# Reflection and Refraction

## Presentation on theme: "Reflection and Refraction"— Presentation transcript:

Reflection and Refraction
(5.6C) demonstrate that light travels in a straight line until it strikes an object or travels through one medium to another and demonstrate that light can be reflected such as…

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. next

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. next

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 light and absorb the light that is not reflected. Smooth, shiny surfaces that absorb very little light, will reflect light in almost the exact way that the light hits it. Smooth, shiny surface next

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

Refraction When the path of the light rays change directions and appear to bend as they pass through an object, we call this refraction. Refraction occurs when light passes from one substance to another of a different density (for example, from air to water). The amount of refraction depends on the angle that the light enters the new substance and the difference in the densities of the two objects. The greater the angle, the more the light ray will be bent. next

Refracting telescopes and regular cameras use lenses to gather and focus light.
Reflecting telescopes gather and focus light with mirrors. In a reflecting telescope, the observer usually sits inside the telescope, at the focal point of the reflected light. next

Decide whether each object below best represents reflection or refraction. Click on your answer to find out if you are correct. reflection refraction reflection refraction reflection refraction reflection refraction reflection refraction reflection refraction next

You are correct – This picture illustrates reflection
You are correct – This picture illustrates reflection. Light bounces off of the object and does not pass through. Back to pictures

You are correct. This picture illustrates refraction
You are correct. This picture illustrates refraction. As light passes through the object it is bent by the denser substance. Back to pictures

Sorry, that is not correct
Back to pictures

A transparent object lets all of the light pass through.
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 none of the light pass through. transparent translucent opaque next

You are about to see several objects
You are about to see several objects. Your job is to decide if they are mostly transparent, translucent or opaque - After you decide, click on the object to see if you are correct. Some pictures have two options. These pens are translucent. Enough light passes through to allow you to see some of the inside, but not enough to see everything clearly. This window is transparent. You can clearly see the image on the other side because all of the light is passing through. This sphere is transparent. You can clearly see the man inside. The man, of course, is opaque. The computer is opaque. No light is passing through, so you cannot see anything behind it. However, the screen is transparent. That is why you can clearly see the man’s face behind the screen. The brick wall is opaque. You cannot see any part of the boy through the wall. This lampshade is translucent. Some of the light passes through, but not all of it. The next image will enter automatically. Do not click to advance images. next

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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. next

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

All the following are examples of light being refracted EXCEPT —
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DID YOU NOTICE THE EXCEPT IN THE QUESTION?
Answer choice D is correct. The mirror is using reflection to bounce light off of its surface. DID YOU NOTICE THE EXCEPT IN THE QUESTION? next

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. next

Which answer below names two conditions in which refraction can occur?
Opaque or transparent Transparent or black Translucent or transparent Translucent or opaque next

In order for light to pass through an object and be refracted, the object must be transparent (see-through) or translucent (semi-transparent). next

These answers are not correct because:
Answer A - An opaque object would not allow light to pass through it. Answer B – A black surface would not necessarily allow light to pass through it. Answer D – An opaque surface would not allow light to pass through it. next

In this picture, the straw appears to be bent. This is because –
milk is an opaque substance. light is traveling through the air into the water. it is a magic trick. light is bouncing off of surface of the water. next

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

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. next

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

Answer C is correct. The smooth surface of the window allows the light rays to bounce off of the water reflect the image of nearby buildings. next

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. next

Look at the objects below. Which one uses refraction?
D next