6A10.60 Candle in a Beaker of Water
Reflection, plane mirrors, transmission
A candle appears to be underwater by superimposing the transmitted light from the beaker with the reflected light from a candle. A pane of glass between the candle and the beaker acts as both the transmission medium and the mirror.
This illusion is also known as Pepper's ghost.
-  Beaker
-  Container of water
-  Candle
-  BBQ lighter or book of matches
-  Black fabric
-  Desk lamp
-  Black metal plate
-  White background on a stand
-  2-poled lab stand
-  90-degree clamp
-  Pane of glass
-  Magnet
-  Camera
-  Fire extinguisher
- Attach the 90-degree clamps and magnets to the lab stand to make a holder for the pane of glass. Put the glass in.
- Place the candle and beaker such that they overlap.
- Use the metal plate to block the candle from the audience and block stray light sources.
- Adjust the lighting as desired using the black cloth, white background, and the desk lamp.
- Focus and zoom the camera on the beaker. Ideally, the field of view doesn't show any edges of the glass.
- Do not place the black fabric anywhere above the candle. The fabric can melt or catch fire.
- Fire is dangerous. Do not run this experiment near anything highly flammable. Be prepared to evacuate, if necessary.
- Remember you have a fire extinguisher if an uncontrolled fire starts. Refresh yourself with the fire extinguisher controls, if necessary.
- Turn off the room lights.
- Activate the camera.
- Light the candle.
- Point out the candle "inside" the beaker.
- Pour water into the beaker so that the candle appears submerged.
- Blow out the candle and explain the actual arrangement of the objects in the demonstration. Explain the illusion is sometimes used in stage productions or carnival attractions.
- PIRA 6A10.60
- Don't attempt this at home!
If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.