup (on the bottom of the cup) with a ruler and a permanent marker.

Trace the bottom of the straw over this mark you just made to create a circle the same size as your straw.

Using the tip of the glue gun, make a hole for the straw.

PRO TIP: Always start small. Do not push the nose of the glue gun all the way through. Make a hole and check that the straw fits. If it doesn’t fit, make the hole a bit bigger. Try it again and repeat this step until it just fits. It must fit snugly.

Cut out an archway approximately 6cm tall into both sides of the cup using scissors to cut out the two shapes on either side of the cup. Make small cuts as you go around.

Showing finished cut cup

Place the cup onto the frame where you made marks on the red sticks and trace the sides of the cup with a pencil onto both sticks.

Glue the cup in place on both sides.

Complete the Car Frame

It’s time to add all the other car pieces to the frame.

Cut four pieces of rubber tubing. Two pieces should measure 4cm and the other two 1.5 cm.

I used Epoxy to glue them down as it holds the rubber better, but you can also use the glue gun.

Starting with the side of the short red sticks, glue on the two short pieces of rubber tubing, one on each end of each red stick.

If you are using Epoxy, you may need to find something to lift the frame so that it is level, as it takes time to dry.

Glue the two longer pieces of tubing onto the two red sticks on the opposite side of the frame.
Ensure that they are glued precisely in the middle, on the ends.

PRO TIP: If the tubing is not straight, push one of the wooden skewers through both pieces of rubber tubing and leave it there until the Epoxy glue is dry. You don’t have to do this using the glue gun, as it dries in seconds.

Assembling the Wheels

Let’s prepare and attach the “wheels” and the “turbine” of the car.

Get six standard-size bottle caps. These are for the three “wheels”.

Let’s start by finding and marking the centers of all the caps using a ruler and a permanent marker.

Using the awl and a hammer, make holes in all the caps.

Get the two slightly larger caps, mark them, and make the holes in the center.

Use one of the wooden skewers to stretch all the holes. The skewer should not slide easily through the holes but fit snugly into them.

You may need to do this a few times while putting all the pieces together, as the holes in the plastic keep on shrinking! It can be a little frustrating! You can try using a fatter skewer to do this instead.

Put these caps aside for now.

Glue the two larger caps together with the glue gun. Ensure they are in line with each other. Put glue around the joint on the outside of the two caps to really seal them together.

Get the three CDs. Using the glue gun, glue one bottle cap on each side of the three CDs.

Try your best to line the two caps on either side up. This will make it easier to get the wooden skewer straight. The skewers act as the axles for the wheels and need to be straight to work smoothly.

Put glue around the outside of all the caps. This helps secure them properly.

Assembling the Turbine

It’s time to make the turbine.

Get the two caps you glued together and the rest of the bottle caps in the last step.

Place a small piece of BluTack on the side of all the bottle caps. This will hold them in place while you mark their positions on the caps you glued together. This is an easy way to arrange the six bottle caps evenly in a circle.

Place the six bottle caps evenly on the same side, facing up, around the middle piece.

PRO TIP: Place the first cap and one precisely opposite it on the other side. Repeat this step with the other two pairs of caps, keeping them evenly spaced.

Make a mark with a permanent marker at each bottle cap so you know where to glue them on. Pull the BluTack off and glue each cap in its place. The turbine is ready!

Assemble the Car

It’s time to put the car together.

Stretch all the holes in all the caps. I used a slightly thicker skewer, which I cut much shorter, or you can use the tip of a pencil. Use a circular motion in all the holes. Do this a couple of times. This will make it easier to slide the thin skewers through all the holes.

Start with the two back wheels. Push the thin skewer through the two bottle caps of one wheel and into the first piece of rubber tubing, the turbine, and the other back wheel. Ensure you have equal amounts of the skewer sticking out on each side.


Below is a photo of how it should look. The water from the straw needs to fall into the bottle cap, so all the caps should be facing upward to receive the water.

correct assembly of water powered car

Double-check this before you glue anything else so you don’t make the same mistake I did.

Now that you know the turbine is correct, let’s finish our water-powered car!

