Solar energy is another type of natural energy source which is good to familiarise your children with. Since the beginning of the 21st century the solar energy sector has been developing fast (about 40% a year) and is becoming more and more widespread. Before you move on to creating a moving construction which works on solar energy, point out to your children (it would be best to use a globe) that the areas around the equator receive a greater amount of heat energy, contrary to the circumpolar areas. This is because the sunlight strikes these areas at different angles.
WE WILL NEED:
- 3 metal cans
- Adhesive tape
- Drawing pin
- A4 sheet of paper (the best would be greaseproof paper)
- 2 relatively thick books
- A lot of sunshine
Build a tower from the three metal cans (they should be clean, with their lids and bottoms cut out) and put them together into a tube using a tape. Bend a wire (you can also use a wire from a paperclip) and use the tape again to fix it to the top of your tower. Attach a drawing pin at the top of the wire arch. Use the tape again and remember that the sharp tip of the pin should be turned up.
Prepare a pinwheel. Cut out a square out of a sheet of paper. Then, cut the square along its diagonals, leaving the centre of the sheet intact (leave about 6-8cm). Use the tape to attach one edge of the obtained triangles to the centre of the square. Secure the pinwheel upside down on the drawing pin and place the whole tower on two props (e.g. thick books) so that the air inside it can flow freely. Done! Now you have to wait until the air in the cans warms up and starts to lift up, making the pinwheel move. Unfortunately, you need a really strong sunshine for the pinwheel to move, so the best time to complete the experiment would be on sunny summer days.