Why is my oobleck watery?
You added too much water or added it too fast. Fix it by stirring in cornstarch 1 tablespoon at a time until it feels firm when you tap it, but still drips slowly when you lift a spoon.
Why is my oobleck crumbly or powdery?
Not enough water. Add cool water 1 teaspoon at a time and mix well. It should hold shape when squeezed, then relax back into a puddle.
Can I use flour instead of cornstarch?
Cornstarch works best for classic oobleck behavior. Flour can thicken, but it will not give you the same punchy non-Newtonian effect and it can get sticky.
Is oobleck safe for kids?
It is generally safe for supervised play with basic ingredients (cornstarch and water), but it is not food. For toddlers or kids who still mouth everything, keep it up high or choose edible sensory options instead.
How do I make it feel smoother?
Use cool water, add it slowly, and stop when it stirs smoothly and looks glossy. It should feel soft when you stir, then firm up when you tap or squeeze it. If it feels paste-like, you likely added a bit too much water or it has been handled a lot. Add a spoonful of cornstarch to bring it back.
Can I color it?
Yes. Mix food coloring into the water first, then add the colored water gradually. Start small because a little color spreads fast in a white base. Colored oobleck can stain porous surfaces, so use a tray and skip carpets.