How to Design a Rain Gauge Using a Jar

A rain gauge tells you how many inches of rain have fallen.

Whether for personal curiosity or garden-planning necessity, a rain gauge helps keep track of precipitation. A rain gauge is an instrument used for measuring the amount of liquid precipitation that falls in a given period of time. Amateur weather enthusiasts, gardeners, kid scientists and others can benefit from a deeper understanding of precipitation with a rain gauge. While a variety of commercial rain gauges are available in stores, making one using easy-to-find materials is easy and fun.

Things You'll Need

• Jar with straight sides such as an olive jar
• 2 rubberbands that can fit snuggly around the jar
• Clear, flexible plastic ruler
• Clear waterproof tape
• Fine point permanent marker (optional)

Instructions

Make a rain gauge

1. Wash your jar and completely remove the label. The jar can be plastic or glass of any diameter as long as the sides are straight from bottom to top. Use a jar that is at least 4 inches tall.

2. Secure the ruler to the outside of the jar with the rubber bands. Align the bottom edge of the ruler with the bottom of the jar.

3. Tape the ruler to the outside of the jar with clear waterproof tape. Use a piece of tape in the center of the ruler to hold it in place when you remove the rubber bands. Tape the ruler securely in place, but check that you can read the measurements

   For another option, mark the measurements onto a strip of tape with a permanent marker and adhere that to the jar rather than the ruler.

   If the ruler is longer than the jar and sticks up over the top, cut off the excess.

4. Choose a location for your rain gauge. Find a spot that is away from buildings or trees, which might impact its accuracy.

   Read and empty the gauge after each rain event.

Tips & Warnings

• Use a wire coat hanger to make a holding rack for your rain gauge by untwisting the hanger and then wrapping it around the jar. Leave the hook part of the hanger intact to hang the gauge or nail it onto a wooden post or fence.

• Do not leave rainwater standing in your rain gauge. Standing water is a breeding ground for mosquitoes.

References

• Weather Scope: Make and Use a Rain Gauge to Measure Precipitation
• Weird Science Kids: Make a Rain Gauge
• The Franklin Institute: Make Your Own Rain Gauge

Resources

• Miami Museum of Science: Measure Rainfall