Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
Names _______________________________________________________________________
_____________________________________________________________________________
Absent _______________________________________________________________________
It’s a Reflection
When light hits an object, it is reflected. The angle the light makes before it hits the object is called
the angle of incidence. The angle the light makes being reflected off the object is called the angle of
reflection. Think of bouncing a ball. The angle at which it hits will equal the angle at which it
bounces back (45° going in equals 45° going out). The angle at which you throw the ball is called
the angle of incidence, and the angle at which the ball bounces back is called the angle of reflection.
This is also called the law of reflection. It tells us…
angle of incidence = angle of reflection
Variable
Changing angles.
Vocabulary
Analyze (Analysis)
Angle of incidence
Angle of reflection
Data
Evidence
Observe (Observation)
Reflection
Variable
Materials
Protractor
Flat mirror
Hinged mirrors
Laser pointer
Ball
~1~
Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
Activity I – Angle of Reflection
Question
When light hits a reflective surface at an angle, at what angle is it reflect?
Procedure
1. Place a mirror at the bottom edge of the protractor. Use the clay to hold it straight.
Clay
Mirror
Clay
2. Use a laser pointer to shine a light from one angle of the protractor and determine at which angle
it is being reflected. Use Table I.
Laser
Pointer
Clay
Mirror
Clay
~2~
Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
I. Gather (collect data/evidence)
Complete the table as you do the light activity.
Table I
Angle of
Incidence
Angle of
Reflection
20°
60°
80°
40°
70°
10°
50°
30°
II. Reasoning (Analysis/Analyze/What does the data I gathered mean?) Review the
data/evidence in Table I. Write your analysis of what it means.
III. Communication (Conclusion/This is what my data means) Come to a conclusion and
use your evidence from Part II to support your conclusion. You will be answering the question –
When light hits a reflective surface at an angle, at what angle is it reflect?
Part II – Angle of Reflection and Images
Question
How does the number of images change as the angle increases?
Procedure
1. Place a hinged mirror at the edge of the protractor.
~3~
Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
2. Move the hinged part to the degree specified, and place a ball in front of the mirror. Count how
many reflected images you see and complete
“Ball”
Hinged Mirror
I. Gather (collect data/evidence)
Complete the table as you do the light activity.
Table II
Angle of
Mirrors
# of
Images
10°
30°
50°
70°
II. Reasoning (Analysis/Analyze/What does the data I gathered mean?)
Review the data/evidence in Step I. Write your analysis of what it means.
~4~
Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
III. Communication (Conclusion/This is what my data means)
Come to a conclusion and use your evidence from Part II to support your conclusion. You will be
answering the question – How does the number of images change as the angle increases?
~5~
Objective – Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected
color).
~6~