Experiment with Squid Ink
In this science experiment, kids will explore the squid adaptation that allows them to squirt ink and hide from predators.
A squid releases ink from sacs located between its gills; it then disperses the ink by releasing a jet of water from its siphon. The ink's dark color is caused by its main component, melanin. This ink creates a cloud in the water that the squid can hide behind.
Squids are cephalopods, as are octopuses and cuttlefish. All cephalopods release ink, but each produces a slightly different color: generally, octopuses ink is black, squid ink is more blue-black, and cuttlefish ink is brownish.
Print out a squid or octopus picture from the internet and cut out. The picture should be small enough to fit on one side of a clear cup.
Tape the picture on the outside of the cup, with the picture facing in so that you can see the squid through the cup.
Fill the cup with water and observe the squid through the water. How does it look?
Now add two drops of the black paint and swirl. Observe the squid now. Is it harder to see? Add two more drops. How does this change how well you can see the squid?