Thursday, July 7, 2011

Octavia and the Purple Ink Cloud

Today we read this cute story about an octopus who just can't get her ink cloud right.  It is a great story to enforce color recognition and to keep trying.
We made a Cartesian diver to represent Octavia.  The pics are kind of hard to see I think because they reflect off the water.  When you put a little colored water in the diver it will spit out an ink cloud just like Octavia.

How to make a Cartesian diver.  Preparation takes  a lot of adult preparation, but the kids love squeezing the bottle to see the ink cloud. (good for the muscles)
You need a plastic pipet.
I've gotten them in art and education stores in the science section. 
(I will give you some links for using a straw and an eye dropper)

Cut the end off and put a nut on the end to weigh it down.
Now is when you may want to decorate it like an octopus.  Use waterproof materials and make sure you don't cover up the hole.  We used electrical tape, string, and tried permanent markers, but they weren't so permanent.

In a cup make enough colored water to cover the pipet.
Here is where you have to do some timely experimentation.  Squeeze enough water into the pipet to make it barely float.  Just the very tip should stick out of water.  Try letting water out one bubble at a time.  If it sinks you have to squeeze some water out.
Put it into a bottle of water.  Seal it tight but don't glue it.  You will have to take it out and redo it after a while.

When you squeeze the bottle, the octopus will dive down the bottle.
When you let go, ink will squirt out.
We tried putting blue water in the bottle and red in the diver to make it purple when the ink came out but that didn't work.  So I would stick to just putting purple in the pipet.  I have found that 2 liter bottles are too hard for little hands to squeeze.  This water bottle was perfect for squeezing but makes it hard to see because of the bumps.  I would suggest trying to find a small smooth bottle 
Here will show both how to use a straw and medicine dropper.


  1. I am going to have to try this so I can see how it works. I will have to find the book too!