Oobleck is a substance that has interesting physical properties and is easy to make. It is in fact an example of a non-Newtonian fluid. Many commonly used liquids, such as water and alcohol, have a constant viscosity, but the oobleck can be fluid when you hold it without squeezing it, and then react like a solid if hit hard. The substance owes its name to Dr. Seuss's children's book "Bartholomew and the Oobleck" written in 1949 about a child so bored with the climate that he rages in his kingdom that he wishes something completely new would fall from the sky.
Steps
Part 1 of 2: Preparation
Step 1. Put 140g of cornstarch in a large bowl
You can take a minute to mix the ingredient with your hands to get used to its texture. It is worth working it briefly with a fork to get rid of any lumps; this will make it easier to mix it up later.
Step 2. If you have decided to color the oobleck, add 4-5 drops of food coloring
While this is not an essential step, many prefer to color the substance to make it fun and much more exciting than a white batter. If you've opted for a colored oobleck, mix the dye drop by drop in the water before incorporating it into the starch. In this way, the tint is distributed evenly.
Add as many drops as you like until you get the color intensity you prefer
Step 3. Add 120ml of water to the starch
You should always maintain a volume (not weight) ratio of 1: 2 between water and starch; for every cup of water you should therefore use two of cornstarch. You can use your hands or a spoon to best incorporate the two ingredients.
Step 4. Test the oobleck by taking a handful and trying to shape it into a ball
The difficult thing about this preparation is finding the right proportions. It is rare to be able to mix exactly two parts of starch with one part of water on the first try. Humidity, the amount of food coloring and the temperature of the water are factors that affect and bring about small changes. You should have the feeling that the oobleck is melting in your hands.
- If you can't make the mixture into a ball because it's too liquid, add more starch, one tablespoon at a time. Stir and repeat the test with each addition.
- If when you lift it it doesn't flow like a liquid, the oobleck is too thick. Pour in more water, one tablespoon at a time.
Part 2 of 2: Usage
Step 1. Play with the compound
At first remove it from the bowl with your hands and have fun kneading it, hitting it, molding it into a ball, letting it drip into the bowl and giving it various shapes. You can also:
- Mix and match it with other colors to create designs;
- Put it in a colander, in a basket for strawberries and so on to let it drip, observing how it flows differently than water.
Step 2. Do some experiments
As you become more comfortable with the substance, you can see what happens when you squeeze it firmly in one hand or when you let it rest for a moment before lifting it again. Here are other experiments you can do with the compound:
- Create a ball of oobleck by rolling it quickly between your palms. Then stop the pressure and let it flow from your hands.
- Fill a cake pan with a thick layer of oobleck and poke the oobleck with your open hand. You will be surprised that all the liquid will remain in the container, despite the force you exerted.
- Do the cake pan experiment again but big: now fill a bucket or plastic basket with the substance and jump on it with both feet.
- Put the mixture in the freezer and try the experiment again. Give it another try but with the hot oobleck. Did you notice any difference?
Step 3. Clean
You can use hot water to get the mixture out of your hands, clothes and even the kitchen counter. You can rinse the bowl a little, but make sure that most of the material doesn't fall down the sink drain.
If you let it dry, the oobleck will turn to dust and you won't have a hard time removing it with a broom, vacuum cleaner or cloth
Step 4. Keep it
Put it in an airtight container or zip lock bag. Take it off again when you want to have fun and play with it. If you have decided not to use it anymore, Not throw it down the sink drain as it could clog it. Throw it in the trash.
In order to play a second time you will need to add more water
Advice
- It's fun to try and shape the oobleck into a ball. If you give it a try, you will find that it becomes solid, but that it melts in your hands as soon as you stop moving.
- Once dry, you can easily pick it up with a vacuum cleaner.
- It's fun to play with the oobleck! Use it at birthday parties, kids will love it!
- To throw it away, mix it with plenty of water until it becomes quite fluid. Then, pour it in small amounts down the drain while running the hot water.
- It is worth putting some newspaper on the work surface in case the substance falls on the table.
- Keep it in an airtight container and mix it from time to time.
- By preparing this substance, you can entertain children on rainy days, especially just before bathing them.
- If you have decided to add food coloring, you may find that your hands are still a little colored after washing them. Don't worry, the tint should disappear in a day or two.
- If you don't have cornstarch, you can use Johnson & Johnson® Baby Powder.
- Anything that falls into the mixture (such as small toy dinosaurs) can be washed with soap and water.
- If you add the food coloring, the oobleck will create a lot more confusion and the project will have a greater scenic effect!
- A drop or two of clove oil prevents the proliferation of microbes.
Warnings
- Remember that if you leave the oobleck in the air for too long, it will dry out and become plain cornstarch again. When you're done playing, throw it away.
- Don't worry if the substance gets dirty on any surface, you can clean it with a little water.
- The oobleck is not poisonous, but it has an unpleasant taste. Wash your hands after playing and keep an eye on the children.
- Do not pour the oobleck down the drains as you could clog them.
- Put on some old clothes, you will get a little dirty.
- Cover the floor and the table with the sheets of some newspapers, so as not to dirty them with the product.
- Do not let the substance drip onto the sofa, desk or driveway, as it is not easy to remove it from these surfaces.
