TODAY’S OUTCOMES:
BEHAVIOR OF LIGHT
- Discuss and review the Law of
Reflection
- Construct and use a pinhole camera
- Study the range and angle of visibility
of mirrors
Give a rule for reflection telling how the directions of the incident and reflected light beams are related
For a light beam on a mirror, the angle of incidence equals the angle of reflection:
Give a rule for reflection telling how the directions of the incident and reflected light beams are related
For a light beam on a mirror, the angle of incidence equals the angle of reflection:
This top view diagram shows a light beam coming straight out from a light station.
There is a mirror off to the side not doing anything. You can move the mirror anywhere
that you want in the picture. Draw the mirror somewhere in the light beam, showing it
turned at the correct angle so that the beam is reflected and goes through the black X.
Draw the reflected beam, too.
This is not the ONLY position the mirror can be in..........
This top view diagram shows a light beam coming straight out from a light station.
There is a mirror off to the side not doing anything. You can move the mirror anywhere
that you want in the picture. Draw the mirror somewhere in the light beam, showing it
turned at the correct angle so that the beam is reflected and goes through the black X.
Draw the reflected beam, too.
This top view diagram shows a light beam coming straight out from a light station.
There is a mirror off to the side not doing anything. You can move the mirror anywhere
that you want in the picture. Draw the mirror somewhere in the light beam, showing it
turned at the correct angle so that the beam is reflected and goes through the black X.
Draw the reflected beam, too.
There is no limit to the number of positions the mirror can
be in, so long as it is rotated correctly.
This top view diagram shows a light beam coming straight out from a light station.
There is a mirror off to the side not doing anything. You can move the mirror anywhere
that you want in the picture. Draw the mirror somewhere in the light beam, showing it
turned at the correct angle so that the beam is reflected and goes through the black X.
Draw the reflected beam, too.
“vertical angles”
are equal
Explain how you determined where to put the mirror and how to turn it.
The mirror can be in any location along the light beam; the correct angle can be
found by rotating the mirror such that the mirror cuts the angle between the light
beam and the desired reflected beam exactly in half.
Here is a small light source and a mirror. Three light beams are directed towards the
mirror. Determine where they are going after they reflect.
Remember - the direction of reflection
and the location of images are not the
same thing
A common error is to
try to place the
beams at 90° angles,
because you can
see images ‘off to the
side’
WRONG
We will investigate formation of
images in the next couple class
sessions
Reflection from mirrors at a right
angle
If you measured the angles carefully, you saw that the reflected
beam is parallel to the incident beam after 2 reflections.
Reflection of sunlight in a well:
Seeing a reflection of the sun at the bottom of a well is only
possible if the sun is (almost) directly overhead!
*This observation will be brought up again later...........
WHAT YOU ARE EXPECTED TO KNOW:
- The Law of Reflection: The angle of incidence
equals the angle of reflection
- How to determine how to situate a flat mirror to
reflect light in a particular direction
- How to trace the path of a light beam reflecting
from multiple mirrors
TODAY’S OUTCOMES:
BEHAVIOR OF LIGHT
- Discuss and review the Law of
Reflection ✓
- Construct and use a pinhole camera
- Study the range and angle of visibility
of mirrors