Paper Cup Anemometer

What You’ll Create

Your own weather instrument! 🌬️ Your little meteorologists will build a real working anemometer (wind-speed measurer) by attaching paper cups to straws that cross through a central pivot. Take it outside and watch the cups catch the wind and spin — count the rotations to measure wind speed just like real weather stations do!

How to Set It Up

Step 1: Prepare the Cups

Take four paper cups and poke a small hole near the rim of each one using scissors or a pencil point. The holes should all be at the same height. Colour one cup with a marker so you can count rotations easily. ⚠️ Adult Helper Needed for poking holes. ✂️

Step 2: Build the Cross

Take two straws and push one through the other at their midpoints to form a plus-sign (+) cross. Secure the intersection with a small piece of tape so they don’t slide apart. This is the spinning arm of your anemometer. ➕

Step 3: Attach the Cups

Push one end of each straw through the hole in a paper cup. Tape the straw to the inside of the cup so it’s secure. All four cups should face the same rotational direction (clockwise or anti-clockwise) — this catches the wind and makes the cross spin. 🥤

Step 4: Add the Pivot and Test

Push a pencil or pen through the centre of the straw cross as a vertical pivot. Stick the pencil into a ball of modelling clay or tape it to a stick to hold it upright outdoors. Hold it up in the wind and watch it spin! Count how many times the coloured cup passes in 30 seconds to measure wind speed. 🌪️

Have fun!

• 📊 Make a wind diary — measure the wind speed at the same time each day for a week!
• 🏃 Run with your anemometer and watch it spin faster — you’re making your own wind!
• 🎨 Decorate the cups in different colours so the spinning creates a colour blur!
• 📻 Check your readings against a real weather forecast — how close were you?

Why It’s Amazing

• Meteorology: Building a real weather instrument teaches how wind speed is measured and why it matters for weather forecasting. 🌤️

• Physics of Motion: Watching cups catch wind and convert it to rotational motion demonstrates force, drag, and energy transfer. ⚡

• Data Collection: Counting spins and recording results over time introduces scientific measurement and data analysis skills. 📊

• Engineering Design: Getting all cups to face the same direction and balancing the cross teaches careful assembly and troubleshooting. 🔧

Pro Tips

For ages 3–5: Adults should build the cross and poke holes. Let kids attach cups with tape, colour the marker cup, and hold the anemometer in the wind. Counting spins together is great maths practice!

For ages 5–8: Let them do most of the assembly with supervision for hole-poking. Create a simple wind scale: 0–5 spins = calm, 5–15 = breezy, 15+ = windy. Record readings in a notebook.

For ages 8–12: Build a proper wind-speed scale by calibrating against known conditions. Add a base that holds the anemometer upright. Research the Beaufort Scale and map your spin counts to it. Compare readings from different locations (open field vs. sheltered garden).

Secret Pro Move: Use a sharp pencil as the pivot and push it through a small bead before inserting through the straw cross — the bead acts as a bearing and lets the anemometer spin much more freely and accurately! 🎯