Grade level(s):Elementary School (K-5), Grade 4, Grade 5
Subjects(s):Chemistry, Physical Science, Science Skills
Topic:States of matter
solid, liquid, property,
What you need:
- lots of newspaper to protect tables
- roll of masking tape
- 4 boxes of 16oz cornstarch
- measuring cups (one set per group if students prepare their own Oobleck)
- mixing bowl (one large one if teacher prepares Oobleck, several small ones if students prepare Oobleck themselves)
- green foodcoloring
- popsicle sticks
- paper towels
- different shaped containers
- Rock or piece of chalk
Students can work in groups of 3-4 students
- Reading part 1 of "Bartholomew and Oobleck": ~ 10min
- Making and exploring Oobleck (including discussions & reflection): ~45min
- Clean-up: ~10min
- Writing ending to "Bartholomew and Oobleck": ~30min
- Sharing samples of students writing: ~15min
Students will read the first part of the book by Dr. Seuss, "Bartholomew and the Oobleck," where they learn about the mysterious substance "Oobleck", created by a group of magicians in the story. Students then make Oobleck from cornstarch and water and observe its properties, realizing that Oobleck does not behave like other solids or liquids. After experiencing Oobleck first hand, students create their own ending to "Bartholomew and the Oobleck".
Students will be able to characterize matter as solid or liquid and name examples of each.
Students practice their creative writing skills.
Oobleck is what scientists call a “Non-Newtonian” liquid. Sir Issac Newton stated individual liquids flow at consistent, predictable rates. Oobleck does NOT follow those rules. It acts like a liquid when being poured, but like a solid when a force is acting on it. You can grab it and then it will ooze out of your hands. Technically speaking, Oobleck is a SUSPENSION, meaning that the grains of starch are not dissolved, they are just suspended and spread out in the water. If you let Oobleck sit for an while, the cornstarch would settle to the bottom of the bowl.
So why does this concoction act the way it does? Most of it has to do with pressure. The size, shape, and makeup of the cornstarch grains causes the cornstarch to “lock-up” and hold its shape when pressure is applied to it. People have filled small pools with oobleck and they are able to walk across the surface of it (as long as they move quickly.) As soon as they stop walking, they begin to sink.
You can choose between making the Oobleck yourself ahead of time or having the students mix there own. Instructions for both are below.
Making the Oobleck ahead of time
It can be a good idea to prepare the Oobleck about one hour before the lesson to allow time to make adjustements to ensure right consistency:
- In a large mixing bowl, mix 4 1/2 cups (1 liter) of water with 15 drops of green food coloring.
- Start adding the 4 boxes of cornstarch slowly to the water. You can start using a spoon, but will need to switch to mixing the mixture with your hands soon.
- Depending on the brand of cornstarch you will need more or less than 4 boxes. Play around with adding cornstarch or/and additional water until the consistency is just right. The goal is to get a consistency where the Oobleck reaches a state that is the liquid and yet solid. It should flow if you tip the bowl, but feel like a solid when you hit it or rub your finger across the surface.
It is better to err slightly on the souply side since some water will evaporate in the time between making it and handing it out to the students.
- Shortly before the start of the class, pour about 1 1/2 cups of Oobleck into bowls for each team.
Students mixing their own Oobleck
If students make their own Oobleck, prepare a material station where students can pick up the materials they need. The easiest is to have everything a team needs set-up on trays. Each team will need:
- 1 cup of water
- 1 1/2 cups of cornstarch
- green food coloring
- small mixing bowl
- paper towels
- popsicle sticks
Prepare work area
Spread several sheets of newspaper on each table and secure with masking tape. If the room has carpet, you want to put newspapers on the floor under the edge of the tables.
Lesson Implementation / Outline
Tell students that they will read a story about a very mysterious substance today. Either read out loud "Bartholomew and the Oobleck" to your students or distribut copies of the book to your students and have them take turns reading out parts of the book. Stop after the line "Run!" barked the King. Bartholomew ran."
