Differentiating Scientific Classification SC020108

Unit 1: Properties of Materials and Mixtures

Lesson 8: Edible Mixtures

Big Ideas of the Lesson

·  When mixing ingredients for cooking, some of the solids will dissolve and some will not.

·  If the component parts can no longer be separated, it is no longer a mixture.

Abstract

In this lesson children recall the definition of mixture while making brownies. They hypothesize how to separate components from the mixtures in the brownies and in ice cream.

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).

·  recognize that when a science investigation is done the way it was done before, similar results are expected (S.RS.02.13).

·  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

Brownie mix with nuts and package ingredients

Baking pan

Ice cream (Rocky Road)

Ice cream scoop

Large spoon

Measuring cups

Mixing bowl

Napkins

Oven

Paper plates and bowls

Plastic spoons

Student Resource

Gabrys, Jennifer, and Claudia B. Douglass. Supplemental Materials (SC02010801.doc). Teacher-made material. Waterford, MI: Oakland Schools, 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 brownies and purchase Rocky Road ice cream. Arrange for additional adult help.

Safety Precaution: There are nuts in the brownies and also in the ice cream. Be aware of allergies. You may want to emphasize that while this is an activity that can teach science, it is not an experiment, so the “no tasting” rule will not apply. Do not use any equipment that was also used for experiments.

1.  Tell the children that today you are going to review mixtures and think of a few new ways to separate the component parts of a mixture.

2.  Bring out the brownie mix. Ask the children to add the ingredients and to decide if it is still a mixture. When you add the mix to water, ask: “Will it dissolve?” [Yes, to a great extent. Some of the mix is sugar, which dissolves. Some is flour (starch), which will dissolve somewhat in warm water but very little in cold water. The chocolate is very oily, and does not really dissolve.] Add the egg. Ask if it is a solid or a liquid. [Eggs are mostly liquids, oils and proteins dissolved in water. The membranes are solids.] Add a few solid items near the end (nuts, chips, etc.) Ask how these items could be separated from the batter. [By using a spoon or by sucking off the batter from the chips or nuts.] Bake the brownies.

3.  While the brownies are baking, show the children some Rocky Road ice cream. Note that there are several things in the ice cream. Ask how they might be separated. Allow the children to make several suggestions. Do not bring the discussion to closure, just wait until snack time and discuss this again.

4.  On the Student Page show children the recipe for brownies. Have them circle the L (for liquid) or the S (for solid) for each ingredient.

5.  Serve each child a brownie and scoop of ice cream. Challenge them to separate what parts they can. Ask them if they let the ice cream melt, would they be able to more easily find the nuts and chocolate chunks. [Yes. Ice cream is actually an emulsion of cream in ice and water, with dissolved sugar and suspended chunks of other things. An emulsion is a dispersed mixture of one liquid in another, such as fat in water.]

Assessment

Listen to the children’s contributions to the discussion and notice if they understand the concept of a mixture.


Application Beyond School

At home, the children can observe things that are mixtures and things that are not.

Connections

Health and Physical Education

While learning about mixtures, children can explore the types of foods that involve mixtures.

The Oakland Schools Curriculum Page 1 of 3

scope.oakland.k12.mi.us June 24, 2009