Ever wonder how meteorologists tell the weather? They have amazing tools in their toolbox to make understanding weather easy! They pull together information from lots of sources, from satellite images to radar to something as simple as wind speed testing devices. In today’s project, you’ll build a paper cup anemometer, a device that measures wind speed.
What is an Anemometer? And What Does an Anemometer Measure?
An anemometer is a device that measures wind speed. The stronger the wind, the faster the device spins. Meteorologists use anemometers to predict weather patterns. Anemometers are also used to measure gas flow through ducts and vents in heating and air conditioning units.
An anemometer can be calibrated by measuring the number of rotations in a given time and comparing it to the actual wind speed. The wind speed in miles per hour is calculated by measuring the circumference of the anemometer and relating that to the number of rotations per minute.
Why Does the Wind Blow?
Wind is all around us, but what is it and how is wind created? Wind is the horizontal movement of air flowing from areas of higher pressure to lower pressure. The greater the difference in pressure, the higher the wind speed.
So what causes these pressure differentials? It’s all about temperature. The sun heats up the earth, which heats up the air over it. The hotter air is less dense and begins to rise, leaving a low-pressure void over the earth. But the temperature doesn’t rise as high over areas like oceans that can absorb more of the sun’s heat. Cold air over areas like oceans will fall and create the opposite situation, i.e. high atmospheric pressure over the oceans. Wind flows from high pressure over the ocean to the lower pressure areas over land. A similar process occurs on a larger scale with temperature differentials between the earth’s poles and the equator.
Paper Cup Anemometer Supplies
We love this project because it uses some simple tools you probably have kicking around the house or classroom. I used condiment cups because I had those lying around (love them for projects!) but you can also use small bathroom-sized cups as well. Small cups work better than large paper cups in my opinion.
- 4 small paper cups
- Hole punch
- 2 paper straws
- Bamboo skewer
- Rubber bands
- Pony beads
- Room fan (optional)
How to Make an Anemometer with Paper Cups
- Punch a hole in one side of the cup as far away from the top edge as your hole punch will allow.
- Make a second hole directly opposite from the first hole in the paper cup.
- Repeat with three more cups
- Feed a paper straw through the holes in one of the paper cups. Then add a second paper cup on the other side of the straw.
- Repeat with a second paper straw and two more cups.
- Squeeze the center of the paper straw between the two paper cups to flatten it. Punch a hole in the straw with the hole punch.
- Repeat with the other paper straw.
- Wrap a rubber band around a bamboo skewer approximately 2 1/2” from the end. Top the rubber band with a pony bead, both paper cup straws, and another pony bead. Wrap another rubber band at the end of the bamboo skewer to secure.
- Insert the empty end of the bamboo skewer into a cup of playdough to make it stand up.
- Arrange the paper cups so that the cup is parallel to the table and the open ends are all facing the same direction.
- Blow into the cups and watch it spin. If it is having trouble spinning, adjust the placement of the rubber bands to give the straws more room.
How to Test Wind Speed with an Anemometer
- First, test the anemometer by blowing into one of the cups gently. Now blow hard into one of the cups. Did it spin faster or slower?
- Now try using a room fan to test the anemometer. Set the fan to the slowest setting. Place the anemometer in front of the fan and start the stopwatch. Count the number of rotations the anemometer makes in 30 seconds. Record this number.
- Repeat the fan test at medium speed and high-speed fan settings. How did the number of rotations compare from setting to setting? This number is how must faster the comparable wind speed of each setting.
More Weather Activities for Kids
This anemometer is a sneak peek into our Weather STEAM Explorers ebook! Kids will love creating weather in a jar, capturing the daily forecast in an art journal, and becoming a meteorologist with DIY tools. You’ll love the helpful standards-based learning, printables, and tools that make STEAM exploration easy!