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Outdoor activity

Backyard Rain Observatory

Transform a simple glass jar into a colourful, scientific weather station to measure how much rain falls from the sky!

Ages 5-12 0-1 hours Education 9/10

Materials

  • Food Colouring optional
  • Glass Jar
  • Markers
  • Ruler

Illustrated Steps

1

Create the Measurement Scale

Use a ruler and permanent marker to draw centimetre lines and numbers up the side of your glass jar.

2

Add the Magic Drop

Place two drops of food colouring in the bottom of the empty jar to dye the incoming rainwater.

3

Secure the Observatory

Place the jar outside in an open area, surrounding the base with pebbles to keep it steady.

4

Record the Storm

Check the water level after the rain, write down your measurements, and empty the jar for next time.

What You’ll Create

You are going to build your very own meteorological instrument—a rain gauge! 🌧️ Using a recycled glass jar, some waterproof markings, and a drop of magical colour, you will create an observatory tool that tells you exactly how heavy the last downpour was.

How to Set It Up

Step 1: Create the Measurement Scale

Take your Glass Jar and hold your Ruler vertically against the outside. Using a permanent Marker, carefully draw a horizontal line at every centimetre mark all the way up the jar. Write the numbers next to the lines so you can easily read them later!

Step 2: Add the Magic Drop

To make the rain easily visible, add exactly two drops of Food Colouring (blue looks amazing!) into the very bottom of the empty jar. When the rain falls in, it will instantly turn into a bright, colourful potion! 🧪

Step 3: Secure the Observatory

Take your jar outside to an open space (away from trees or roofs). Dig a very shallow hole in the soil or arrange some heavy pebbles around the base of the jar so it won’t blow over when the stormy winds arrive.

Step 4: Record the Storm

After a big rainstorm, run outside and check the water level against your marked scale! Write down your findings in a weather logbook, then empty the coloured water and add fresh food colouring drops for the next storm.

Have fun!

  • ⛈️ Make predictions with your family: “I think we’ll get 3cm of rain today!” Who was closest?
  • 🗺️ Create a massive ‘Weather Wall’ chart indoors to graph your rainfall over the entire month.
  • 🌈 Try using red food colouring on Mondays, and blue on Tuesdays—make the rain match your mood!

Why It’s Amazing

  • Meteorology Mastery: Children learn exactly how weather stations track and record precipitation data. 📊
  • Precision and Patience: Measuring accurately and waiting for nature to perform teaches incredible patience. ⏳
  • Data Science: Turning physical water into numbers on a chart is the foundation of data collection.

Pro Tips

For ages 5-8, focus on the ‘magic’ of the water changing colour and learning to count the lines. For ages 8-12, challenge them to calculate the weekly average rainfall and compare it to the local weather forecast online!