Lab Presentation:
Field of Vision
from The Plane
Mirror
Jin Hyuk Choi, Hyun Su Lim,
Daehan Choe, Namyong Eom
PHY504-01
For Mr. Wilder
What is
the
purpose?
To examine the
field of vision of a
viewer at a fixed
position relative to
a plane mirror
Materials
 1 x Plane Mirror
 1 x a sheet of cardboard or particle
board
 1 x Sheet of paper
 1 x Ruler
 Pins
 1 x A grease pencil
 1 x Protractor
Procedures
1. Place a sheet of paper on the board.
2. Mark a point on the centre of the plane
mirror.
3. Place the mirror at the end of the
paper and mark its position with a line
along the reflecting surface of the
mirror.
Procedures
(cont’d)
4. Draw a normal at each end of the
mirror.
5. Indicate your viewing position on the
paper.
6. Place your eyes at the position
indicated.
Procedures
(cont’d)
7. Look at the point drawn on the middle
of the plane mirror.
- Keep in mind that it is possible to shift
eyes around but the head shouldn’t be
moved.
8. Place the pins into different areas of
the paper in front of the mirror.
Procedures
(cont’d)
9. Find at least three precise points on
each side of the paper at which the pin
just disappears from view.
Mark these points by pinning them on
and out the paper to make a hole on it.
10. Draw lines connecting the points to
the edge of the mirror.
Procedures
(cont’d)
11. Draw a scale diagram of the eye
position, the mirror, and the points
where cannot be seen on the eye
position.
12. Shade the region of vision. This is the
field of vision.
Procedures
(cont’d)
13. By using a protractor, measure the
angle of incidence between the
normal and lines connecting the points
to the edge of the mirror.
Then measure the angle of reflection
between the normal and the lines from
the eye position to the edge of the
mirror.
Data
Data table 1: The mirror size, the location of
the viewing position & the values of angles
Width of the
plane mirror
(cm)
Distance to the
viewing
position (cm)
Angle of
incidence (°)
Angle of
reflection (°)
6.4
26
8
8
Data (cont’d)
• Diagram 1: Field of vision for the plane mirror
Incident ray
Reflected ray
Eye position
Normal
mirror
Analysis
• At the end of the experiment, it
was found out that the field of
vision (the area that can be seen
from the mirror) is the area within
two incident rays in front of the
mirror’s reflective surface.
Analysis (cont’d)
• Relationship during the experiment
- When a normal is drawn at each edge
of the mirror, the reflected rays can be
found from the each edge of the mirror
to the eye position.
- Then, the incident rays to the end of
the mirror can be found. (Angle of
incidence = Angle of reflection)
Able to predict the field of vision
Analysis (cont’d)
• Possible sources of error
- Slight movements of the head
• Suggestion of improvements
- Some tools (rubber sheet etc.)
that hold the observer’s
steadily during the experiment
Conclusion
• In the experiment, how was field of
vision of the viewer observed?
• According to the data, what
influenced the field of vision of the
viewer?
• Through this experiment, what have
we learned?
• What kind of application that is
related to the field of vision exists?