Finishing Steps

This step is optional. If you have wooden beads, put a blob of glue into one of the beads and slide it onto the end of the wooden skewer until it just about touches the wheel cap, or trim the skewers and put a blob of glue on the ends.

Repeat this step on the other side. Trim both skewers with a side cutter and put a blob of glue on the ends.

Slide the other skewer through the first rubber tube in the front, the wheel, and the other rubber tube.

Repeat the step with the wooden beads on the back wheels, or trim the skewer on both sides and put glue on the ends.

Base of water powered car

Making the “Gas Tank”

Let’s make and attach the water source.

Remove the cap of the empty 2-litre bottle, find the center of the cap, and mark it with a permanent marker.

Use the straw or rubber tubing to trace the shape onto the cap.

Use the glue gun tip to make a hole in the cap for the straw or tube. Don’t make a large hole. Do it in stages, checking if the straw or tube fits snuggly into the hole.

After the bendy bit, cut off 4.5cm of the straw. If you are using tubing, cut a piece about 7.5 cm long.

Push the straw or tube into the cap so that you can see about 2-3mm of it, and use the glue gun to glue it.

Do not get any glue into the straw or tube! The water should flow easily through the hole into the straw.

Using the box cutter, make a small cut into the bottle so that the “tank” measures about 15cm from the cap. Then, insert the scissors into the cut and cut the cup off the rest of the bottle.

Use scissors to cut off any sharp, uneven edges.

Screw the cap with the straw back onto the bottle to see if all is ok, and unscrew it again.

Push the cap with the straw into the hole at the top of the plastic cup. You may need to make the hole bigger with the glue gun again.

Remove the cap, put glue onto the bottle top and around the straw, and push it through the hole again into the plastic cup. Hold it until the glue dries.

Finally, screw the “tank” into the lid and ensure that it is on tight.

Your water-powered car is ready!

Water powered car

Using the Water Powered Car

Fill another empty bottle with water. Take the car and the water outside (water will fall from the car, so don’t do this anywhere that can’t get wet). Place the car on an even surface, fill the “tank” with water, and watch your water-powered car speed away!

How did your water-powered car work? If it does not move, adjust the position of the straw or tube. The water must go directly into the bottle caps to work.

Extension Ideas

Let all the kids make water-powered cars and have a derby day.

Whose car goes the fastest?

Will a smaller car travel faster?

Will using a different frame make a difference to the car’s performance?

If you change the design to have 4 wheels, do you think it will change the performance?

Build a Balloon Powered Car too, and race them!

Does the “tank” height or size make a difference to the car’s performance?

Use your creativity to create a unique water-powered car. I hope you loved making your water-powered car!

A Brief History of Water-Powered Cars

Francois Isaac de Rivaz was a Swiss inventor who, in 1806, invented and created the first successful internal combustion engine. The engine was powered by a mixture of hydrogen and oxygen. In 1807, he built one of the first automobiles powered by his new engine.

In 1860, Etienne Lenoir of France invented Hippo mobile. The Hippo mobile received its fuel by electrolyzing water and running the hydrogen through the small horizontal engine.

In 1933, the Norsk Hydro Power Company converted one of their small trucks to run on hydrogen gas.

The 1941 GAZ-AA truck was created to run on hydrogen gas because petrol ran low during World War 1. This truck proved that it burned cleaner and longer than those that had run on petrol.

In 1966, Roger Billings used a Model A Ford and converted it to run on hydrogen.

In 1970, Karl Kordesch built a passenger car. It was a fuel-cell hybrid car using seven lead-acid batteries and an alkaline fuel cell powered by hydrogen gas. The car worked on public roads for three years.

In 1972, the Brigham Young Superbeetle was developed by Roger Billings’s team. It was also a hydrogen-powered car.

The first dual-fuel BMW was produced in 1979. It could run on either gasoline or liquid hydrogen.

In 1984, the first Mercedes Daimler Benz was made with an internal combustion engine with compressed hydrogen in Berlin, Germany.

In 2024, many STEAM Powered Family enthusiasts made their first water-powered cars, which proved that cars could run on water!