Interactive Lecture Demonstration: Convection current in air

by Erees Queen Macabebe and Ivan Culaba
Department of Physics, Ateneo de Manila University

Candle, mosquito coil, matches, and a transparent box with two chimneys

Objective

Demonstrate convection of heat in air.

Description of the Set-Up

The set-up consists of a transparent box with two chimneys, a candle and a mosquito coil. The match is used to light the candle.

Demonstration

Light the candle and place it inside the box near the opening of one of the chimneys. Light the mosquito coil until it glows red then put off the flame. With the box closed, place the mosquito coil near the top of the second chimney.

Observe what happens to the smoke coming from the coil.

The lighted mosquito coil is placed near the opening of the second chimney.  Where did the smoke from the mosquito coil go? Why?

A lighted mosquito coil about to be placed on top of the chimney that has no candle

A lighted mosquito coil placed on top of the chimney that has no candle