11.7 Images in Plane Mirrors

11.7 Blog: Images in Plane Mirrors


Today in our Science Class we went over 11.7, "Images in Plane Mirrors". We learned many new interesting concepts in this class. First we learned how light rays are used to locate images in mirrors. A light source emits millions of rays that bounce of a mirror. You will only see the rays that bounce back into our eye. Light travels in nothing but straight lines. And when your eyes look at a mirror it seems as if the mirror is a light source but it actually is not. Mirrors are opaque. This is how you see things reflected on to a mirror. These things are called Virtual Images. We also can use this knowledge to create equal perpendicular lines and locate an image on a mirror by ourselves. You just draw the incident ray coming from your object and then you draw your reflected ray. You can easily draw the reflected ray using a protractor without a real light source because we know the angle of incidence and the angle of reflection is always equal.
After this you trace the reflected ray behind the mirror and you can see where the object would be on a mirror by seeing when the extended reflected rays connect. This is really cool to me as you can draw an exact reflection o
f an image by yourself at home just by using a pencil and a protractor! Two observations you can get from this is that the distance between the object and the mirror is the same distance between the virtual image and the mirror. Another thing is that the object-image line is perpendicular to the mirror surface. These are some of the interesting things we learned today about images

in mirrors.

If you need more help understanding and doing this, Watch this interesting video!

Another Important thing we learned in class is how to describe the properties of an image! You can do this by using the acronym called SALT, which stands for:

Size of the image compared to the object

Attitude of the image(orientation)
Location of the image
Type of Image(Real or Virtual)
















Overall this was a great class in which we learned many interesting things!
By: U.Q and H.M

11.6 The Law of Reflection and Plane Mirrors

11.6 Blog: The Law of Reflection and Plane Mirrors

Diffuse Reflection

Today we learned about chapter 11.6 which was about the laws of reflection and plane mirrors. Light travels in a straight line. A light ray is a line and arrow that represents the path of light. Reflection is light bouncing back from any surface. However a mirror is the most commonly used way to reflect light, in this video it shows us how this is done. A mirror is any polished surface that reflects. Specular reflection (picture) is the reflection of light off a smooth surface. Diffuse reflection (picture) is the reflection of light off a surface that is not smooth.

          

 

Laws of Reflection

1. The Incidence angle equals the angle of reflection, so basically the angle between the incident ray and normal is equal to the angle between the reflection rays and normal.



Incidence Angle = Reflection Angle

2.   The Incident ray, reflection ray and the normal all lie on the same plane

By: N.M. & T.C.

11.3 The Ray Model of Light

November 2013,

On 11.3 we learned about the Ray Model of Light. Here’s a  short recap on what we learned from 11.3:

Figure 1

Light rays is  a line that represents the direction and path that is travelling(Figure 1). The use of light rays to determine how light behaves when it strikes objects is called geometric optics. When drawing rays, you do not need to draw it at every angle, you would only need to draw a few like the example shown in figure 1. 

Figure 2 (a) example of opaque, (b) example of transparent, (c) example of translucent

If a emitted light reflects off an object we call it incident light. when the sun emits light and the moon reflecting the light is an example of incident light. A clear material in which you can see through is called transparent . An example of a transparent object would be windows, raindrops, water. A material that transmit lights through but cannot see objects through the material is called a translucent. Example of translucent would be jello, piece of thick plastic, x-rays.  A material that does not transmit incident light is called opaque. Example of opaque is pudding, cardboard box, brick.

Flat Mirrors

Figure 2

A reproduction of an object through the use of light is called an image. Any surface that reflecting a image is called a mirror. when the light bouncing back from a surface is called a reflection. 

Mirrors are made up of two major parts: a thin layer of shinny film, that is the reflective surface, and the thick layer of glass that goes over the film to protect the film from scratching (Figure 2). 


The Terminology of Reflection

Figure 3

To illustrate how predictable the path of light is when it hits the mirror they use a plane mirror, plane meaning flat. The incoming ray that strikes the mirror first is called an incident ray (Don't get confused between incident ray and incident light). And the ray that is reflected from the mirror is called a reflected ray. The line that is perpendicular to the mirror is called a normal. The angle between the incident ray and the normal is called angle of incident. And the angle between the reflected ray and the normal is called angle of reflection. when measuring the angles, you need to make sure that the incident line is pointing to the normal. And also make sure that the normal and the mirror is perpendicular to the normal. 




If you're still having troubles understanding some parts of the lesson, here's a video that may help you understand better:

http://www.neok12.com/php/watch.php?v=zX55506f6d5e64527161720a&t=Light-Optics



By: V.E. & J.C.