## Refraction and Lenses Module

The Refraction and Lenses module consists of 11 missions (assignments) that address such topics as refraction, the dependency of the direction of bending upon relative light speed, medium density and index of refraction values, Snell's law, total internal reflection, and converging and diverging lenses. The 11 missions and the corresponding objectives are listed below.  Tap a mission's name to begin.

#### Mission Objectives:

Objectives
• The student should be able to identify what refraction is.
• The student should be able to identify the cause of refraction and should understand the sole exception to light changing speed without changing direction.

Mission RL2: Light Speed and Refraction

Objectives
• The student should be able to identify the angle of incidence and the angle of refraction.
• The student should be able to relate the direction which light bends (towards or away from the normal) if given the relative speed of light in the two medium.

Mission RL3: Optical Density, n, and Refraction

Objectives
• The student should be able to relate the index of refraction to the tentative optical density of a material and to the relative speed at which light travels through the material.
• The student should be able to relate the direction which light refracts (either towards or away from the normal) to the relative index of refraction and optical density of the two media.

Mission RL4: Snell's Law

Objectives
• The student should be able to identify the angle of incidence and the angle of refraction.
• The student should be able to use Snell's law to algebraically solve for an unknown quantity (such as the index of refraction or the angle of refraction).

Mission RL5: Total Internal Reflection (TIR)

Objectives
• The student should be able to use an understanding of boundary behavior of light to predict the effect of changing incident angle upon the brightness and relative amount of energy in the reflected and refracted light.
• The student should be able to identify the two prerequisites for the occurrence of total internal reflection and apply these to determine whether or not it could occur in any given situation.

Mission RL6: TIR and Critical Angle

Objectives
• The student should be able to define critical angle and use the concept to determine whether a light ray would undergo total internal reflection in any given situation.
• The student should be able to combine a conceptual and mathematical understanding of critical angle in order to compare critical angles for different boundaries if given a diagram or index of refraction values.

Mission RL7: Converging vs. Diverging Lenses

Objectives
• The student should be able to identify a lens as being converging or diverging (based on its shape) and relate the shape of the lens to the manner in which light rays refract.
• The student should be able to apply the basic rules of refraction to converging and diverging lenses by predicting the manner in which light will refract.

Mission RL8: Converging Lenses - Ray Tracing

Objectives
• The student should be able to identify the correct incident and refracted rays in ray diagram for a converging lens.
• The student should be able to identify correctly drawn ray diagrams for converging lenses.

Mission RL9: Converging Lenses - Image Characteristics

Objectives
• The student should be able to identify the characteristics of images (size, location, orientation, and type) produced by converging lenses for a variety of object locations.
• The student should be able to use an understanding of image characteristics to match a converging lens image with a given object based n the image size, location and orientation.

Mission RL10: Diverging Lenses - Ray Tracing

Objectives
• The student should be able to identify the correct incident and refracted rays in ray diagram for a diverging lens.
• The student should be able to identify correctly drawn ray diagrams for diverging lenses.

Mission RL11: Diverging Lenses - Image Characteristics

Objectives
• The student should be able to identify the characteristics of images (size, location, orientation, and type) produced by diverging lenses for a variety of object locations.
• The student should be able to use an understanding of image characteristics to match a diverging lens image with a given object based n the image size, location and orientation.