A rain gauge is a simple weather tool that measures how much rain falls in one place. Building one from a 2-liter bottle helps students see precipitation as something they can collect, measure, and compare. This project connects weather, measurement, and data recording in a hands-on way.
Over two weeks, a daily rainfall log can show patterns in wet and dry days.
Key Facts
- Rainfall is usually measured as a depth, such as centimeters or inches of water.
- 1 cm of rain means water would cover the ground 1 cm deep if it did not run off, soak in, or evaporate.
- Total rainfall = day 1 rainfall + day 2 rainfall + day 3 rainfall + ...
- A straight ruler scale helps you read the water height in the bottle.
- Place the rain gauge in an open area away from roofs, trees, and sprinklers.
- Empty the gauge after each daily reading so the next measurement starts at 0.
Vocabulary
- Rain gauge
- A rain gauge is a tool used to collect and measure the amount of rain that falls.
- Precipitation
- Precipitation is water that falls from clouds, including rain, snow, sleet, or hail.
- Measurement line
- A measurement line is a mark on the gauge that shows a specific height of water.
- Data log
- A data log is a chart or table where observations and measurements are recorded.
- Evaporation
- Evaporation is the process where liquid water changes into water vapor in the air.
Common Mistakes to Avoid
- Placing the gauge under a tree or roof, because dripping leaves or roof runoff can add extra water and make the reading too high.
- Starting the scale above the bottom water level, because the first measurement mark should match the true zero level where water begins to collect.
- Forgetting to empty the gauge after reading it, because leftover water will mix with the next day’s rain and make the next measurement wrong.
- Reading the water level from above or below, because your eye should be level with the water surface to avoid a measurement error.
Practice Questions
- 1 A rain gauge shows 1.2 cm of rain on Monday, 0.8 cm on Tuesday, and 2.0 cm on Wednesday. What is the total rainfall for the three days?
- 2 Your class records 0.5 cm, 0 cm, 1.5 cm, 0.7 cm, and 0.3 cm of rain during one school week. What is the total rainfall, and what is the average rainfall per day?
- 3 Two students place rain gauges in the same yard. One gauge is in an open space, and the other is under a large tree. Which gauge is more likely to give a fair rainfall reading, and why?