States of Matter
- 1¼ cups of cornstarch
- ½ to ¾ cup of water
- Paper towels
- Hand wipes
- Measuring cups
- 3 bowls, large
For the proper making of Oobleck:
- Mix the cornstarch and water in a large bowl
- Mix it with your hands for the right consistency (add water or cornstarch as needed to get the right consistency)
- Place the 3 bowls out for people to see
- Use the cleaning supplies to clean the area and hands
What variables are important in this activity? How could you design an experiment to test whether the variables are important or not?
What happens when you apply quick bursts of force on the oobleck?
What happens when you allow the oobleck to settle?
Is Oobleck a liquid or a solid?
Pressure is the ability to apply force to an area and have the force be distributed. Oobleck is such a great experiment for kids because it demonstrates how when force is applied it increases its viscosity. This explains to students how an object can be either liquid or solid depending on its state of matter. There are three different activities that will display the liquid and solid phase of the oobleck to the students. This activity consists of students playing with the oobleck and punching it realizing that with a great force it turns to solid. However, when a student touches it slowly it turns to liquid. Oobleck is a great way to show students how objects can be in different phases; solid, liquid or gas!
Ask the kids to try and touch the oobleck ask them what they feel. Then, tell them to move their hand around the bowl, smoothly and slowly. The mixture acts a liquid. It is easier to move your hand. Next, ask them to try and move their hand really fast or to try poking the bottom of the bowl. Again they will be able to see that it is harder to move around because the mixture is acting as a solid. It can be described as being, heavier, thicker and so on. Explain that this happened due to the fact that, the more force you place on the mixture determines how solid the Oobleck will turn; and how if you actually move slowly, you have a better chance of getting out easily. It is determined that if you lie on your back, like you were in a pool, you would be able to float to the top. This is because our bodies are less dense than the actual Oobleck. This is a surprising fact.
- Grades K-3
A liquid is something that takes the shape of the container that it’s placed in. Some examples of liquids are water, juice or milk. The oobleck is liquid when you gently touch it. A solid is something that can hold its shape. Some examples of solids are a table, a jacket, or a shoe. After hitting the oobleck it becomes a solid. Why? When you push on something it’s called applying pressure. When pressure is applied or when you push on something hard enough, it can change the way it acts, like when playing freeze tag. When you play freeze tag you run around like a liquid and when someone tags/touches/pushes you, you freeze, like a solid, you don’t move. When you hear a sound, there are invisible waves floating through the air that reach your ear so you can hear. You can’t normally see them, but you can see them with the oobleck on the speaker. An example of waves are like the waves at the ocean. Can you make a wave with your hands?
- Grades 4-6
A liquid is something that takes the shape of the container that it’s placed in. Some examples of liquids are water, juice or milk. If milk is poured onto the table it would go everywhere and make a mess. The oobleck is liquid when you gently touch it. A solid is something that can hold its shape. Some examples of solids are a table, a cell phone, or a tablet. If a cell phone is placed on a table it’s not going to move. After hitting or speed walking on the oobleck it becomes a solid. Why? When pressure is applied, it can change the way it acts. When you hear a sound, there are invisible waves floating through the air that reach your ear so you can hear. These waves have both a frequency (how quickly they rise and fall) and an amplitude (how high the waves go up). You have probably seen this effect at the beach. You can’t normally see waves of sound, but you can see them with the oobleck on the speaker.
- Middle School
In a liquid, molecules are very spaced out and move around. In a solid, molecules are very close together and don’t move due to intermolecular forces. When you hold hands (intermolecular force) with someone (solid) it is more difficult to move around then when you are by yourself (liquid). When pressure is applied to the oobleck, it’s like forcing the molecules to hold hands, causing it to act like a solid. Different songs make the oobleck dance and move differently. This is due to the different wavelengths and frequencies of the music playing.
- College Level
Pressure is the ability to apply force to an area and have the force be distributed. When force is applied it increases its thickness and stickiness due to internal friction, also known as viscosity. An object can be either liquid or solid depending on its conditions, such as temperature and pressure, and the properties of the substance, such as melting point and boiling point. When playing with the oobleck and punching it, realize that with a great force it turns to solid, but when the oobleck is touched slowly it turns to liquid. Different frequencies of sound have different energies. Oobleck over a speaker while playing a heavy metal song displays different frequencies and their effect on the oobleck. With some frequencies, the energy causes the oobleck to be more of a solid as a result of the forces on the oobleck. Speed walking on the oobleck will apply the right amount of force to change the oobleck to a solid while walking slowly across the oobleck allows the oobleck to have the consistency of quicksand.
Next Generation Science Standards
- Science of Motion and Stability: Forces Interactions
- Science of Waves and their Applications for Information Transfer
- Matter and its Interactions
- Science of Waves and their Applications