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WHICH WAY WIND

Learning Intention:

 

To understand and use familiar words about wind direction.  To make and understand how a wind vane works. 

Secrets of the Hauraki Gulf. Thanks to NIWA for the video

Discussion:

 

You can often feel the wind blowing, but can you tell what direction the wind is coming from?

 

Go outside to look for indicators that tell you what direction the wind is coming from.  For example, flags, trees, clouds, blowing paper and  grass blowing. Can you determine the wind direction from what you have observed?

 

There are four basic directions, north, south, east and west.  Where does the sun rise?  Point in that direction. The sun rises in the east.  Confirm with a compass each direction. 

 

The wind is named by the direction it is coming from.  For example, a northerly wind blows from the north to the south.

 

Do you know what a wind vane or weather vane is? 

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It is one of the oldest tools for measuring the direction of the wind, as it points in the direction the wind blows.  Nowadays they are mostly used for decoration, as high-tech weather systems can record all the data that is needed.  Although a wind sock is a type of wind vane that is still used by pilots who like to actually see the wind direction. 

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Have you ever seen a wind vane?  Where was it located?  What did it look like? 

 

Wind vanes are usually found up high, and they are sometimes shaped like a rooster.  You may see them on the tops of buildings, such as schools, barns,  churches, weather stations and on boats.

 

Sailboats often have wind vanes called wind indicators on top of their masts. Why do sailors need to know the wind direction? 

 

Wind plays a role in determining how sailors are going to navigate their course.

 

How do wind vanes measure wind direction? 

 

They work when an indicator, such as a small arrow, reacts to wind gusts and spins on a rod to point in the direction of oncoming wind. The other end of the arrow is wide so it catches the wind.  The wind moves the arrow until it catches both sides of the wide end equally.  The arrow always points into the wind, so you can identify the direction from which the wind is blowing.

 

Winds are caused by variation in air pressure and temperature.  Local winds can change in minutes or hours.  For example, sea breezes and land breezes near the ocean change about every 12 hours.

In most regions, the wind usually comes from one primary direction, called the prevailing wind. 

 

Do you know the prevailing wind in your local area? 

 

Prevailing winds are often influenced by global winds.  Global winds move over the entire planet and do not vary much.  How do you think Polynesians and the first Europeans used their knowledge of prevailing winds to navigate their way to Aotearoa New Zealand?

Activity:  Design, make and test a wind vane then record wind directions.

 

Materials:

  • Scissors

  • Marker

  • Paper cup and plate

  • Drawing pin or nail

  • Paper straw or similar

  • Wooden skewer

  • Card or heavy paper

  • Heavy or corrugated cardboard from a box

  • Hot glue gun or masking tape or sellotape

  • Compass (there is a compass on iPads plus compass phone apps are available if you don't have an actual compass)

 

Procedure:

Work in pairs or groups of three or four.

  1. Write the four directions (N, S, E, W) near the edge of a paper plate.  If it helps draw it on the whiteboard. (You could mark NE NW SE SW as well).

  2. Poke a hole with a drawing pin or nail, in the bottom of the cup.

  3. Slit the hole with scissors just big enough to poke the straw through.

  4. Tip the cup upside down on the table and poke straw through until it touches the table.

  5. Hot glue or tape the straw at the button (now top) of the cup so it sits upright.

  6. Hot glue or tape paper cup, upside down to the inside of the plate.  Set aside.

  7. Cut a strip of corrugated cardboard approximately 24 cm by 1.5 cm.

  8. Cut a square from card approximately 7cm squared.  Cut a small triangle approximately quarter the size of the square.

  9. Glue or tape the square and triangle to each end of the corrugated strip to form the arrow.

  10. Place the pointy end of the skewer through the middle corrugated part of the arrow at the centre and move the arrow to the blunt end of the skewer.

  11. Thread the skewer into the straw on the cup.

  12. The skewer and arrow should be able to move freely in the wind.

  13. You might like to make a design to sit on top of the skewer or decorate the arrow.

 

Testing:

Use your wind vanes and compass to record wind direction.

Take the wind vanes outside and hold them high in open areas, such as a playground area, on a slide, or on the field. Have groups use a compass to find north and align the wind vane N label with real north.

 

Record the wind direction.  Remember that if the vane points to N, then the wind is blowing from the north (not from the south to the north).

 

It is possible to work out what is the prevailing wind in a location by monitoring the wind over time and determining what direction the wind comes from most often.

 

For the next two weeks, monitor the wind direction.  Predict the outcome.  Why do you think that?  Record your results in a table and at the end of the two weeks conclude the direction from which the prevailing wind is coming.  Was your prediction correct?

   

Create a Wind Rose:

A Wind Rose Diagram is a tool which graphically displays wind speed and wind direction at a particular location over a period of time.

 

Create your own Wind Rose Diagram with your collected data, using the wind rose template. For each time the wind blew in a particular direction, colour in a bar on that side of the circle.  Wind rose graphs are used by researchers and meteorologists to show at a glance the prevailing wind direction and when done your wind rose should show you your prevailing wind at a glance.

Glossary:

 

Wind, Kōkōhau - Moving air

 

Ocean, Moana

 

Sailboat, Waka Hourua

 

Tāwhirimātea - The Atua or god of weather including the god of wind.  He is the son of Papatūānuku (earth mother) and Ranginui (sky father)

 

Meteorologist - A weather scientist

 

Oceanographer - Someone who studies the ocean

 

Anemometer - An instrument for measuring wind speed

 

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Wind Vane - A device that measures the direction of the wind

 

Weather Prediction - What you think will happen with the weather

 

Sea buoy - A floating marker in the sea

 

Knot - One nautical mile per hour

 

Compass - A tool for finding direction such as North, South, East or West

 

Sea Breeze and Land Breeze - The winds created by a difference in temperature between the sea and the land

 

Prevailing Wind - The most common wind in a location

Sea State - The height of the waves

 

Wind Rose Diagram - A diagram that summarizes information about the wind at a particular place and over a period of time

 

Ocean swell, Hone - A long rolling wave that is formed a long way away

 

Wind Turbine, Kapohau - A propeller that gets spun by the wind to turn wind power into energy

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