What is your tap water temperature?
- Can you use dissolving sugar to measure tap water temperature?
- Why is tap water the temperature it is?
- Why do people’s results disagree? (Clue: control variables)
Estimated time: 30 minutes, no experience needed
Equipment required
- Kitchen scales
- Water taps
- White granulated sugar
- 2 teaspoons
- Drinking glass
- Jug of water
- Timer (use the one on the video)
- Thermometer (optional
- Paper and pencil
Risks
- Hot tap water can scald handle with care
Steps
Watch the video
- Let the jug of water stand in room temperature for about an hour
- Measure some white granulated sugar at point scale reading just changes from 4 g to 5 g onto a teaspoon
- Pour 200 g of water from the jug into a glass
- If you have a thermometer, measure and note down the water temperature. If you don’t, you can still proceed
- Start the timer when you add the sugar to the water
- Stir with the spoon in time with the video ticking (100 stirs per minute)
- When all the sugar has dissolved, record the time on the timer
- Repeat using the hottest tap water possible take care not to scald yourself
- Repeat using water from a cold tap that’s been running for at least a minute, so it’s as cold as it will get
- Enter the results in the form below on this page
Thoughts, tips and information
SI measurement units
- kilogram (kg) for mass
- kelvin (K) for temperature
- second (s) for timing
Challenge Topics
Measurement Science, Maths, Health
- Which factors (control variables) cause people to get different results? (glass size, sugar amount and type, stirring speed and spoon shape…)
- Hot water is heated to >60 °C to kill bacteria in the boiler. Water >42 °C may scald you.
