PURPOSE: To see convection currents.

DESCRIPTION: The irregular refraction patterns created by convection currents in air heated from below are easily seen when light from a point source (foreground) shines through the air over a hot plate and onto a screen. This phenomenon is often seen when the sun shines brightly onto surfaces like cars and roads, and is responsible for the twinkling of stars.

SUGGESTIONS:

REFERENCES: (PIRA 4B20.45) See also demonstration E2-47: TWINKLING STAR.

EQUIPMENT: Hot plate and point source of light.

SETUP TIME: None.