Windy Wonders: Build Your Own Weather Vane!

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It’s March, which means the winds are picking up and storms can happen at the drop of a hat. And when the winds pick up, what does that mean? We do experiments with it! Enter, the weather vane!

We quickly covered the cardinal directions my oldest’s kindergarten math, but only to the extent of what North, South, East, and West mean. We didn’t get the chance to practice measuring the cardinal directions.

This week’s experiment, specifically where we figure out north for proper weather vane placement, was a great experience to measure the cardinal directions. We also got to talk about where the wind was coming from, that wind from the north is typically a little cooler than wind from the south, and so much more.

Time to get outside and talk about the weather!

How to make the Windy Wonders Weather Vane STEM experiment

Supplies you will need

For this experiment, you’ll need:

Supplies needed for the Windy Wonders Weather Vane STEM experiment

Before you start

If it is especially windy, consider using some rocks on the paper plate to hold the weather vane in place.

Instructions

Here is how to do this experiment with your child:

Step 1: Cut out shapes for the weather vane

Cut out two rectangles that are equal sizes about 3” long and two triangles that are much smaller.

The rectangles will be used in the back piece of the weather vane to catch the wind, so it needs to be bigger than the triangles.

Step 2: Hot glue the rectangles to one end of the straw

Put a line of hot glue on one of the rectangles and press the straw into the hot glue. Next, add a line of hot glue on top of the straw and press the other rectangle on top, making the ends of each rectangle line up with one another.

A line of hot glue on the first rectangle

Final result of the rectangles glued to the straw

Step 3: Hot glue the arrows to the straw

Repeat the steps you did for the rectangles for the two arrows. If your triangle is not an equilateral triangle, be sure to put the longest side facing the rectangles.

First, add a line of hot glue to the first arrow, then press the straw into the arrow. Next, add a line of hot glue to the straw and press the other arrow into the straw. Ta-da!

Adding a line of hot glue to the straw to add the arrows

Step 4: Draw the cardinal directions on the paper plate

Use your marker to draw N for North, E for East, S for South, and W for West on your paper plate.

Add the cardinal directions to the paper plate with a marker

Step 5: Pierce a hole in the bottom of the paper cup

Use something sharp to poke a small hole in the bottom of the paper cup. The hole should not be bigger than your unsharpened pencil.

Step 6: Stick the paper cup to the paper plate

Add a line of hot glue to the rim of the paper plate and press it into the center of the paper plate, making sure it does not cover any of your cardinal directions you wrote in the previous step.

Add a line of hot glue to the rim of the paper cup

Step 7: Complete the weather vane

Last step! Press the unsharpened pencil into the paper cup with the eraser sticking up.

Use your tack and press it through the middle of the straw and then press the tack into the pencil eraser.

Be sure to not make the tack too snug in the pencil eraser or it will keep your weather vane from freely spinning.

Step 8: Test it outside!

Take your creation outside on a windy day and test out your weather vane!

If it’s too windy, be sure to weigh down the paper plate with some rocks. Ours almost took off in the middle of our experiment!

The STEM behind the Windy Wonders Weather Vane experiment

This experiment teaches:

Weather
Construction
Cardinal directions

How it works

The Windy Wonders Weather Vane experiment demonstrates how a weather vane works, how it can help predict the weather, and the cardinal directions. It’s also a great engineering project for young kids!

A weather vane functions by harnessing the power of wind and the principles of aerodynamics.

Wind, which is simply moving air, exerts pressure on any object it encounters. A weather vane is specifically designed to function on this pressure. It has two main parts: an arrow and a tail, with the tail having a larger surface area than the arrow. This difference in surface area is really important because the larger tail catches more wind, experiencing greater air pressure than the arrow.

The weather vane is balanced on a pivot point, which allows it to rotate freely. When wind blows, the greater pressure on the tail causes it to be pushed away from the wind source. Thanks to the weather vane rotating freely and the fact that the rectangles are a larger surface area, the tail moves away, and the arrow points in the direction from which the wind is coming.

Essentially, the weather vane acts like a simple lever, where the wind’s force on the larger tail causes the vane to rotate until it aligns with the wind’s direction.

Weather

A weather vane’s primary function is to show wind direction, as opposed to an anemometer, which measures the wind speed. The direction the arrow points shows the direction the wind is coming from, so it’s helpful to add in the cardinal directions (north, south, east, west) to the weather vane.

The weather vane is made up of the body that it pivots on and the arrow on top that shows the direction of the wind. The back end of the arrow is thicker and wider and the arrow itself is much smaller. That way, the back end of the arrow gets rotated from the wind until it is no longer pushed against (it’s parallel with the wind flow) and the arrow points to where the wind is flowing from.

So, if the weather vane points to the south, that means the wind is coming from the south.

One of the cool things about the weather vane is that it’s giving you a tangible understanding of an otherwise invisible force!

Figuring out wind direction can also give you some insights into weather patterns. If the wind is coming from the north, that typically means that colder air is coming in.

They can learn how wind is related to other weather phenomena, such as:

Storms: Changes in wind direction can signal approaching storms.
Temperature: Wind can carry warm or cold air masses, affecting local temperatures.
Precipitation: Wind can influence the movement of rain clouds.

Construction

Building the weather vane is a great way to talk to kids about construction and how most things are built with a purpose. In our case, the purpose of building this is to indicate wind direction.

You can talk about the materials used, too, by discussing using cardstock instead of printer paper (cardstock is less flimsy), hot glue instead of a glue stick (adheres faster and better), and ensuring the tack isn’t pushed too far into the pencil’s eraser (to allow the straw to move freely).

They learn that for the weather vane to function properly it must be balanced. They will learn that the “tail” of the vane must be larger than the “arrow” portion, to properly catch the wind.

Cardinal directions

To use our weather vane properly, kids have to understand (or be taught!) the cardinal directions (North, South, East, West). This is really helpful to learn geographical concepts and helps them accurately describe the wind’s direction using the weather vane.

You can even step it up a notch and add degrees around your paper plate to indicate direction so you can measure more precisely.