Disappearing Beaker

Optics > Refraction > Index of Refraction

DCS# 6A40.30

DISAPPEARING BEAKER

APPARATUS

Pyrex 600 ml beaker	101-01-C
Pyrex 100 ml beaker, no grads	101-01-C
Johnson's baby oil	202-21-C
black cloth for background	202-21-B
video camera	102-09-D

DESCRIPTION

The index of refraction of baby oil is nearly equal to that of Pyrex. When baby oil is poured into the inner beaker and allowed to overflow into the larger beaker, the immersed part of inner beaker disappears.

NOTES

Glass must be cleaned thoroughly.

Stick cloth to the board with magnets.

Other possible liquids include wesson oil, glycerine/water mix.
Or quartz or lucite in glycerine.

Variations:
Rest coin on submerged glass object so it appears to be suspended in the liquid.
Half fill bottle with eyedropper and pass around.

REFERENCES

Sutton, L-33.

TPT 15, 438 (1977).