Background Information: Matter
Managing Time & Students
Related Web Sites
The Dirtmeister is your personal guide to hands-on science exploration in the
classroom. By participating in Dirtmeister's Science Labs, kids have the opportunity to
experience science firsthand. The steps in completing the challenge follow the same
methodology used by scientists in solving problems. After reading the question, students
are encouraged to formulate hypotheses. With science expert Steve Tomecek (the "Dirtmeister") serving
as facilitator, students complete the hands-on investigation and check their results against their predictions.
Teachers who participate in the challenge also have the opportunity to gain valuable experience in teaching inquiry-based science because each new challenge helps reinforce basic science concepts. For personal advice and support from Steve, join the Hands-On Science discussion in the Teacher Center.
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Background Information on Matter
This month, we explore physical changes in matter by mixing up a unique compound called a colloidal suspension. Known as "goop," "glop," or "ooblek," this material is special because it can change its state with a simple touch or a squeeze. When it sits in the bowl, the matter is clearly in a liquid state. It can pour, take the shape of the container it's in, and flow from one place to another. The second you put this material under pressure, however, it changes state to become a rigid solid. In this particular case, the energy to cause the change is mechanical instead of heat. When the pressure is released, it goes back to a liquid state.
Colloidal suspensions belong to a special class of liquids called "non-Newtonian." A Newtonian fluid is like water. It flows easily from one place to another. When you subject it to pressure, it simply flows out of the way. In a non-Newtonian fluid, the exact opposite happens. When you "shock" it, it suddenly turns solid. The reason for this strange behavior is that it's really two states of matter in one! When you mix the corn starch with the water, the corn starch does not dissolve. Instead, the little particles of starch get suspended in the water and float making it a very thick liquid. When you put sudden pressure on the suspension, most of the water runs out from between the grains leaving the solid corn starch particles to lock up tight. As soon as the pressure is released, the water flows back between the grains, making the mass fluid again.
Colloidal suspensions don't just happen in a lab. You can find them in your kitchen in a ketchup bottle. When people don't want to wait for the ketchup to come out, they usually try hitting the bottom of the bottle. This is the wrong approach because shocking the bottle makes the ketchup turn solid. Instead, simply turn the bottle over and stick a knife inside. The knife blade will give the ketchup a surface to flow along. As long as you don't shake it too hard, it will stay a liquid!
Note: When you are done experimenting with the mystery matter, don't dump it in the sink! Let it dry to a solid and then put it in the garbage.
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Learning Outcomes/National Standards Correlations
This Dirtmeister's Science Lab on ecosystems helps students meet the following science-content standards as set forth by the National Research Council of the National Academy of Sciences:
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- Students conduct a simple investigation. (Content Standard A)
- Materials can exist in different states - solid, liquid, and gas. Some common materials can be changed from one state to another. (Content Standard B)
- A substance has characteristic properties. (Content Standard B)
Managing Time and Students
Classroom management is always a critical factor for any successful lesson, and the Dirtmeister's Science Lab is no exception. The following strategies will help to maximize the use of the activity in various classroom situations:
The activity can be used as a class demonstration integrated into a larger unit dealing with physical changes in matter. In this case, all students can make predictions while one or two volunteers can carry out the activity in front of the room.
For a more hands-on discovery approach, it is recommended that students work in groups of 3-4, sharing their predictions and observations. With the entire class working in teams, the hands-on portion of the challenge will take approximately 30 minutes to complete.
While younger students (grades 12) should have no problem working with the matter, things may get a little too messy. In this case, you might want to have one big bowl of mystery matter that you can bring around the room and have each student touch and observe.
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Here are some suggestions to enhance the experience of Dirtmeister's Science Lab for your students:
Extensions on Matter
- Have the class make a list of all the different substances that they can think of that behave like the mystery matter. Ketchup, quicksand, and even chocolate milk are all suspensions. See how some of these others compare with the mystery matter in different test situations.
- One of the biggest problems with volcanoes is the sudden mud slides that occur after a prolonged rain. Volcanic ash mixed with water is a colloidal suspension, just like "mystery matter." Have the students use the mystery matter mixture to make a model landscape and have them try to engineer a way to keep a landslide from happening. Ask them to test their ideas by building different types of structures with Popsicle sticks, blocks, or Legos.
- For younger students, read a copy of Bartholomew and the Ooblek by Dr. Suess. Then compare Bartholomew's problem with the mystery matter in the bowls. You might want to add some green food coloring to the mystery matter to make it match the material in the story!
- Talk to your school librarian about the best ways and places to research exotic forms of matter in the library, using books and multimedia resources. (See Section 8 below.)
- Have the class use the computer to search the Web for supplementary articles on physical and chemical changes in matter and the uses of new engineered substances in such fields as construction, biotechnology, and electronics.
- Provide space on a classroom bulletin board for the Dirtmeister's Science Lab. Assign different teams of students the task of designing the board and changing the postings to reflect the different Science Lab topics throughout the year.
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- Using computer software such as ClarisWorks or Microsoft Works, have students create and maintain electronic science journals. Encourage students to illustrate their work by using drawing or painting features of the software. This is an excellent way to keep notes and store the labs for future use.
- Have each student write an article about their favorite science experiment. Compile the articles into a science newsletter. If your class already publishes a monthly newsletter, feature a science topic in each issue, rotating the responsibility of writing the articles throughout the class.
The following Scholastic supplemental materials can be used in conjunction with Dirtmeister's Science Lab.
Big Books: Science (Grades K-4). This book series covers a variety of topics, from bugs to wind. They are brightly
illustrated and great for the classroom library.
Environmental Atlas of the United States, by Mark Mattson (Grade Levels 4 and up). The only environmental atlas for young
readers that emphasizes U.S. ecological information.
Be a Scientist skills books (Grades 3-6). This series includes featured scientists, hands-on activities, and an emphasis on
practical process skills. The series consists of three sets of three books each for grades 3-4, 4-5, and 5-6.
Super Science (Grades 3-6). High-interest articles and hands-on activities teach
basic science and technology concepts. Each theme-based issue presents timely news and
stimulates students' interest through fun activities. Exercises develop critical-thinking skills
and help you meet the National Science Education Standards.
Quick and Easy Learning Centers: Science, by Lynne Kepler (Grades 1-3). This Professional Resource book focuses on the
use of everyday materials to promote independent, hands-on learning. Information on how-tos, management, experiments,
and reproducibles are included in this helpful book.
Call Scholastic directly at 1-800-724-6527 to order and for more information.
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Related Web Sites
General Science Sites
Science and Technology for Children Curriculum
The Natural History Museum (London)
Understanding Our Planet Through Chemistry
Edison National Historic Site
Endangered Species Program
National Inventors Hall of Fame
Maps and References
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