Light and Angles
The lesson will focus on students’ discovery of light reflection from a mirror through use of inquiry based methods. This lesson fulfills the California State Standards for Fourth Grade Physical Science 2:
Light has a source and travels in a direction and Students know light is reflected from mirrors and other surfaces.
Students will predict, test, and explain what happens to light when it is reflected on a mirror through investigation of the path of the light at different angles.
- Front board and pens
- 12”x12” mirrors for pairs of students
- Maze worksheets (PDF)
- Black cloth draped on the wall of the classroom
- Flashlights for pairs of students
- Desk light
- Mirror reflections worksheet (take home)
- Six 48” pieces of string
- Students will sit in groups of four to five and have two 12x12
mirrors set in the middle of the table.
Ask students What was difficult about using the mirror to complete
a maze? Write down student responses on the front board. Some responses
may include that the maze looks different than it really is or that when you
move the pen one way it goes the other way. If students hit these main ideas,
the teacher will discuss the idea of reflection further.
- The teacher will ask the students, What do we use mirrors for in
our everyday lives? Students can share answers and create a list on
the front board. Once a variety of answers is conveyed, the teacher will
pass out a maze for each of the students.
- The teacher will ask the students What would happen if we could
only see using a mirror? Do you think it might be difficult
doing certain tasks? Urge students to try to complete the maze using
the mirror. One student partner can hold the mirror as another student attempts
to complete the maze.
- Once students have completed the activity, display the mazes on the front
board so the class can visualize how difficult it is to use a mirror to
complete a task.
Pass out the flashlights to the students and point out the black cloths
around the room.
- The teacher can inform the students that the mirror is used to reflect
the image of an object. Give the students an example of looking in the mirror.
Tell them When you look in a mirror, you are looking at an image of
yourself in the mirror
- Ask students Have you ever seen a reflection that was not in a mirror?
Wait for a response. Lead students thinking to What about in the evening
at the beach? What do you see in the water? Students should respond
to the sunset in the water as a reflection. Inform students that the light
from the sun hits the water and reflects to create a pretty sight.
- Ask students Do you think light can reflect off of something other
than water? Students may respond to several ideas, but focus back
Tell students that tonight they will try to use a flashlight in a mirror
with their parents. Ask them to draw a picture of what the path of the light
looked like and bring the picture back to class the next day. Pass out the
worksheet that they will use to create the pathway of the light.
- Write the following focus questions on the front board:
Is light reflected in a mirror?
Where is the light reflected?
If the light is moved into different locations, does the reflection look
- Turn off the classroom lights and keep a small desk light lit for students
to still see within the classroom.
- Move about the classroom and redirect students investigations if
they only point the flashlight at a 90º angle. Ask these students What
do you think would happen if you turned the flashlight a little to the right
or the left?
- Once each pair has discovered the reflection on a mirror appears in the
opposite direction turn the lights on.
- Ask for a few student volunteers to describe what the path of the light
looked like when they pointed the flashlight in certain ways. Draw examples
on the front board.
Ask students What do you think would happen if light was reflected
onto the mirror when you turn the flashlight to the left? Give students
time to think and then demonstrate the direction without turning on the flashlight.
Ask student volunteers to show the class the direction they think the path
of light will go.
- Collect the worksheet for further assessment of the reflection concepts.
- Ask pairs of students to come up to the front of the room and hold string
where they think the path of light will reflect off the mirror that is sitting
in the front of the classroom.
- Give students the opportunity to work together to place their string,
having one student hold one end of string near the mirror and the other
move in the direction they assume the light will go. Have a few pairs of
students stay up in the front of class to test their predictions.
- Turn off the light in the classroom and determine which pair of students
was most accurate.
- Have students return to their seats and ask How can you predict
which way the light will go if you hold the flashlight a certain way?
Give students the opportunity to show their understanding of the path of
light reflection against a mirror. Write down responses on the board.