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A short class with Sarah and her students. The other ways are under More.
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Today we are going to explore how light behaves when it hits a surface. Can anyone tell me what happens when a light ray strikes a mirror?
I think it bounces back!
Exactly! This bouncing back is what we call reflection. Now, when we talk about reflection, we mention two types of rays. Do you remember what they are?
Isn't one the incident ray and the other one the reflected ray?
Correct! And one important angle related to them is the angle of incidence. What do you think that means?
It's the angle between the incident ray and the normal, right?
Yes, that's right! Remember: 'Incident, Normal, Reflected - IN for clarity!'
Always remember the angles of incidence and reflection are equal. Let's mark this concept clearly.
Now, let's perform Activity 13.2. Who remembers how we set up the light experiment?
We put a paper on the table and use a torch and a mirror!
Correct! This time, we will cut the paper and bend it. Why do you think bending the paper is necessary?
To see if it changes how we see the reflected ray!
Great thought! When you bend the paper, if the ray disappears, what does that tell us about the position of the rays and the normal?
They must all be in the same plane!
Exactly! The incident ray, the normal, and the reflected ray all need to align. That's one of the laws of reflection.
The angles of incidence and reflection are equal.
The ray that is coming in to strike a surface.
The ray that bounces back after hitting the surface.
The imaginary line perpendicular to the surface.
For the rays to reflect clearly, they all must lie within the same plane.
When light streams in at an angle that's neat, it reflects the same, that's no trick or deceit.
Once in a land of mirrors, there lived a light ray named Ray. He loved to play with a mirror friend, always bouncing back the way he came, remembering that he and the normal always stay in the same game.
Remember: I=R (Incident = Reflected) to recall the angles.
RIN for Ray, Incidence, Normal.
Term
What is the reflected ray?
Click to flip
Term
What does the normal line represent?
Click to flip
Term
What happens when you bend the paper in the activity?
Click to flip
The ray of light that strikes a surface before being reflected.
The ray of light that bounces off the surface after striking it.
A line drawn perpendicular to the surface at the point of incidence.
The angle formed between the incident ray and the normal.
The angle formed between the reflected ray and the normal.
This section describes an activity that demonstrates the laws of reflection using light rays and mirrors.
The activity highlights the relation between incident rays, reflected rays, and the normal line, reinforcing the concept that these elements lie within the same plane. Additionally, it encourages learners to consider the nature of light reflection and its application in practical scenarios.
In this activity, students replicate a previous experiment to demonstrate the principles of reflection using paper. By observing how light behaves when striking a surface, students learn about the relationship between incident and reflected rays and understand the importance of the normal in these interactions. The activity emphasizes that when the setup is changed, such as bending the paper, the visibility of the reflected ray may be obstructed, illustrating the concept that the incident ray, the normal, and the reflected ray must all be in the same plane for the reflection to occur. This section also encourages students to explore real-world examples of reflection.