Weather Vane Project

Hot air balloon pilots do not have a steering wheel or any other mechanical means of steering their balloons. Sometimes, though, the wind at several thousand feet above the ground (winds aloft) will be going a different direction than that which is blowing over the surface. With these changes of direction, the pilot is able to do some "navigation" by controlling to some extent where the balloon will fly and where it will land. Pilots always get a weather and winds forecast before every flight so that they will have an indication of the direction and speed the balloon will travel once launched. Remember though, it's mostly up to Mother Nature!

One way of determining which way the wind is blowing is to build a weather vane.

Materials List
Drinking straws
Straight pins
Pencils with erasers
Feathers about 4 inches in length

1-Put a pin through the middle of a straw.
2- Push the pin down into the pencil eraser. Don't put too much downward pressure on the straw (it has to be free to move)
3-Push the feather into one end of the straw far enough so that it stays.
4-Take your weather vane outside and test it in the wind at different times. Did you notice any changes of direction during different times of day, or during the week? Do you think these changes are related to weather systems?

Extension:
Chart the winds observed outside your window for a week. Use the Beaufort (developed 1806) Wind Scale:

When is it typically the windiest during the day?
What do you think would cause this?
What is the best time of day to fly hot air balloons?
What would be the best speed of wind to fly in? Why?