Learning Objectives To observe and explain the phenomenon of refraction

How Does a Two-Way Mirror work?

Chapter 12 The Refraction of Light 12.1 What is Refraction?

Try This…. Light through water and glass Penny in bowl with stir stick

Refraction Refraction is the bending or change in direction of light when it travels from one medium to another.

Refraction: Why is the straw bent? Khan Academy: Refraction

What Causes Refraction? Analogy: A car rolling from pavement onto sand.

Refraction is caused by the wave front of light striking the surface of a new medium at an angle other than 90o. This causes one part of the wave to change speed before the other part of the wave.

The Speed of Light In a vacuum: 3.00 x 108 m/s (300,000 km/s) In water: 2.26 x 108 m/s (226,000 km/s) In acrylic: 1.76 x 108 m/s (176,000 km/s)

The Rules of Refraction Angle of Refraction: The angle between the refracted ray and the normal. Light bends towards the normal when its speed decreases in a material. Light bends away from the normal when the speed increases in a material.

Partial Reflection and Refraction Refraction is often accompanied by reflection – called partial reflection and refraction. Eg. Light striking water or a window Few other materials have this dual property Two-way mirrors and mirrored sunglasses reflect much of the incident light.

ROY G BIV says: p. 519 # 1-5 Read p. 515 – 519 Lab Activity: Path of Light from Air to Acrylic You need a calculator for the rest of this unit!

How Does a Two-Way Mirror work?