We all know how much kids love to get their hands messy, so why not try out the incredibly entertaining and easy Oobleck sensory activity? Oobleck is cool because it acts both as a liquid and a solid. You can pick it up in a handful like a solid, but then watch as it drips through your fingers like a liquid.
The name for this silly substance comes from the Dr. Seuss 1949 book Bartholomew and the Oobleck in which a gooey, green substance falls from the sky, wreaking havoc on the kingdom. Reading the book to your kids before doing this activity is a great way to introduce it and get them even more excited!
So here’s what you do to make your own Oobleck:
Mix together two parts cornstarch with one part water.
No really, that’s all it takes to entertain your child for hours! To spice it up, you can add a few other things, but I’ll get to those later. I don’t actually measure when I make it; I just mix the cornstarch and water a little at a time until we get a consistency we like. For thicker Oobleck that doesn’t melt away to a liquid as quickly, use less water. Before I combine the ingredients, I always add a few drops of food coloring to the water, since my 2 year old has been really excited about the color blue lately.
Here are a few ways to spice up your Oobleck, if you choose:
- My daughter absolutely loved the Oobleck by itself, but when we combined it with her other favorite thing in the world—bubbles—she about lost it! Start with combining the cornstarch with blue Dawn dish soap. This will create a thick, dough type substance. If you leave that long enough, it will slowly liquefy, but it’s fun to squish and stretch the dough as well. Then, you can add water and the Oobleck will bubble!
- If you want to make Glow in the Dark Oobleck, try adding Glow Water to the cornstarch. Glow water is just cutting open a nontoxic yellow highlighter and pouring out it’s yellow into water. Some highlighters have a spongy part inside them that, once cut or rinsed under water, will expel more of the yellow liquid. While your Oobleck won’t look like much under normal light, it will instantly glow under a black light, so you’ll need one of those! The highlighter liquid is safe to the touch as long as you make sure you use nontoxic ones.
- For “girlie” Oobleck, you can add plenty of glitter and a few drops of pink food coloring into the water before combining with cornstarch.
To really make this activity a learning experience, be sure to talk through each step and make observations with your children. As you begin, you can point out the different properties of each ingredient you will use before you mix it, such as how smooth the cornstarch powder feels, how wet the water is, etc. Then after mixing, discuss how hard the Oobleck feels as you squeeze the mixture in your hands before letting is drip between your fingers like water. Have your child hypothesize why they think the substance acts the way it does, and use the vocabulary words pressure to explain why the Oobleck’s viscosity (thickness) changes. (If you really want to get deep, compare this to other substances that change their states when temperature is applied, instead of pressure, such as water to ice.) Applying force when squeezing or tapping the Oobleck makes the substance thicken, which is why it seems to become solid for a few moments.
Tips for mess and clean up:
- For a less messy way of combining the ingredients, you can pour the cornstarch and water, along with food coloring drops, into a plastic baggie and seal it. Then mix the ingredients by massaging the bag. It’s way more fun for your kids to get to stick their hands (and even feet) directly into the Oobleck, but if you’d like to reduce mess, only allow them to play with the substance through squishing the bag.
- If any Oobleck drips onto your floor, you don’t have to try to scrub it up right away. Leave it for a day or two to allow the water to evaporate, then just vacuum up the remaining cornstarch. Though it may be a good idea to lay down a plastic trash bag first, if you’re worried about drips. One thing I didn’t prepare well enough for was to cover the cracks in my floor. The Oobleck we spilled wiped up easily, except from between the cracks in the floorboards. Or, if the weather is nice, do this outside and you won’t have to worry about that!
- When you’re finished playing, clean up and disposal is easy. You can either leave the Oobleck out for the rest of the day for it to dry out, then scrape it out into the trash, OR you can add plenty of extra water to the mixture so its very liquidy and pour it down the drain. If you want to wash it down the sink, it’s important to dilute it a lot first because you don’t want to accidently clog up your pipes! Washing your hands with warm water and soap will take off any Oobleck left over.
To end the activity, head to YouTube to find a clip from the Ellen DeGeneres show in which Steve Spangler shows Ellen a huge vat of Oobleck and has an audience member run across it, as if walking on water. How fun would that be??
Have you ever made Oobleck before? What’s your favorite way to play with it? Leave us a comment below!