Mrs. Hughes
Date: __________
“Shadow Lab”
Name: ____________
Core #: ________
Research: Read p.288-289 + 294-296 then define:
Light
Shadow
Umbra
Penumbra
Opaque
Translucent
Transparent
Part 1: Making shadows and playing with light source angles.
Materials: Light source (Flashlight), block, & ruler.
Procedures:
A. Explore making Shadows.
1. Get a flashlight and a block. Shining your flashlight at the block can you make the
following shadows on the wall? Answer yes or no.
a) square: _____________ b) rectangle: ____________
b) diamond: ___________ d) sphere: ______________
2. Put the block on the lab counter (table). Shine a flashlight at the block from different
angles and different distances to the block. Try to make the following shadows in the
table below. Sketch your set up for each result. Instead of drawing a flashlight draw an
arrow to represent the angle the light source was at. Also describe the distance the light
source was from the block (ie. close or far).
Shadows
Larger than
object
Drawing: include object,
shadow, and angle of
light source. (Sketch)
Distance from
light source to
object.
(Closefar)
Shadow
Other notes
formed on
wall, counter
or both
Smaller
than object
Dark
shadow
with sharp
edges
Lighter
shadow
with fuzzy
edges
B. Can you make a sun dial?
1. Use a flashlight and an object to recreate how a sundial works? (Hint: The independent
variable is the angle of the light source -all of variables should be constant including the
light source distance to the object.)
Question:
1. What did you discover about the angle of light source versus the size and direction
of the shadow?
2. Predict and draw what a shadow would look like first thing in the morning, lunch
time, and dinner time. (Assume it is summer time). Draw the sun (light source) as an
arrow, object, and shadow produced.
Morning
Lunch
Dinner
PART 2: Measuring Shadows:
Equipment: ray-box, rubber stopper, & ruler
A. Procedures: Change the distance of the object to the light source
1. Place the light source and screen at a fixed distance apart on the counter top.
Record this distance= _________
2. Put the object at different distances between the light source and the screen. Measure
and record the distance between light source and object.
3. Measure the size of the shadow.
Trials
Distance from
Light source to
Screen
(Constant)
Distance from Light
source to Object
(Independent
variable)
Size of object
(Constant)
Size of Shadow
(Responding
Variable)
1
2
3
4
Questions:
1. Does the size of a shadow have any relationship to the distance an object is from
the light source? Explain.
2. To create a large shadow, should you have the object closer or father away from
the light source?
Bonus: Can this relationship also be stated in mathematical terms?
B. Procedures: Change in light source to screen distance
1. What would happen if the light source is moved to varying distances from the screen,
but the object is held at a constant distance from the screen?
* Do this activity and fill in the table below.
Trials Distance from
Distance from the Size of object Size of Shadow
Light source to
Object to the
(Constant)
(Responding
Screen
screen
Variable)
(Independent
(Constant)
variable)
1
2
3
4
1. Does the size of a shadow have any relationship to the distance an object is from
the light source when the object’s distance to the screen is constant? Explain.
2. To create a large shadow, should you have the light source closer or father away
from the object?
Part 3: Single point of light vs two light sources
If you have a large light source, it can act as if there is more than one point light source.
The shadows that are created are both an umbra and penumbra. (see p.294)
Materials: 2 Ray-boxes, rubber stopper, white paper, pencil, & ruler.
Procedures:
1. Put a rubber stopper on a piece of paper. Trace and label the rubber stopper. Aim two
light ray boxes at the rubber stopper. Trace and label the ray-boxes. Use a ruler and a
pencil to trace the umbra and penumbra created. Shade in the umbra darker than the
penumbra. (see p.295 procedure 5)
2. Play with the two light source angles and object(s). Try to find interesting shadow
formations. Draw the most interesting shadow formation on the back of the white sheet
of paper.
3. Staple the shadow label and drawing sheet to the lab.
Conclusion: Write a summary of what you have discovered in this lab. Include the
following points. You may also include diagrams to help explain your findings.
1. What is the property of light that allows shadow to form?
2. What is the property of the objects used that allows shadows to form?
3. Explain the difference between a penumbra and umbra.
4. How would you create a large shadow for movie special effects?
5. How could you manipulate shadows for a piece of art? (Hint: light source angles +/or
multiple light sources?
6. What do you wonder about making shadows? Is there a further experiment or idea you
would like to explore?