Measure the rain
You will measure rain collected in one open container each day. A wide rim feeding a narrow base can exaggerate the water depth, so container shape matters before the first rain.
- Nature
- Explorer
- About 10 minutes
Grown-up needed: yes for selecting the location, materials and supervising each observation
What you need
- A clear straight-sided plastic container with matching mouth width
- A ruler
- Paper and pencil
- A grown-up
The rule
Empty it at the same time each day.
How to do it
- Ask a grown-up to choose an open level position for the container.
- Place it upright away from roof drips and splashes.
- Return with the grown-up at the agreed daily time in suitable weather.
- Read the collected water depth with the ruler.
- Record the depth in millimetres and the date.
- Empty it at that time before returning it to the same position.
Why it works
Rain depth describes how much water would cover a level area if none ran away. A straight-sided container with the same opening and base width can approximate that depth directly. A wider mouth collecting into a narrow base needs a correction, because it concentrates the water. Roof drips, splash and evaporation can also distort a reading. Keeping shape, position and timing consistent makes a household record more useful without making it a professional weather measurement.
Make it harder
- Record a full week of daily readings.
- Compare your millimetre readings with centimetres.
- Explain why a roof-drip location would bias the collection.
Ask Taz
- Why does the container need straight sides?
- Why do I empty it at the same time?
- Why should it stand away from roof drips?
For grown-ups
A grown-up places and empties the container, and nobody goes outside during a storm to meet a diary time. Record a delayed visit honestly. Keep collected water out of mouths. Ask at dinner: “Which feature of the container or its position could make the rainfall reading look larger than it was?”
Taz is an AI and can be wrong, so stay close by. Read how safety works on Taz.
Show us yours
Film your hands and what you made, not your face or name. Ask a grown-up before posting anywhere else.
Questions parents ask
What if we do not see the expected result?
Record what actually happened, including missing sightings or changes in conditions. An observation does not need to match a hoped-for example. The listed time is an estimate and some activities need repeated visits.
Should we collect something to take home?
Follow the rule for this activity and leave living things undisturbed. A sketch and a few words are usually enough to keep the observation without removing anything from its place.
Must we show the record online?
No. Keep the record at home if you prefer. Any online sharing needs grown-up permission and the privacy line above.
More to try
See all Taz Challenges, or look through the science labs. One place for every why. Ask for early access at aitaz.com
Try it in 3D: Water cycle.