Lesson Starter Explain why the pencil appears to bend in water?

The pencil appears bent because light travels at different speeds in different materials. This causes the light to bend/refract. Refraction is the change in the direction of light.

Learning Intention To be able to identify the relationship between angle of incidence and angle of refraction

Light can travel through TRANSPARENT objects like glass. Sometimes you can only see a glow of light through something. Materials like this are TRANSLUCENT.

SHADOWS _________ are made because light cannot travel through some objects. Light cannot bend around them either. Things that light cannot travel through are called OPAQUE.

LIGHT Light can travel through objects that are transparent When light enters dense transparent material it slows down Light travels SLOWER through glass than through AIR REFRACTION can cause the direction of light to change when it enters at different angles

Experiment Aim To investigate how the angle at which the light enters the semi circle glass block effects the angle at which it leaves the glass block. How does angle 2 compare to angle 1?

Experiment Draw normal Draw incident angles at 10- 40° Find the relationship between the angle of incidence and angle of refraction 

Investigating Refraction Angle of Incidence Angle of Refraction 10° 20° 30° 40°

Conclusion Refraction doesn't happen if the waves cross the boundary at an angle of 90° (called the normal) - in this case, they carry straight on. The angle of refraction is less than the angle of incidence

Writing your report Aim Apparatus list Method (step by step) Safety instructions Results- stick in your ray diagram and table of angles Conclusion