This STEM activity can be used to demonstrate the difference between potential energy and kinetic energy to children.
- Basic engineering / model building skills
- Discussing energy types
- Finding out about hydro power
- To understand forces
- To introduce the concept of renewable energy
What You’ll Need:
- A foam ball
- Acrylic paints
- A glue gun
- Some wooden BBQ skewers
- Coloured felt pens
- A permanent marker
- Masking tape
- A bamboo cane
- Some used plastic dessert container pots
Important: Some aspects of this activity should be done by an adult, or under strict supervision – especially when working with a hot glue gun or using the wooden skewers.
Making the water wheel
To begin, wrap a strip of masking tape around the full circumference of the ball.
Then remove the tape from the ball and with a pen and ruler, draw a horizontal line across the centre of the tape. Draw another line at the top and one at the bottom (around the same width as a ruler). Next, mark 8 vertical columns of equal width onto the tape and then wrap back around the ball so that the two ends meet up.
Using a wooden skewer, very carefully make some small pilot holes in the intersections on the tape, but not the ones along the middle line. This will be where the pens go that hold the plastic pots. Do this all the way around (you should end up with 16 holes).
Next, we need to find the centre of the ball. This will be where our axle goes to turn the wheel. Do this by measuring the diameter and placing cross at the halfway point. Do the same on the opposite side of the ball.
We decided to add a colourful design to our ball with some acrylic paint, but this stage is optional.
The next step is to add the felt pens to the ball which act as the spokes to hold the plastic pots. Glue gun the tip of a pen and push it firmly into one of your 16 pilot holes. After this, glue the lid of the pen on – we’ll need the extra length to allow the cups to fit on. Repeat this for each of the 16 pens (you will have two rings of 8).
We don’t want to waste perfectly good felt-tip pens, so use some old ones that no longer work!
The following step should be done by an adult.
Attaching the plastic pots
Now we need to make some holes in the plastic dessert pots so that we can attach them to the pens. Very carefully, make a small hole with one of the skewers or a hand-drill near the top of the pot. Then do another on the opposite side. You can now make the holes bigger by inserting a screwdriver – but be careful not to crack or snap the plastic.
Next, take a skewer and measure a length long enough to fit between the ends of two pens, and carefully cut it. Thread the skewer through the holes in the pot and glue them into place onto the pen tops.
If you need to, you could hold the skewers in place with masking tape while you attach them.
Now repeat this step until all 8 of the pots are attached to the STEM water wheel.
Finally, we need to make something for the wheel to sit on, so that it can spin around freely. We used Duplo for this as the axle sits nicely on the notches of the bricks. However, you could build your own columns or balance over a bucket, or even a bath if you have a long enough axle!
Using the water wheel
That’s it… your STEM water wheel project is now ready to use! The wheel can be a great way of demonstrating how potential gravitational energy (the water held above the wheel in a watering can) can be transferred into kinetic (moving) energy as it makes the wheel spin.
For older / more able children, this activity can act as a starting point to talk about how the kinetic energy from the wheel can be used to drive a turbine and be transferred into electricity, which in turn can power everyday things such as lightbulbs. It also offers an opportunity to discuss our environment and how we could make use of renewable energy sources.