We know that light bounces. This activity allows students to uncover and explore the a strict rule about how it bounces: The Law of Reflection.
Grades: 3 to 12
Duration: 1/2 Hour – 1 Hour
Supplies: A single Light Blox with the slit cap on, Masking tape, Aluminum foil, A small mirror and mirror stand, A large mirror
PUT THE LINE CAP ON the front of the LightBLOX. Move the line of light so that it hits the mirror at an angle. Move the light again.
What happens to the bounced beam when you move the light?
Attachments: Lesson – Challenge Reflection V2 copy.pdf
This video walks you through the background information you may need for teaching about the Law of Reflection
Pick a spot on the table not too far from the mirror. Can you shine the light at the mirror and make the light bounce to that spot? Move the mirror and the light until you can.
Law of Reflection
You need to work with a partner to do this activity. Find a place where there is a wall with plenty of space around it. Attach the mirror at eye level on a wall with masking tape. Cover the mirror with a piece of paper.
Now, both you and your partner should try to guess where you both need to stand to see each other’s reflection on the mirror. When you both agree on the places, mark them on the floor with 6-inch pieces of masking tape.
Remove the paper from the mirror. Stand at your chosen place to determine if you can see each other in the mirror.
If you can’t see each other, try different places until you can. Mark the places that work with the 6-inch pieces of masking tape.
Next, place long pieces of masking tape on the floor from the center of your 6-inch place markers to the wall straight under the center of the mirror. These should be straight lines.
Look at the angles made by the taped lines on the floor and the wall to see if they are the same size. Remember that light bounces off a mirror at the same angle that it arrives. Therefore, when the light from your face travels to the mirror on the wall, it should bounce off the mirror at the same angle to the eyes of your partner.
On a sheet of paper, write a description of what you did in this activity. Include a diagram with lines showing how light reflects off a mirror.
So Many Reflections
With simple mirrors, light reflects in a predictable way. But most objects aren’t simple mirrors. What happens when light bounces off of ordinary objects?
Start with a sheet of very shiny aluminum foil and a LightBLOX with the line cap on.
Fold the foil a couple of times to create a small “mirror”.
Can you see a reflected beam? How is it different from the beam from the “real mirror”?
Now crumple up the foil into a ball. Shine the beam at the foil.
What do you see? What’s happening? Can you see “a reflected beam”?