Aerodynamics are complicated but paper planes are a simple way to start pupils thinking about the subject.

Make a paper aeroplane from an A4 sheet. Fold the paper in half lengthways and open out. Fold in the top two corners to meet at the central fold. Fold both these sections again, so that the folds meet at the middle.

Turn over, and fold one wing to create a fold parallel to and about 2cm away from the centre. Open out and repeat on the other side.

Hold the plane by the central fold and tape the top of the wings together so that they tilt upwards.

There are four main forces to think about when flying a plane - thrust (provided when you throw the plane), drag (resisting the plane’s movement), gravity (pulling the plane downwards), and lift (keeping the plane in the air). See what your students can work out about these forces by trying the following ideas.

l Throw the plane at different angles and with different throws - how does the amount of thrust affect its behaviour? 7

* Attach a paperclip under-neath the plane to stabilise it. How does its position affect the flight?

* Find the plane’s centre of gravity by balancing it on two fingers (at the back and the front) and drawing them together until the plane is balanced on one finger. Work out the best position for the centre of gravity if you want a plane that flies upwards. 7

* Add flaps by making two 1cm cuts on the back of each wing, so the wings are symmetrical. Push the flaps up and see how this affects the flight. As the plane moves, the air pushes against the flaps and the plane moves upwards. What happens when the flaps are pushed downwards or if they are made really big?

* Make a plane with smaller wings. Does this affect lift?

* Try using different weights of paper for your plane.

Have a competition to explore what your students have found out. You could have different prizes for the longest time in the air, the furthest distance travelled, the highest flight, the most acrobatic flight, and for landing on a specific target.