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Year 9 STEM Challengers Produce Electricity from Water

Four Year 9s put their Science, Technology, Engineering and Maths skills to test in 'The Ultimate STEM Challenge'.

The national competition, sponsored by BP, the Science Museum and STEM Learning, was open for all students aged 11 to 14 from across the UK. Our four students (Jamie, Sam, Jack and Lewin) were asked to choose from one of the three challenges based around the theme of My Sustainable Future and chose to build the 'Handy Hydro' that used moving water to create electricity.

They researched the theory behind it and found out that falling water can turn a propeller-like piece called a turbine, which then turns a metal shaft in an electric generator, which is the motor that produces electricity. They then generated designs to test and developed a sound scientific method to test them, with a testable hypothesis and clear criteria for success.

From various designs of the turbine blades, the students came up with the 2 final designs - one made from foam and the other from wood. They then carefully thought about their variables and tried to find out the rate of the water flow. Identifying the flow rate as 40 ml/sec, they kept the turbine 20 cm away from the tap, connected the motor, generator and the voltmeter and noted down the voltage produced. They repeated each measurements 3 times, dealt with the unusual results, and then took a mean measurement.

They found out that the foam cups were more efficient with a mean voltage of 0.58V, compared to the wooden paddles with a mean average of 0.32V. This was due to the difference in their masses. The cups weighed 2.6g and the paddles weighed 15.3g, altogether making a difference of 12.7g.

They then linked this with the following equation (that students normally study in Year 13 Physics):
F = B (how strong the magnet is) x I (the current on the wire) x L (the length of the coil of the wire). Since the heavy mass results in the turbine moving slower, there will be less force meaning less current is produced.

"It was hard to work together as a team at home, so we planned to work at school during our lunch times and after school. We shared the responsibilities among each other and then collaborated together to complete our project." - Jamie

"The good thing was that our project was working and we could see the voltage being produced.” - Sam

I was really impressed by the level of effort and passion that these students had dedicated to their investigations. They not only used their scientific knowledge, but also their skills in Technology by using a glue gun, cutting dowel etc, in Maths for the calculations and in Engineering to design and build their model. Well done boys!

Mrs Mehta
Teacher of Science