Rain Gauge


Several cities across the U.S. are experiencing their wettest year-to-date. The National Weather Service is asking for your help in measuring and reporting the amount of rainfall in your city. Using the provided material, build a rain gauge to measure the amount of liquid precipitation over a set period of time.


  • 2 AA batteries
  • 1 Battery holder
  • 5-6 LED lights
  • Electrical Tape
  • 2 Alligator clips with wires
  • 2 Aluminum foil sheets
  • 3-4 Paperclips
  • Hot glue gun & stick
  • 2-3 12-oz. Plastic cups
  • 4-5 Binder clips
  • 2-3 Thumb tacks
  • 1 Ruler
  • 1 Black Sharpie


What is a rain gauge? How does it work? How is a rain gauge used by meteorologists (or weather forecasters) and hydrologists (or scientists that research the earth’s underground and surface water)? Here are a few videos to get you started and don’t forget to take notes:

Where have you seen a rain gauge?


What is unique and rather cool about your rain gauge is that it will light up. So let’s take a look at what is known as a simple circuit. Describe what you notice.


Using some of the materials in the kit, including the battery pack and LED lights, can you create a simple circuit? Can you find more than one way to do this—using different materials in the kit? What materials might be around your home that you can use as conductive material for a simple circuit? Test it out. Also, the legs of the LED lights are different. Which one is positive and which one is negative? How do you know?


Discuss the measurement you will use to measure the rain fall. Millimeters? Centimeters? Inches? Take a plastic cup. Use the ruler to measure the vertical distance or the amount rain fall. Use the sharpie to mark this distance and add your units (e.g., cm, mm, inches) just like you saw in the videos. We will call this your vertical ruler.


Using a thumb tack, poke a hole into your cup—one hole at each mark along your vertical ruler. Insert the longest leg (i.e., positive) of a LED light into each hole. Leave the other leg (i.e., negative) on the outside of the cup. Use hot glue to secure the LED lights and fill the holes. Watch this time lapse video for support:


Take an aluminum foil sheet and wrap around the legs of the LED lights on the outside of the cup. Why are we using aluminum foil?


Straighten one paper clip and insert into the bottom of the cup. Part of the paper clip should be inside the cup, while the other part should be outside the cup. You will use the thumb tack and the hot glue as you did when you inserted the LED lights into the cup.


Look closely at the image, particularly the alligator clips. What do you notice? Which connection is positive and which connection is negative? How do you know? Think back to your research.


Now it’s time to complete your circuit by pouring tap water into the cup. (Psst. Did you know pure water is a very poor conductor? But tap water, like rain water, contains charged ions that allow electricity to flow through.)


Engineers often build and improve upon their prototypes before launching a final product. If it did not work properly, troubleshoot by walking through your steps again and thinking out loud with other family members. How will you redesign the prototype? What improvements might you make to the rain gauge? Explain your thinking.


  1. Using items around your home, plan and build something to cover the battery pack. This cover should uphold the elements of weather. Why is it important to cover the battery pack of the rain gauge from the elements of weather?
  2. What might you add to the rain gauge to make sure that it does not blow over or blow away once set outside? Do some research, make a plan, and add on to your rain gauge.


Now that you have an idea of how to create a rain gauge using the material from the kit, we challenge you to re-create another rain gauge. Keep in mind the process —plan, create, test, and improve. We challenge you to think outside the “kit” and use material in your home.


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