Use as many drops as you want for a richer color.
If you can’t form a ball (too watery), add more cornstarch in one tablespoon at a time. Mix it and test each time. If it isn’t runny like a liquid when picked up, it is too thick. Add more water one tablespoon at a time.
Mix and match with other colors to make designs. Strain and drop the oobleck through strainers, strawberry crates, etc. to watch how it flows differently than water.
Make a ball out of the Oobleck by rolling it around quickly in your palms. Then, stop applying pressure to the mixture and it will flow out of your hands. Fill a pie plate with a thick layer of Oobleck and slap the surface with your open hand. You’ll be surprised by how all of the liquid stays on the plate because of the force you applied. Supersize the pie plate experiment by filling a large bucket or plastic bin with Oobleck and jumping up and down in it. Take the Oobleck in the freezer, and try it. Try it in the heat too. Is there a difference?
If you let it dry out, it turns into a powder that is easily swept, vacuumed, or wiped up.
You’ll likely need to re-add water to your oobleck to play with it a second time.