Teaching your students about the water cycle? Building a DIY rain gauge from a plastic bottle is a fun, hands-on activity to explore a key water cycle process: precipitation. This simple project is perfect for your classroom or homeschool and can be a stand-alone lesson or part of a larger study of water cycle processes.
Before we dive in: The activity from this post comes from my complete Water Cycle Unit. If you’re an educator planning to teach precipitation and the water cycle, you’ll find printable directions, worksheets, and much more in the Water Cycle Unit (plus you’ll support my blog with your purchase! ❤️)
Materials
Gather the following materials to complete this activity:
- 2 empty plastic soda bottles of the same size
- Scissors
- Ruler
- Permanent marker
- Student worksheets & printable directions (available in my Water Cycle Unit!)
Measuring Precipitation: Step-by-Step Directions
The basic idea of this lab is that you will build your own rain gauges out of plastic soda bottles and then use them to collect and measure precipitation in two places. Assist your students as they work through the following steps.
Pre-Lab
In this lab, students will compare the precipitation measured in at least two different locations. For example, they could compare an area with trees and an area out in the open. Or they could give one rain gauge to a friend on the opposite side of town.
Before starting the lab activity, ask your students to make some predictions and explain their reasoning. Which location will receive more precipitation? Or will both locations receive the same amount? Explain your reasoning.
Part 1: Make Your Precipitation Gauge
You will need to build your precipitation gauges and then wait several days to collect your results. First, here’s how to make your own precipitation gauges from plastic bottles:
- Cut the plastic soda bottles in half below the tapered necks (an adult should do this step for younger children).
- Turn the bottlenecks upside down to make funnels.
- Use a ruler and permanent marker to make measurement markings (e.g., centimeters or inches) up the side of the bottle, starting from the bottom.
Part 2: Measure Precipitation
Several days later, complete the experiment:
- Place each precipitation gauge outside. You may wish to stack rocks around the gauges to keep them from tipping over.
- Compare the precipitation in two locations. Try placing one precipitation gauge somewhere with trees and one out in the open. Or give one gauge to a friend or family member who lives nearby.
- In winter, if you have snow, remove the funnel from the top of each gauge bottle to allow snow to fall directly into the base of the bottle. Bring the gauge inside to allow the collected snow to melt to measure snow water equivalent.
Post-Lab
For an extra math challenge: Measure the diameter (D) of the precipitation gauge and then calculate the volume of water that you collected in each rain gauge using the volume of a cylinder equation:
You may also wish to ask your students to reflect on their predictions. Were their predictions correct? Which location received more precipitation? What mechanism might have caused this?
What’s Next?
Once you’ve measured precipitation, why not measure other water cycle processes? Be sure to check out my blog post explaining how to measure stream flow with your students and how to measure evaporation!
Materials for Teaching Precipitation and the Water Cycle
Save time preparing for this activity! My Water Cycle Unit includes printable directions and worksheets for this activity and two other water cycle activities. Plus flashcards, diagrams, and more. Check it out:
Explore more lessons from Wild Earth Lab:
If you enjoyed this post, I know you will love trying my other printable science and nature units in your classroom too!
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