Refraction of light

1. Refraction of light Done by: Chia Chu You

2. Objectives • To study: • Revisit the pre-existing knowledge that we have to explain this process • Some interesting facts about refraction. • How does it occurs? (Simplified explanation) • The properties of light • The properties of water • The waves of light that enable this to happen? • What happens during the process?

3. Some basic knowledge (Review) • We all know that human eyes can see things because the light that bounces off the object is reflected into our eyes thus enabling us to see. • We all know when there is no light, we cannot see things in the dark. • I bet that all of us have an experience in the dark, walking without being able to see things. • Wait! There is light in the refraction process, which enables us to see. However, it is not fully clear. The light is distorted. So…What happens when that light is distorted? • We have a distorted image! • Conclusion : Refraction had occurred.

4. The interesting facts • In physics • Deflection of a wave on passing obliquely from one transparent medium into a second medium in which its speed is different, as the passage of a light ray from air into glass. • Other forms of electromagnetic radiation, in addition to light waves, can be refracted, as can sound waves. • Also,a light ray entering a different medium is called the incident ray; after bending, the ray is called the refracted ray.  • Applications of Refraction: • A lens uses refraction to form an image of an object for many different purposes, such as magnification. • A prism uses refraction to form a spectrum of colors from an incident beam of light. • Refraction also plays an important role in the formation of a mirage and other optical illusions.

5. Why refraction occurs? • Refraction occurs when: (A really quick one) • Light enters two substances of different densities. • It bends because the mass of the two substances are different. For example: • The spacing of particles are different. (Blue is water/ Red is Air) • The density is different, which affects the speed of light passing through it.

6. Common occurrence of refraction • Rainbows • The light is first refracted entering the surface of the raindrop, reflected off the back of the drop, and again refracted as it leaves the drop. • The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40–42°. • The angle is independent of the size of the drop, but does depend on its refractive index. • Seawater has a higher refractive index than rain water, so the radius of a "rainbow" in sea spray is smaller than a true rainbow • This is visible to the naked eye by a misalignment of these bows.

7. Technical definitions • The ray of light which strikes the surface is called the incident ray. • The ray of light which leaves the surface is called the reflected ray. • A line perpendicular to the surface is imagined at the point of reflection. • The more detailed explanation on youtube. • http://www.youtube.com/watch?v=Lpldj9cfhYQ

8. Reference • http://education.yahoo.com/reference/encyclopedia/entry/refracti • http://answers.yahoo.com/question/index?qid=1006040900287 • http://en.wikipedia.org/wiki/Refraction • http://zonalandeducation.com/mstm/physics/light/rayOptics/reflection/reflection1.html • http://www.youtube.com/watch?v=Lpldj9cfhYQ

9. Thank you for your kind attention!