You’ll need

  • An empty, clean 2 L plastic bottle
  • Scissors
  • A drinking straw
  • A bamboo skewer
  • A piece of thick cardboard (about 10 cm by 10 cm)
  • A sheet of A4 construction paper
  • A ruler
  • A compass (for drawing circles)
  • A sharp pencil
  • Sticky tape
  • A hair dryer or fan

What to do

Warning!

Ask an adult to drill or cut the holes in the plastic bottle for you. When you use the hair dryer, be sure to use a cool setting so you don’t burn your fingers.

  1. The plastic bottle will be the tower for your wind turbine. Make 2 holes through 2 opposite sides near the top of the bottle. Make sure the holes are large enough to fit the straw through.
  2. Cut the straw so that it is about 15 to 20 cm long.
  3. Push the straw through the 2 holes in the plastic bottle, then put the skewer through the straw. The skewer should stick out of the straw a few centimetres at each end.
  4. Use your compass to draw one 7 cm circle on the cardboard and another on the construction paper. Mark the centre of each circle. Cut out both circles.
  5. Fold the paper circle in half, then in half again. Unfold it and place it over your cardboard circle.
  6. Using the paper circle as a template, mark the centre of the cardboard circle. Also mark points every quarter of a circle around the edge. These are your quarter points.
  7. Draw a 2.5 cm straight line from each of the quarter points towards the centre, and cut along the lines. Do not cut all the way to the centre! You can now throw out the paper circle.
  8. Use the pencil to poke a hole in the middle of the cardboard circle.
  9. Poke the cardboard circle onto the pointy end of the skewer. You might need some tape to hold it in place.
  10. Cut 4 rectangles out of the rest of the construction paper, each about 4 cm × 11 cm.
  11. Tape each rectangle to a 5 cm piece of skewer to make the blades. Fold each blade in half lengthways.
  12. Slide the blades into the slots you made in the cardboard circle. Again, use tape to hold them in place if needed.
  13. Blow on your wind turbine. Make the blades turn faster by holding your turbine in front of a hair dryer (on a cool setting) or fan.

Questions to ask

How fast does your turbine spin? How can you measure this? Try drawing a dot at the tip of one of the blades and see if you can count how many times it goes around in, say 20 seconds or a minute.

What happens to the speed of the turbine if you adjust the angle of the fold in the blades?

Can you use real wind power to turn the blades on your wind turbine? Try taking it outside on a breezy day.

Try blades of different sizes and shapes.

Can you think of a material other than construction paper to use for the blades? Give it a try!

What's happening

Wind is created when the Sun heats Earth’s surface unevenly. As hot air rises, cool air moves in to fill the gaps. This process is called convection, and the air movement is wind.

Wind can be a powerful and valuable source of energy. The idea behind a wind turbine is fairly simple. Wind energy turns 2 or 3 propeller-like blades that make up a rotor. The rotor is connected to a shaft. When this shaft spins, it spins a generator to create electricity. A group of wind turbines, called a wind farm, can provide electricity for a small community.

Your wind turbine is a small model of a wind turbine. Engineers use small models to test various wind turbine designs. This is so they can see what works best before spending lots of money to create a full-sized wind turbine.

The shape and size of a wind turbine’s blades affect how fast it spins. Larger blades spin faster than smaller blades. The angle of the blades also makes a difference to the speed of the turbine. If the broad surfaces of the blades are facing the wind head-on, they will be like a wall stopping the wind, and will not be driven around. If the broad surfaces are parallel with the wind direction, the wind will pass straight over them and they won’t be driven around either. The best angle is somewhere between these 2 positions and depends on the wind’s speed and direction.

Did you know

Wind energy is a renewable energy source. There is always wind somewhere on Earth, and people have been using wind power to do work for a long time. Windmills have been used to grind grain into flour or pump water, in the past. Now, modern wind turbines can create electricity.

Most of Australia’s electricity comes from coal-fired power stations. In mid-2022, wind energy was creating about 8.5% of Australia’s electricity. Once a wind turbine is built it does not need fuel and it has zero emissions. A coal-fired power station needs a fossil fuel – coal – to keep working. Fossil fuels are not renewable – there is a limited amount of them in and on Earth.

The wind does not always blow. Electricity generated but not used right away must be stored, which can be expensive. Still, the wind industry is booming around the world. More and more countries are using wind to help generate enough electricity for their growing populations.