How do flying devices and living things counteract gravity?

Targets

At the end of this Unit you should be able to answer the following questions 

2. What forces are involved in flight?

2.1 How do flying devices and living things counteract gravity?

2.2 How does air movement across a surface result in lift?

2.3 How can drag be reduced?

2.4 What means of propulsion are used in aircrafts?

targets

Gravity is the force constantly pulling things towards Earth. To fly, we must overcome the force of gravity and find some way of pushing and moving forward. Various flying devices have various ways of using air to accomplish this.

Think of flying as being like swimming–except, instead of water, flying objects have to move through air. Think of how a swimmer needs to push off the bottom or side of the pool to start floating on the water. Think of how a swimmer needs to move his arms, or legs to push forward in the water. Flying objects need to find ways to "float" on the air and push forward in the air.

Remember that both air and water are fluids; they behave in similar ways!