Capturing wind
Learning Intention:
To understand the workings of wind socks. To understand that testing and recording information is important in an experiment.
Find wind and direction? Thanks to Angle of Attack for the video
Discussion:
Wind is a force that is important for sailing. The sail captures the wind and moves the boat forward. Wind force is also important for flight. Pilots take off into the wind to help push more air over the wing to create lift and land into the wind to provide resistance or drag to slow the plane down. Both sailors and pilots needs to know where the wind is coming from and how strongly it is blowing.
What is a windsock?
A windsock is a type of kite used to detect wind direction. It is a tapered tube of cloth that is held open at one end by a stiff ring.
What does a windsock do in the wind?
Wind is directed down the tube, causing the narrow end to point in the same direction as the wind is blowing. If the wind is strong enough it will float in a horizontal position.
Where have you seen windsocks? Why are they used?
Brightly coloured windsocks are used at airports for pilots to prepare for takeoff or landing. They use windsocks to determine wind direction and speed. Some factories that must regulate the amount of emission they may put into the atmosphere use windsocks to monitor wind conditions - wind speed and direction.
A koinobori is a Japanese windsock meaning carp- streamer fish. It is a symbol for Kodomo no Hi -‘Children’s Day’, which is a national holiday in Japan. The carp is a fish that symbolises courage and the ability to attain high goals. To celebrate Kodomo no Hi families fly koinobori.
The Beaufort Scale is another observational measure of wind speed. It was devised in 1805 and is still used today. The Met Service is New Zealand's national weather authority and it uses many of the terms from the Beaufort Scale when they are describing the wind in their forecasts. https://www.metservice.com
How windy is it today?
The unit of measure for wind speed in New Zealand is kilometers per hour when it is measured over land, but wind over water is
measured in knots or nautical miles per hour.
Activity: Make a Windsock and calibrate it to measure wind strength
Materials:
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Scissors
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Stapler
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Hole punch
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A4 paper
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String
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Felt pens
Procedure:
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Decorate the A4 piece of paper (landscape) with felt pens, drawing all features of a carp/fish - scales, eyes, mouth etc.
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Cut strips of A4 paper, length wise, approximately 2 cm wide.
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Staple the strips along the base of the fish.
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Join the short sides of the A4 paper together with staples.
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Cut another long strip of paper and staple around the head end of the fish. This is just to make it stronger for the string attachments
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Use the hole punch to put a hole on either side of the fish.
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Cut a piece of string approximately 1 metre long.
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Tie each end of each string through the 2 holes
Testing:
Now test your windsock outside!
Take it to an open area to observe the strength of the wind. The wind speed can be gauged by the windsock's angle when held up high. When there is little wind the windsock droops and in high wind it flies horizontally.
How many knots is it today? What angle is your wind sock flying at?
Take your windsock outside on days with different winds and keep a record of the angle that it flies. Make a table that shows what the din strength is when your windsock is at different angles. You might like to use terms such as very light wind, light wind, medium wind, very strong wind, very strong wind.
Glossary:
Wind energy, pungao hau - Electrical energy sourced from harnessing the wind with windmills or wind turbines.
Renewable energy - Energy from something that is not depleted when it is used, like wind or solar power.
Windmill, purere kapo hau - A structure that converts wind power to pump water or mill grain.
Wind turbine, Kopohau - Tall towers with blades that turn in the wind to generate electricity.
Wind farm - A large group of wind turbines for electricity supply.
Lift (in sailing) - An upward force on an aircraft wing or aerofoil. Lift is the result of pressure differences between the top and bottom of an aerofoil.
Drag - The resistance to the movement of a boat through water.
Kinetic energy - The energy of anything moving such as a boat moving or a ball when kicked.
Friction - Is the resistance of motion when an object rubs against another object.
Axle - A rod passing through the centre of a wheel.