Aeroplanes

Aeroplanes Activity / Energy & Forces

 * Class:** suitable for first class and older

From [|www.primaryscience.ie]

__Science background:__

The space around us is not empty but is filled with air, which pushes on everything around us, which is called air pressure. Moving air has lower pressure than still air, and the faster the air is moving, the lower its pressure. This is known as Bernoulli's Principle, after the Swiss scientist who discoverd this in 1738. This principle is the basis for how airplanes stay up in the sky! Air flows faster over the curved top of the wings than under the flatter bottom.

The slower air underneath has greater pressure which pushes upwards on the plane, and stops it being pulled down by gravity. *The force pushing up, is greater than the force pushing down*


 * Skills:** Predicting, experimenting, measuring and observing.

Get children to first predict what they think is going to happen. After they have carried out the experiment ask them to compare the results with their predicition.

Step 1. Take some thin paper, such as printer or copybook paper, if it is A4 size, cut it in half width ways

Step 2. Hold a thin piece of paper under your chin, and blow over the top of it. What happens?
 * The paper will rise up*

Step 3: Next, hold a piece of paper against each cheek, and blow between them. What happens?
 * The papers move towards each other*

Step 4: Place two books about 10cm apart on a table and lay a sheet of paper across them. Try to get the paper to float away by blowing underneath it.
 * Paper will probably droop in the middle*

Step 5: Place a light plastic counter about 1cm from the edge of the table, and a saucer a little beyond it. Using what was learned in the first activities, try to get the counter into the saucer without touching it.
 * Blow hard across the top of the counter, keeping your mouth level with the counter*

Step 6: Take two polystyrene beakers, putting one loosely inside the other. Hold them close to your mouth and blow across the top. What happens?
 * The top beaker jjumps out because the moving air over the beaker has lower pressure than the still air in the bottom of the beaker, so the top beaker is pushed up and out.

Trigger questions to use:

1. What happens to something when you let it go out of your hand? 2. Why do most things fall (gravity) 3. Why do some things (like a helium balloon) float upwards? (Helium is lighter than air). 4. Do only light things stay up in the air? (No, heavy airplanes can). 5. What would happen to a plane if its engines failed? (It would crash) 6. Does it need to keep moving in order to stay up? (yes) 7. But a helicopter can stay still - how is that? (The rotar blades on top keep moving)

Have you tried this experiment in your classroom? Was it easy to do? Where there any issues? What was your experience? Click on the the discussion tab above to sthare your experiences.

See [] for full worksheet.

Watch an exmaple of an experiment on forces in this YouTube video: media type="youtube" key="zg0wD-ETg-E?fs=1" height="385" width="480"