Science Outside The Classroom: Making a rain gauge

Published: Apr. 30, 2020 at 10:49 AM CDT
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Did you know that, on average, May and June are two of the top three wettest months on average for the Brazos Valley? You can thank an active weather pattern that sets up over the Lone Star State each spring. This means it is one of the best times of the year to catch up on some much needed rainfall. In today’s experiment, we’re going to show you how you can measure the rain that falls in your backyard and keep track of it at home.

For this activity you will need

• a plastic bottle (can be a 2 liter soda bottle or a regular water bottle) or a glass jar

• masking tape and/or packaging tape

• knife and/or scissors

• permanent marker

• glue

• and a ruler.

How much rain you receive may not be the same as your next door neighbor, your grandparent’s house down the street or even in the next town over. Rainfall is not evenly distributed over an area, so measurements can vary quite a bit over a short amount of space. For this reason, it’s important to record measurements as that data is crucial to knowing if we’re getting out of a drought or inching closer to flood stage. Happy measuring!

Step 1:

Cut off the top of the plastic bottle.

Step 2:

Flip the top over and glue it to the inside of the bottle. You can add packaging tape to make the seal more secure.

Step 3:

Unroll the masking tape and set it next to your ruler. Create markings as precise as you would like on the tape as this will be your measurement standard for your rain gauge. I recommend making markings every quarter of an inch at least. This is especially helpful for glass jar rain gauges and works on plastic bottles as well. If the plastic bottle has too many ridges on it, it may be easier to just draw the markings on the bottle instead.

Step 4:

Secure the bottle or jar to a sturdy object away from a building. These are lightweight and would easily fly around with any higher wind gust. If you don’t have something to fasten it to, I recommend digging a hole in the ground or find a planting pot and bury it in the dirt leaving the top portion visible to collect the rain.

Step 5:

Check your rain gauge and record your measurements. Keep track of them in a notebook by writing down the day and how much rain fell.

Step 6:

Empty the rain gauge. This is easy if you have an open top without a funnel. The funnel will not allow you to empty all the water out of the gauge. In this case, especially if it is a multiple day rain event record the measurements each day and empty after the rain has cleared out (you can use some simple math to then calculate from there your daily totals). With this method, you’ll have to wait until the water evaporates out of the bottom of the bottle -- with the Texas sunshine and heat, that shouldn’t take too long.

Watch the video above for more information on this activity.