Make an anemometer : Fizzics Education

### Welcome!

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# Make an anemometer

### You will need:

• 4 plastic cups (we used 30mL biodegradable cups)
• A sharp pencil
• Two cardboard strips (at least 20 x 3cm each)
• Stapler
• A boxcutter & adult help
• Thumbtack (optional)

1

Form the two cardboard strips into a cross. Use at least two staples to join them together.

Optional: You can use the thumbtack to make a small hole through the middle of the cardboard strips.

2

Use the stapler to attach a plastic cup on the end of each strip of cardboard.

3

Make sure that the plastic cups are all facing the same way.

4

Push the pencil into the centre of the cardboard cross.

5

Take the anemometer out into a breeze and see if it spins!

Extra tip: Colour one of the cups so that you can count it every time it passes in front of you.

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### Online courses for teachers & parents

– Help students learn how science really works

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#### Get the Unit of Work on Pressure here!

• Want to dive into air pressure?
• It’s all about air pressure in many ways!

From how storms form to how planes fly, this unit covers many concepts about air pressure.

Includes cross-curricular teaching ideas, student quizzes, a sample marking rubric, scope & sequences & more

### What is going on?

The stronger the wind, the faster your anemometer moves!

### Design

In this design, the friction between the pencil and the cardboard strips does cause the anemometer to not spin as fast as it could. Can you design a better version? Share your ideas below!

### Variables to investigate

More on variables here

• Can you reduce the friction between the pencil and the cardboard?
• What happens if you increase the cup size?

### Measure the wind speed

1. Measure the length of one cardboard arm that holds a cup.
This is the radius of the circle that the cups travel around.
2. Â Work out the circle circumference of the travelling cups by using the formula below:Circumference = 2 x Pi x radiusÂ  (where Pi = 3.14 as an approximation)
3. Count the number of revolutions in one minute (rpm)
4. Substitute your answers into the formula below to work out Â the wind speed of your anemometer:Wind speed (km/hr) =Â  (rpm x circumference x 60 minutes) / 1000 meters

#### Worked example

Eg: Â Â Â  If an anemometer spins 90 times in 1 minute,Â and it has a measuredÂ  circumference of 1 metre…

Wind speed (km/hr)Â  = 90 rpmÂ  xÂ  1 meterÂ  xÂ  60 minutes / 1000 metres

= 5.4 km per hour

#### How can you measure wind speed without an anemometer?

The Beaufort scale is a way that you can roughly work out the wind speed based on what you can see happening in the environment around you.