TAMPA, Fla. — A weather vane is an instrument used to show the direction the wind is blowing from. It is one of the simplest weather instruments created and it has been used since ancient times.
The weather vane is made up of a tail and arrow. The tail fin catches the wind and the arrow points toward the direction the wind is blowing FROM.
If the arrow on the weather vane is pointing north then it means there is a north wind. In other words, the wind is blowing from north to south.
Knowing the direction the wind is blowing from can be very useful for a variety of reasons especially for farmers, pilots and meteorologists.
Meteorologists use wind direction to get a sense of what kind of weather is coming. Generally speaking, cold air is located to the north and warmer air is located further south.
If the weather vane shows wind blowing from the north, one can say colder air is moving in. This is especially true if the wind direction recently changed to the north, usually a sign that a cold front just passed by.
Pilots use another tool that works much like a weather vane called a wind sock. It tells pilots what direction the wind is blowing from so they know which runway to use for a safe flight.
Weather vanes are often accompanied by another weather instrument called an anemometer. An anemometer measures the wind speed. It uses tiny cups that spin in a circle and the faster the cups spin, the strong the wind.
Weather vanes are widely used as decorative pieces too. A safe bet to find one is on the roof of an older farm building.
Let’s get started and make our own weather vane! If you live on the coast, you can use the weather vane to see if the wind is blowing toward or away from the coast. You can use the knowledge to see if the sea breeze moved through!
Experiment: Creating a Weather Vane
Purpose: Build a weather instrument that can tell us the wind direction
What you need:
- 2 paper plates
- 1 poster board or thick construction paper
- 1 plastic straw
- Scissors
- Modeling clay
- Glue or tape
- Compass
- Markers or colored pencils
- Ruler
- Straight Pin
- Pencil with new eraser
Procedure:
1. Cut two slits at the end of the plastic straw. This will be used to place the tail fin and arrow in later.
2. Draw out the tail fin and arrow on the poster paper. Use the ruler to make straight lines. The arrow will be in the shape of a triangle and the tail fin will look similar. Refer to the video for more details.
3. Stick the arrowhead and tail fin into the slits located on each end of the straw.
4. With an adult, take the straight pin and puncture it through the center of the straw.
5. Stick the pin into the top of the pencils eraser. Make sure there is enough room between the eraser, straw and the top of the pin so the weather vane spins freely. Make adjustments as necessary.
6. Grab a paper plate and place it upside down. Use the ruler to measure where the center of the plate is located and mark it.
7. Use the ruler to draw perpendicular lines intersecting in the center. This will be used for wind directions (north, south, east, west).
8. Decorate the paper plate as you wish.
9. Take the pencil and puncture a hole in the center of the plate.
10. Use the second paper plate and lay it in front of you with the proper side up.
11. Take a handful of modeling clay and place it on top of the plate. This is going to be your weight to hold the weather vane up.
12. Stick the pencil through the modeling clay
13. Push the decorated plate down and you can use glue or tape to stick the two plates together.
14. The weather vane should be able to stand freely at this point.
15. Place the weather vane outside and use the compass to match the north side of the paper plate with magnetic north.
16. Observe findings. If the wind arrow is pointing east then the wind is coming FROM the east.
Results: A functioning weather vane that can be used to tell the direction in which the wind is blowing from.
Conclusion: The weather vane is one of the oldest instruments ever created dating back to the beginning of man-kind. The simple technology is used to tell what direction the wind is blowing from. A sudden change in wind direction might be a sign that a cold front or sea breeze boundary moved through.