How planes and birds fly in the sky.
People have always wanted to fly like birds and bugs for a long time, but we can't fly through the sky. Read on and you'll find out why us humans can not fly.
Lift is what makes planes and birds go up through the sky and it helps them to take off into the sky. Thrust is what makes planes and birds go down the runway and make the plane move forward in the air. Drag is what helps the plane to stop, slow down and land. Weight is what helps planes and birds return to the ground.
Planes, birds and bugs fly because they are really light. This is why birds need less thrust to fly. An object needs an unbalanced force acted on it to change speed or direction. For example the thrust on a plane going down the runway needs to be stronger than the drag to go forward.
The greater the mass of an object the greater the amount of force needed to move it. This means birds need less thrust and lift to get off the ground compared to planes which need more thrust and lift to get off the ground.
The way that planes get off the ground is because of the speed of planes when they take off - they go around 110-140kms per hour. Birds turn in the sky because they flap and turn their wings really fast through the sky. Planes land on a runway when they bring their tyres out, then put the flaps up so it catches, creating drag, catching the wind which slows it down on the runway.
For years people have wanted to fly through the sky but no matter what we do we can't fly. Hopefully you can see why we can't fly.