What it shows
You measure how much water each daily activity uses by counting buckets, mugs and tap flows, and then work out litres per person per day. The result helps find where water can be saved.
The science
Volume is measured in litres, and rate of flow in litres per minute is volume divided by time. By recording each activity and counting the uses per day, you can find the total volume of water used and divide by the number of people. Comparing it with the planning figure used by water boards shows how careful your family is.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- A 1 litre bottle or a measuring jug
- A bucket with litre marks
- A stopwatch
- A notebook with a table
- A calculator
- A bar chart sheet
- A family member to help
Safety
For this project: Do the measurements with an adult, and wipe up spills so no one slips. Never measure water from a tank or well alone.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Time how long it takes for the kitchen tap to fill a 1 litre bottle and calculate the flow in litres per minute.
Measure the volume of a bucket bath, a mug rinse, a toilet flush and a washing machine load.
For each activity count how many times your family does it in a day.
Multiply the volume by the number of times and write it in the table.
Add all rows to find the total litres in a day and divide by the number of people.
Record readings on a weekday and on a Sunday to compare.
Draw a pie chart or bar chart to show where most water goes.
Write three changes to save water and estimate the litres saved in a month.
What you should see
Most families find they use between 80 and 150 litres per person per day, with bathing, toilet and washing taking the biggest shares. Your chart shows the activities where saving is easiest.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1What is a litre?
A unit of volume equal to 1,000 millilitres.
2How do you find flow rate?
Divide the volume by the time.
3Which use took the most water?
The answer depends on the family, often bathing or flushing.
4Name one way to save water.
Fix leaking taps or use a bucket and mug instead of a shower.
Take it further
Estimate how many litres a leaking tap wastes in a month by timing the drips into a measuring jug.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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