Chapter Two Demonstrations

READING: Seeing the Light, pp. 28-55


3-M Brand Privacy screen illustrates that light travels in a straight line through its micro-venetian blinds.

Pikachu under glass


Varying the angle of incidence varies the angle of reflection to scan a laser beam across the paper in this Laser Printer Scanner Head.

Laser print head guts

Spinning mirrors not perfectly aligned with the motor shaft make interesting patterns.

Junk turned into fun

Close up of the arrangement:

Close up of junk turned into fun

A supermarket checkout scanner mirror assembly and a galvanometer scanner combined to make a Laser Oscilloscope:

More junk into fun

An orthogonal pair of mirrors allows you to see yourself in the orientation that others do.

Mirrors in a corner vise

What you see

Partial reflection allows a candle to burn under water:

It's all done with mirrors

Another use for semi-reflecting mirrors:

Infinity from above

Infinity headon

In the middle of infinity


Finding Total Internal Reflection in an isoceles right triangular prism retroreflects the beam into a U-Turn. (Photo Credit, Allen Winston, HCD Class 2009)

Critical Angle U-turn

Meeting or exceeding the Critical Angle traps a laser beam in a stream of H20. (Photo Credit, Allen Winston, HCD Class 2009; Apparatus built as a Final Project by Britt Black, HCD Class 2008.)

Not a waste of a liter graduate!

Other critical angle demonstrating devices:

Light Pipes Galore!

More demonstration devices from this Chapter:


more junk

How does the holographic incident angle finder work?
What is the test to determine if a source is a point?
Could you see the pinholes in the pinhole cameras?
What is the angle of the reflected ray compared to the incident ray?
What is the basic principle of the laser scanning light show?
Were you fooled by the "rabbit" box?
Where does the light go after having been bounced by a pair of mirrors at right
angles to each other? with 45 degrees between them?
What happened when you looked in the right angled mirrors?
What do you see when you look in a corner cube?
Why aren't bicycle retroreflectors made perfectly?
What is the difference between the day and night images in an automobile rear
view mirror?
What is the difference between specular and diffuse reflectors?
When does a diffuse reflector become a specular one?
Is the amount of light reflected from a piece of glass constant at all angles of
When does the light reflected off glass become stronger than the light transmitted
through it?
How does light bend going in and out of the plexiglass pieces?
What happens to the view when tilting the large plexiglass block?
How does Edwal No©Scratch work?
Which equilateral prism bent light more, the solid plastic one or the water©filled
What was seen in the two different ways of looking through the Dove (erecting)
Why did the light stay in the stream of water?
What did the fiber optic launching mechanism look like?
How is the image transmitted in the TV Rock and endoscope?
How was the dispersing prism held when viewing the flourescent lights?

Maybe one of these days there will be images for all these demonstrations!

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