Have you ever wondered which one end of an earthworm is more sensitive to odours. Let’s find out.
Things Required:
Earthworms (purchase at a bait shop or dig up your own)
Paper towel
Cotton balls
Fingernail polish remover
Directions:
Place several worms on a paper towel moistened with water. Wet the cotton ball with fingernail polish-remover. Hold the wet cotton ball near, but not touching the front or head end of the worm. This will be the end closest to the wide band around the worm’s body. How does the worm respond to the odour?
Hold the wet cotton near, but not touching, the tail end of the worm. Is there any difference in the response? Try holding the wet cotton near, but not touching other sections of the worm’s body.
This Is What Happens:
The worm shows no area of greater sensitivity to the odour on the cotton ball. The worm makes an effort to move away from the irritating smell no matter where the cotton is placed.
Science Behind It:
An earthworm does not have obvious sense organs, such as a nose, but it does have a nervous system that responds to stimuli such as odours. It has a brain at the front end of the body with a large nerve cord extending all the way to the tail. Each body segment also has a mass of nerve tissue that controls activities within the segment. This is why the worm responds to odour at any place on its body.
