make a periscope

Explorer Education Programme
Lesson Plan: How does a Submarine see above the Water?
Make a Periscope
HOW DOES A SUBMARINE SEE ABOVE THE WATER?
MAKE A PERISCOPE
Aim / Description:
In design and making students can learn about the reflection of light by making a
periscope.
Background:
A submarine under the water uses a periscope to see above the water. The word
“Periscope” comes from the Greek words, “peri” which means "around," and
“scopus” which means, “look."
A periscope can be used to see over high objects and around corners. A periscope
uses two mirrors facing each other to bounce reflections between them. Light
reflects away from a mirror at the same angle that it hits the mirror. In a periscope,
light hits the top mirror at a 45-degree angle and reflects away at the same angle,
which bounces it down to the bottom mirror. That reflected light hits the second
mirror at a 45-degree angle and reflects away at the same angle, right into your eye.
The longer the tube of a periscope, the smaller the image will be. Periscopes in
submarines have magnifying lenses between the mirrors to make the reflected
image bigger.
For marine related lesson plans, worksheets and activities see
www.marine.ie

Explorer Education Programme
Lesson Plan: How does a Submarine see above the Water?
Make a Periscope
Materials:
• Two small pocket sized (flat square mirrors are best)
• A piece of strong cardboard 1 foot x 1 foot (30cm x 30cm)
• Strong tape
• Pencil / Pen
• Ruler
• Scissors
• Items to decorate the periscope
Activity: Make a Periscope
Step 1. Discuss with students how submarines use a periscope to see outside.
Step 2. Give step-by-step instructions and the diagram showing how to make a
periscope:
o Form a circular tube using cardboard and tape it together.
o The tube needs to be cut to fit the mirrors into the tube and viewing holes are
required. Therefore, lightly flatten the tube so you can draw an outline of
where the tubing needs to be cut (see illustration below).
o Draw a circle at the top of the tube smaller than the mirrors.
o Draw a circle at the bottom of the tube on the opposite side of the tube i.e. big
enough for an eye to see through.
o Draw a slit above the circle at the top of the periscope (approximately a 45-
degree angle from the top). The opening of the slit is to be above the circle
and should be big enough to put a mirror in facing towards the bottom of the
periscope – do not cut right across the tube.
o Draw a slit at the bottom of the periscope at the same 45-degree angle as the
slit at the top. The slit should be below the circle at the bottom. The opening
of the slits should be on the same side of the tube.
o When the correct markings are made - cut them out.
o Fit one mirror into the bottom of the tube facing upwards. Holding up the
tube, view through the hole at the bottom. You should see the ceiling. (If you
cannot see the ceiling - readjust the angle of the mirror.)
o Fit the second mirror into the top slit of the tube facing downwards. The
mirrors should be at 45-degree angles facing each other. Tape them into the
slits so they do not fall out.
Step 3. Encourage the students to test their periscopes by looking through the
viewing hole. Get the students to sit under their desks and observe what can be
seen.
Step 4. Get the students to paint and decorate their periscope.
Outcome:
Students will have developed skills:
• understanding how periscopes work using the science of reflection
• understanding angles and calculations.
• using their imagination and creative skills making and decorating their own
periscope.
For marine related lesson plans, worksheets and activities see
www.marine.ie

Explorer Education Programme
Lesson Plan: How does a Submarine see above the Water?
Make a Periscope
Illustration showing the holes and slits needed to make a Periscope.
Cut slits in the tube at
right angles large
enough to fit the
mirrors.
Cut the hole at the
top of the periscope
under the slit.
Place mirrors into the
slits facing each other.
Cut the hole at the
bottom of the
periscope above the
slit.
For marine related lesson plans, worksheets and activities see
www.marine.ie