Make an Anemometer

Anemometer is the instrument we use to measure wind speed.

Single hole punch (I used a belt loop punch)
5 small paper cups (PRO TIP: use one paper cup that’s a different color than the others, so it’s easier to pick out when it spins around one full time.)
3 thin wooden dowels
Empty 16 oz water bottle
Scissors
Duct tape

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Use the hole punch to make one hole in the side of four of the paper cups (all roughly in the same place) and four equally-spaced holes around the rim of the fifth. PRO TIP: on that fifth cup, the two holes opposite each other need to be in the same spot. The other set of two holes opposite each other should be slightly lower than the first set.
Slide two wooden dowels through the holes in the center cup to make an “X”.
Add the four other cups to the ends of the dowels, so they’re all facing the same way. Tape them in place.
With the last wooden dowel, Use the scissors to poke a hole in the bottom of the center cup, place the last wooden dowel through it, and tape it to the center of the “X”.

Put the center dowel into the water bottle
To calibrate: ask an adult to get in the car with you. Drive 10 mph (adult: just set the cruise control on a long stretch of road), hold your anemometer out the window and count how many times it spins around in 30 seconds. Do the math! In 30 seconds your anemometer spun Z number of times when the wind was blowing 10 mph. If your anemometer spins 40 times, how many mph is the wind blowing?

What important weather information can an anemometer give us?

Weather-school