Potential Scienific Questions

• How many muons from space are there around us?
• What is the rate of the Earth's rotation?
• With what angle of attack can a model wing generate maximum lift?

Experimental Idea

A wind tunnel and a model wing can be built using cardboard. Install a fan at one end of the wind tunnel to generate airflow. The model wing needs to be put on a electronic scale in the tunnel. By recording the displayed weight, we can calculate the lift force. Adjust the angle of attack of the model wing and compare the lift force.

Background Research

Airfoil Section

An airfoil is a teardrop-shaped device featuring two curved surfaces. Each of the surfaces has a different curve and camber, which serves to direct the airflow in specific ways around its shape. It is capable of generating significantly more lift than drag.

Angle of Attack

In fluid dynamics, angle of attack (AOA, α) or is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air.

Wind Tunnel

A wind tunnel is "an apparatus for producing a controlled stream of air for conducting aerodynamic experiments". The experiment is conducted in the test section of the wind tunnel and a complete tunnel configuration includes air ducting to and from the test section and a device for keeping the air in motion, such as a fan. Wind tunnel uses include assessing the effects of air on an aircraft in flight or a ground vehicle moving on land, and measuring the effect of wind on buildings and bridges. Wind tunnel test sections range in size from less than a foot across, to over 100 30 m, and with air speeds from a light breeze to hypersonic.

Lift Force

When a fluid flows around an object, the fluid exerts a force on the object. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it is defined to act perpendicular to the flow and therefore can act in any direction.

If the surrounding fluid is air, the force is called an aerodynamic force.

There are many explanations for the generation of lift found in encyclopedias, in basic physics textbooks, and on Web sites. Unfortunately, many of the explanations are misleading and incorrect. Theories on the generation of lift have become a source of great controversy and a topic for heated arguments.