Differentiating Scientific Classification SC020104
Unit 1: Properties of Materials and Mixtures
Lesson 4: Making Mixtures
Big Ideas of the Lesson
· A mixture is made up of more than one kind of object.
· When a mixture is made, the objects in it do not change.
· Mixtures can be sorted into their original components.
Abstract
In this lesson children are introduced to the definition of a mixture. They make several mixtures and separate them into their original components.
Grade Level Context Expectation(s)
Children will:
· describe objects and substances according to their properties (e.g., color, size, shape, texture, hardness, liquid or solid, sinking or floating) (P.PM.02.12).
· recognize that some objects are composed of a single substance (water, sugar, salt) and others are composed of more than one substance (salt and pepper, mixed dry beans) (P.PM.02.41).
· generate questions based on observations of various objects (S.IP.02.12).
· measure the volume of liquids using common measuring tools (graduated measuring cups, measuring spoons, graduated cylinders, and beakers) (P.PM.02.14).
Key Concept(s)
attribute
material
mixture
property
Instructional Resources
Equipment/Manipulative
Bowls (1 per group)
Container for storing play dough
Cutting board
Fruit and nut mixture (1 oz. per child)
Heat source (hotplate or stove)
Ingredients for play dough (1 ½ cup flour, ¾ cup salt, 3 teaspoons cream of tartar, 1 ½ cup water, 1 ½ tablespoon corn oil, food coloring)
Large spoon
Measuring cups
Plastic cups (1 per child)
Saucepan for play dough
Sealable plastic bags (4 per group)
Variety of dried beans (at least 4 different types)
Student Resource
Gabrys, Jennifer, and Claudia B. Douglass. Supplemental Materials (SC02010401.doc). Teacher-made material. Waterford, MI: Oakland Schools, 2008.
Oxlade, Chris. Mixing and Separating. New York: Crabtree Publishing, 2008.
Teacher Resource
Cole, Joanna. The Magic School Bus Gets Baked in a Cake: A Book about Kitchen Chemistry. Topeka, KS: Econo-Clad Books, 1999.
Texley, Juliana, and Claudia B. Douglass. Second Grade Unit 1 Teacher Background (SC020100TB.doc). Teacher-made material. Waterford, MI: Oakland Schools, 2008.
Sequence of Activities
Advance Preparation: Gather the materials for the snack mix if you are going to make it as a class. Gather the materials for the play dough as well.
1. Give each group of children at least four small bags of different kinds of dried beans. Hold up a sample of each bean one at a time and ask several children to describe it. Have the children draw one bean in each box on their Student Page.
2. Tell the children to pour all of the beans into the dish and mix them together with their hands. Have them draw all of the beans in the large box on their Student Page. They may draw more than one of each bean.
3. Now ask the children to separate the beans, putting them back into their original bags. Again, ask the children to describe the beans. Ask: “Have any of the beans changed as a result of being mixed together?” [No.] “Were you able to sort them all into their original bags?” [Yes.] Have the children draw individual beans in the boxes at the bottom of their Student Page.
4. Explain to the children that a mixture is a combination of objects (substances) that can be separated without changing (without a chemical change). The beans were a mixture when they were combined because there were several kinds of beans together, but they could be separated and remained unchanged.
5. Purchase a fruit and nut mix at the store or make your own as a class (1 c raisins, 1 c peanuts, 1 c small graham cracker bits, 1 c cinnamon cereal). Give some to each child in a small cup. Ask the children to describe what is in the cup. Then allow them to sort their snack into its component parts. Ask: “Can you identify each part?” [Yes.] “Have any of the parts been changed so that they have become something different?” [No.] Ask the children if this meets the definition of a mixture. [Yes.]
6. Make homemade play dough. Note: Ingredients for Play Dough: 1 ½ c flour, ¾ c salt, 3 t cream of tartar, 1 ½ c water, 1 ½ T corn oil, food coloring. Directions: Mix dry ingredients in the pan. Add water and food coloring, and stir. Add corn oil and stir. Cook over moderate heat. Stir until dough pulls away from pan. It will become like instant mashed potatoes. It needs to be quite dry and not sticky. Turn onto a board and knead. It will last several months if used often and stored in an airtight container.
7. Ask the children to measure the ingredients, add them to the pan and stir them. After each addition, ask if they could separate that item from the rest. [For a while one could separate the ingredients. After adding the liquid the individual ingredients can no longer be separated.]
8. When you are finished making the play dough, ask if the children can identify the individual ingredients that went into it? [No.] “Is play dough a mixture?” [No, you cannot get the parts out of it again. Note: There has been a chemical change.]
9. As time permits prepare several other mixtures and put them at a center for the children to separate and mix again and again.
Assessment
Observe the children at the center. Ask how they know whether a combination of objects is a mixture.
Application Beyond School
At dinner, the children can observe what are mixtures and what are not (mixed vegetables and many salads are mixtures; meatloaf and salad dressing are not.) The children can share their experiences with mixtures from home with the class.
Connections
Mathematics
Children can count the items that go into a mixture and then sort and count them again to prove that what they made is a true mixture. The children use measurement skills when working with the ingredients that go into the recipes.
The Oakland Schools Curriculum Page 3 of 3
scope.oakland.k12.mi.us June 24, 2009