OO
n summer evenings Kamal and his family used to eat their
evening meals in the garden. One summer evening, as they
were getting up from the table, Kamal saw a light going on and off
amongst the trees at the edge of the garden. He went over to the
trees to see what was going on, and he noticed an insect flitting
about. But this insect was very different from those he was used to
seeing in the daytime. It was giving off light as it flew.
The insect stopped flying for a moment, and came up to Kamal.
"Hello," it said. "You look very surprised. You've been watching
me for a long time. My name's Glow-Worm, what's yours?"
"My name's Kamal. You're right, I've never seen an insect that
flickered with light in the way you do before. Yellowish green rays
are coming from your body. I remember that once when I touched
a light bulb it burned my hand. Doesn't having this light coming
from your body hurt you?"
The glow-worm nodded. "You're right,
Kamal, when you say that lamps are
really very hot while giving off light.
Light bulbs use electrical energy to
produce light, and some of that en-
ergy turns into heat. That causes
the bulb to become hot. But we do
not take energy from outside for
the light that our bodies give off."
Kamal thought he understood.