Tell students that they now will have a chance to (make and) experience Oobleck themselves.
Explain to your students that their job is to investigate the properties of Oobleck. Use an example (a piece of chalk or a rock work well) to explain what is meant by "properties of a substance" and demonstrate the process of recording these properties on the board. Don't spend more than 5 minutes on this.
Tell students that they will explore Oobleck with all their senses except tasting it and are charged with observing as many properties as possible. Encourage students to touch Oobleck with their fingers to explore its properties.
If students make their own Oobleck, explain how to mix the cornstarch, water and food coloring by reading the instruction sheet to your students and pointing out the different materials and equipment that they will receive on their tray.
***Important: Always give instructions BEFORE handing out materials. Otherwise students will be busy exploring the materials instead of paying attention to your instructions***
Hand out the tray of materials if students are making their own Oobleck or a small bowl of already prepared bowl of Oobleck and popsicles sticks.
Allow about 5-10 minutes for the students to freely explore Oobleck. Walk from group to group and ask guiding questions to help students describe properties they are observing. ("How does Oobleck behave when you press on it?", "Can you pick up a piece of Oobleck?", "Can you roll Oobleck into a ball?" "What happens when you try to bounce the ball of Oobleck?" "Can you poke Oobleck with the popsicle stick?")
Pick one students per group (random or choosen by you) to wash their hands so that they can be the recorder for their team. Tell students that as a team they have to come up with at least 6 different properties of Oobleck which the recorder will write down in his/her science journal. Check in with each group to make sure that all members are contributing to the list of properties.
Once each team has their list of properties, have all students wash their hands and gather on the carpet (or another area away from the Oobleck). Have each team share out one property of Oobleck. Record on board. Continue hearing from groups until no more additional observations are shared.
If students have not mentioned it yet, ask them if they think that Oobleck is a solid or a liquid. Ask them why they think that/ what arguments they have to support their claim.
Show students a cup of water and ask them if water is a solid or a liquid. After you heard from a couple of students (or ask by show of hands), tell students that water is a liquid. Ask them what properties liquids have. Hear from some students.
If students are having difficulties describing properties of a liquid ask guiding questions such as "What happens when I slowly turn over the cup with water inside?" and then demonstrate by pouring the water from one cup to another. Ask "How is this different than a solid?" and then demonstrate pouring a cup with a rock or a block into another cup. Have students describe the difference (Liquids flow - they can be poured. Solids don't flow, they fall out in once piece).
Then pour the water from one container into the next, choosing different shaped containers. Do the same for the cup containing the solid. Again, ask students to describe the difference. (The liquid takes on the shape of the container, the solid holds it's one shape).
Ask if you can pick up a liquid or a solid, then demonstrate. Have students share what they saw. (You can pick up a solid but not a liquid)
Ask if you can poke into a liquid or a solid with a stick, then demonstrate.Have students share what they saw. (You can put a stick into a liquid but not the solid)
After these demonstrations and discussions, ask your students again if they think Oobleck is a solid or a liquid. Hear some thoughts.
Then let students get back to their table groups and explore Oobleck again, specifically trying to figure out how it behaves like a solid and how it behaves like a liquid.
After 5-10 minutes have students return all materials, remove the newspaper from their tables by folding it up so that any Oobleck spillage is contained inside and wash their hands. Do NOT pour any Oobleck down the drain!! It will clock your pipes!
Ask students to respond to the following prompt in their science notebook: "In your opinion, what were the 3 most interesting properties of Oobleck?" "When did Oobleck behave like a liquid and when did it behave like a solid?"
Give students about 10 minutes to respond in writing then have some students share out.
Remind students of the story they read in the beginning of the lesson and ask them what they think would happen if it was raining Oobleck. Explain that they should use what they learned about Oobleck and how it behaves and imagine how this will change life in the kingdom.
Have some students share out their ideas. Then tell students that they now will be able to write their own ending to the story based on what THEY think might happen to a world where it rains Oobleck. Encourage students to include drawings if they like to.