# Water-Saving Shower Questions

Answer these questions on a piece of paper. You will need a calculator!
 Show that the calculations for water volume ranges for five minute showers in the first paragraph are correct. Is there any evidence of bias in this advert?

Andrew is sceptical that the design can be as effective as a normal shower when using over 75% less water. Yet he likes the design and needs a new shower head anyway, so decides to try it out.

When the new shower head arrives, Andrew conducts an experiment to test the claims made. He finds a 9 litre bucket and a stopwatch. Using the old shower head, he times how long it took to fill the bucket with the hot tap on full. He then repeats the test having adjusted the water to a comfortable temperature. Finally Andrew repeats both tests with the new shower head in place. Click for his results:

 What are the independent and dependent variables in this experiment? How might Andrew have ensured that this was a fair test? Why have the times been indicated as an average? Would it have been useful to have used a stopwatch with greater sensitivity? Andrew's shower seems to have a lower pressure than the range suggested in the advert that are used for comparison. How likely do you think it is that other people would achieve the 83% savings indicated in the advert?

Andrew and his wife are satisfied by the shower and recommend it to friends and family as a useful way of reducing energy and water use, saving them money and helping limit their impact on climate change.

This showerhead wins the GCSE.com How Science Works efficiency award and is highly recommended.
 How confident would you be in accepting their recommendation and purchasing an EcOxygen to lower your fuel and water bills?