Here’s a step-by-step guide to making an anemometer working model using plastic balls, pushpins, straws, and a paper cup stand.
An anemometer is a device used to measure wind speed, and this simple model demonstrates how it works by rotating with airflow.
Materials Needed:
- 4 Plastic balls – lightweight (like ping-pong or small craft balls)
- 2 Straws – for arms of the anemometer
- Pushpin – to act as the pivot point
- Paper cup – to serve as the base/stand
- Pencil with eraser – for mounting the rotating arms (must have an eraser on top)
- Tape or glue – for securing the plastic balls
- Scissors – to cut the straws
Steps to Build the Anemometer Model:
Step 1: Create the Arms with Straws
- Take two straws and cut them to equal lengths (around 15 cm). These will form the cross-arms of the anemometer.
- Cross the two straws to form a plus (+) shape. Use a pushpin to secure them together in the center. Ensure the straws can spin freely when mounted later.
Step 2: Attach the Plastic Balls
- Use tape or glue to attach a plastic ball to one end of each straw. These balls will catch the wind and cause the anemometer to spin.
- Make sure that only one ball faces inward while the other three face outward. This imbalance ensures that the device rotates smoothly in response to airflow.
Step 3: Prepare the Stand
- Insert a pencil (with an eraser) through the bottom of the paper cup. The eraser should sit on top, acting as a soft base to hold the pushpin.
- Secure the pencil in place by taping it to the paper cup.
Step 4: Mount the Cross-Arms on the Stand
- Push the center of the straw arms (where the two straws cross) into the eraser using the pushpin.
- Ensure the pushpin is not too tight – the straws should rotate freely around the pencil when exposed to air movement.
Step 5: Test the Anemometer
- Place the anemometer in front of a fan or take it outdoors on a windy day.
- Observe how the straw arms spin as the plastic balls catch the wind. The faster the wind blows, the faster the anemometer will spin.
How the Model Works:
- The plastic balls act like cups in a real anemometer, catching the wind as it blows.
- The imbalance in weight (with only one ball facing inward) ensures the device spins smoothly.
- The pushpin acts as a pivot, allowing the straws to rotate freely around the pencil.
- As the wind blows faster, the spinning speed increases, showing a higher wind speed.
Summary:
This simple anemometer model demonstrates how wind speed can be measured through rotation. It’s an engaging way to understand how real weather instruments work. With minimal materials, this project is perfect for school science projects!