Related Phenomena
At night, with the lights on inside your house, you look at your window. Instead of the seeing the yard, you mostly see ________. (Lesson 1 & 3)
Your own reflection.
This black opening in the center of your eye is where light enters. (Lesson 6)
The pupil
Glass, regular mirror or one-way mirror: which one transmits the MOST light? (Lesson 3)
Glass
When light bounces off a material, we say the light is _______. (Lesson 3)
Reflected
True or false: glass, a regular mirror and a one-way mirror ALL reflect at least some light. (Lessons 3 & 4)
True!
Looking into a clear, still lake, you can see through to the rocks on the bottom AND your own reflection on the surface of the water. How is this like our one-way mirror phenomenon? (Lessons 1 & 3)
HINT: What two things is the light doing? It is found in our vocabulary.
Some light transmits through the water (you see the rocks) and some reflects off the surface (you see your reflection).
This clear part of the eye "bends/funnels" light so it is able to focus on the back of the eye. (Lesson 6)
HINT: Think about our magnifying glass example!
The lens
To make a mirror, manufacturers coat glass with a layer of this shiny metal, which reflects light. (Lesson 4)
Silver (Also Acceptable: Aluminum, Tin, Nickel)
When light passes through a material, we say the light is _______. (Lesson 3 & 5)
Transmit or Transmitted
Which light setup makes the one-way mirror effect the STRONGEST:
- Bright on both sides
- Bright on one side, Dim on the other side
- Bright on one side, no light on the other (completely dark)
(Lesson 5)
Bright light on one side, no light on the other.
The bigger the difference in light levels, the stronger the effect.
When your phone screen is off, you can see your reflection in it. When the screen is on, you see the screen display instead. Why?
(Lessons 1, 3, 5 & 6)
When the screen is on, it gives off much more light than the light reflecting off your face.
Your brain goes with the stronger signal, so you see the screen.
This part at the back of the eye changes light into an electrical signal. (Lesson 6)
The retina
What does one-way mirror film look like under a microscope? (Lesson 4)
HINT: Think of our reading we did in Lesson 4!
The film has an even distribution of half silver and half plastic laid out in a checkerboard pattern.
Light reflects off the silver parts and transmits through the clear gaps.
Of the materials we measured with light meters in class, which material reflected and transmitted light somewhat equally?(Lesson 4)
HINT: Look at our "Classroom Data Table" if you are stuck.
The One-Way Mirror
Pete has two light inputs entering his eyes. Name where each one comes from and which one is stronger. (Lesson 5)
1) Light that reflects off Pete, then off the mirror, back to his eyes (stronger).
2) Light that reflects off the teacher and transmits through the mirror (weaker).
On a sunny day, the driver in a car with tinted windows can see out of their car, but you can't see in. Explain why.
(Lessons 1 & 4)
It's much brighter outside than inside the car. You mostly see light bouncing off the window. Lots of outside light goes through the window to the driver.
You walk out of a dark movie theater into bright sunlight. What does your pupil do, and why? (Lesson 6)
Your pupil gets smaller to let less light in, which protects the retina from too much light and allows you to process what you are seeing.
(In the dark it gets bigger to let more light in. In the light it gets smaller to let less light in.)
A regular mirror has two layers behind the glass. Name them and tell what happens to the light that hits it. (Lesson 4)
HINT: If you are stuck, page 29 is a good place to start with your search.
A thick silver layer and a paint layer.
All (or almost all) of the light reflects off the silver layer.
The paint/backing stops any other light from transmitting through.
Why does glass reflect a small amount of light?
(Lessons 3 & 4)
The light mostly transmits, but it also reflects off of the dust and impurities on/in the glass.
Someone turns on bright lights in BOTH rooms. What can the music student see now, and why? (Lesson 2)
HINT: Think of our Box Model Investigations.
The student can see the teacher.
Much more light reflects off the teacher and transmits through the mirror, so that both inputs are now strong enough to see.
When you look at someone wearing mirrored sunglasses, you see yourself, but they can still see you. How are the lenses like a one-way mirror? (Lesson 4)
The lenses have a thin reflective coating. Some light reflects (you see yourself because bright light reflects off you), and some transmits through to the wearer's eyes. Little light comes from the shaded side by their eyes, so you can't see them.
Put these in order, starting when light enters your eye: brain, lens, optic nerve, pupil, retina.
(Lesson 6)
Pupil → lens → retina → optic nerve → brain
A light meter on the far side of three materials reads:
X = 0 lux
Y = 410 lux
Z = 850 lux
Match each to glass, regular mirror or one-way mirror. (Lesson 3)
HINT: They are measuring the light that transmits through each material. Look at your "Classroom Data Sheet" if you are stuck.
X = regular mirror, Y = one-way mirror, Z = glass
Light that reflected off the music teacher DOES reach the music student's eyes. So why doesn't the student see the teacher? (Lessons 5, 6, and 7)
HINT: Our classroom consensus model!
Very little light reflects off the teacher in the dark room. Much more light reflects off the student, bounces off the mirror and enters their eyes.
The brain responds to the stronger light signal!
How could you change our example to make Pete see the teacher, and the teacher see their own reflection?
(Lessons 2, 6 & 7)
Switch the light source to be in the teacher's room as opposed to Pete's room.
Now, instead of Pete's reflection being the strongest, it is the teacher's.