Reflection and Refraction

1. Reflection and Refraction

2. Every second of every day our eyes detect and interpret rays of light – whether that light is coming from a natural source like the sun, or an artificial source like a lamp. One of the properties of light is that it travels in a straight line, unless it is acted on by some external force or condition.

3. However, sometimes our eyes can be fooled by the reflection and refraction of light. When interfered with, the path of light rays can be bounced or appear to be bent away from the original object making it seem larger or smaller than it really is.

4. Reflection When light strikes a surface and is redirected back to its point of origin, this is reflection. We can see objects when they reflect light, and the reflected light enters our eyes. Most objects reflect some of the light that hits them. Smooth, shiny surfaces that absorb very little light, will reflect light at almost the same angle that the light hits it.

5. Mirrors reflect images of objects because light rays bounce off an object, travel in a straight line to a mirror, bounce off the mirror, and then travel to the eye of the observer. Light beams Mirror

6. Refraction • When the path of the light rays change directions and appear to bend we call it refraction. • occurs when light passes from one substance to another of a different density(for example, from air to water) • amount of refraction depends on the angle the light enters the new substance and the difference in the densities of the two • the greater the angle, the more the light ray will be bent

7. Refracting telescopes and regular camerasuselenses to gather and focus light. • Reflecting telescopes gather and focus light with mirrors. In a reflecting telescope, the observer sits inside the telescope, at the focal point of the reflected light.

8. Decide whether each object below best represents reflection or refraction. reflection refraction reflection refraction reflection refraction reflection refraction reflection refraction reflection refraction

9. One way solid objects are classified is by how much light is allowed to pass through that object. • A transparent object lets all of the light pass through. • A translucent object lets some light pass through. • An opaque object lets noneof the light pass through. opaque transparent translucent

10. Now, try answering these questions:

11. Unless acted upon, how does light travel? • Bent at a 500 angle. • In a straight line. • In a curved arch. • Light doesn’t have a preferred path.

12. Answer B is correct: • Light travels in a straight line.

13. These answers are not correct because – • Answer A – Although light is often bent at a 500 angle, that only happens when something acts upon it to make it change its path. • Answer C – Light does not usually travel in an arch. • Answer D – Light does have a preferred path – a straight line.

14. All the following are examples of light being refractedEXCEPT — C A B D

15. Answer choice D is correct. The mirror is using reflection to bounce light off of its surface.

16. These answers are not correct because: • Answer A – Look at the bent light rays. A rainbow is the result of light being refracted. • Answer B – Look at the bent light rays. A prism bends light. • Answer C - The straw looks bent in this picture. It is an example of refraction, not reflection.

17. In this picture, the straw appears to be bent. This is because – • milk is an opaque substance. • light is being refracted. • it is a magic trick. • light is being reflected.

18. Answer B is correct. • The straw appears to be bent because light is being refracted as it passes through the air into the liquid.

19. These answers are not correct because: • An opaque substance – if the liquid were opaque, we would not be able to see the straw. • A magic trick – it is not a trick that the light is being bent, or refracted, as it moved through the liquid • Light being reflected – although some light may be reflected by the glass, that is not the reason why the straw appears to be bent.

20. Which of these objects best illustrates reflection? • Prism B. Rose Quartz • C. Window D. Paper

21. Answer C is correct. • The smooth surface of the window is reflecting the image of nearby buildings.

22. These answers are not correct because: • A – Prism –light is being refracted as it passes through the prism • B - Rose Quartz – the surface of this rock is too rough to reflect light • D -Paper – since paper is opaque, light would not bounce off or be refracted.

23. Look at the objects below. Which one uses refraction? A B C D

24. Answer Choice C is CORRECT. • A rainbow uses refraction. The light is bent as it passes through the air and water droplets.

25. Answer choice A, B, and D are not correct. Mirrors use reflection of light in order to see an object, not refraction.