Illinois Natural History Survey - University of Illinois

The Naturalist's Apprentice: Communicate With Light

Both male and female fireflies flash lights to attract mates. These "cold" lights are produced by a chemical reaction within the abdomen of the firefly. The males fly close to the ground and emit flashes of light while performing acrobatics. Each species has its own characteristic pattern. For mating to take place, the female firefly (of the same species as the flashing male) must respond with pulses of light at exactly the correct time interval after the male's flashes before he will fly over to her to investigate.

light.jpg

You can learn to communicate with flashing lights similar to the way fireflies do. All you need is a flashlight (one with a button that you push to turn it on and that will turn off when you release it works best) and a knowledge of International Morse Code (shown below). Practice the letters shown below by shining the flashlight on a wall in front of you so you can easily see a spot of light. For a dot, press and release the button on the flashlight quickly. For a dash, hold the button down longer, usually three times longer than you do for the dot. Pause between letters (a pause about the length of time as a dash works well), and pause at least three times longer between words. Try learning a few simple words first, your name, and then a short sentence.

Practice with a friend. Once you both learn Morse Code, you can communicate with each other with a flashlight. Do not try to remember the letters as they are sent to you; instead, use a piece of paper and a pencil to write down the letters as you receive them. That way you can concentrate on one letter at a time and not worry that you will forget those letters that were already sent to you.

Letter Code

A . -

B - . . .

C - . - .

D - . .

E .

F . . - .

G - - .

H . . . .

I . .

J . - - -

K - . -

L . - . .

M - -

N - .

O - - -

P . - - .

Q - - . -

R . - .

S . . .

T -

U . . -

V . . . -

W . - -

X - . . -

Y - . - -

Z - - . .

 

Digit Code

0 - - - - -

1 . - - - -

2 . . - - -

3 . . . - -

4 . . . . -

5 . . . . .

6 - . . . .

7 - - . . .

8 - - - . .

9 - - - - .

Period . - . - . -

Comma - - . . - -

Question mark . . - - . .

Apostrophe . - - - - .

Hyphen - . . . . -

 

Suggestions for Teachers:

Divide the class into small groups (two to five students) for practice. Have one student at a time in each group code a word and flash it on the wall or the side of a board or notebook that is propped up. The other students in the group should try to decode the word. Allow them to use the printed code sheet until they know the code. Make sure all students get practice at both sending and receiving messages. When they get proficient at decoding words they should code sentences, and eventually whole messages.

Carolyn Nixon, Center for Economic Entomology

Charlie Warwick, editor



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