This is such a great water color lesson to do at the end of the school year. I did it with second graders, and they loved it. I was actually at the beach this past week and saw several jelly fish and thought about this lesson and had to come home and blog about it.
This lesson can be done in a 40 minute class.
I borrowed this lesson from http://www.deepsparkle.com/. She actually has a video you can watch of the lesson.
Materials:
Water color, we used liquid watercolor
Jars of water
meduim to small brushes
White heavy drawing paper
oil pastels
I began the lesson talking about jelly fish and their shape. I actually drew this on the board. Curved at the top and wavy at the bottom. The inside of this shape was to be painted with lots of water color, puddles inside. Then they were to hold the paper up and watch the paint drip down to the bottom. Note: have something underneath to catch the water color. Some times it took at bit of tapping of the paper to make the watercolor run.
Student were asked to paint 4 or 5 jelly fish on their paper. I demonstrated how to stagger the fish to fit all on the paper.
Next: after all fish are on the paper using a small fish paint more tenticles down to the bottom of the paper to make the drips that were made. It is fine if the paint mixes a little. This adds creativity. See below
Next BUBBLES. Dip brush is water color, wip and tap, tap , tap specks on the paper. travel around the paper with these. Use different colors. 
For the final step wait a couple of minutes for paint to dry. Using oil pastels draw more tenticles lightly. If the jelly fish is green use a green pastel. See below
