Learning about Ratios: A Sandwich Study

Grade Level(s): 4, 5, 6

Submitted by: Sheryl Weinberg, Southeast Island School District

Overview:

Ratios can be a difficult idea for elementary students to grasp. Spending time manipulating "real" objects provides a tangible reference when later dealing with the concept.. in either an abstract or practical fashion.

Purpose:

The purpose of this activity is to provide students with a concrete introduction to the concept of ratios.

Objectives:

As a result of the activity, students will be able to:

1. Orally define ratio
2. Demonstrate the ability to create ratios with given substances
3. Label ratios
4. Generalize the concept, creating a ratio with a self-selected material

Resources/Materials:

• Chalk
• Peanut Butter and Jelly
• Measuring spoons
• Butter knives
• Paper towels
• Damp sponges
• Teacher developed graphs
• Pencil and Paper

Activities and Procedures:

1. Prior to class beginning, write RATIO in large letters in the center of the chalkboard. State objectives of lesson. Ask students to tell what they think the term means. List student comments on the board.
2. Randomely select 10 students to come forward. Divide the pupils into groups by sex. Have seated learners count the number of boys and girls. Write the numbers above each group, seperated by a colon. Explain that this expression identifies the ratio of boys to girls called forward. Physically structure two additional examples (ex: students by hair color, lunch to milk tickets, pupils that write with pens to those who use pencils.) Label examples. Return to the term on the board and student comments. Have students identify which, if any, ideas identified what a ratio is. Guide pupils in defining the term.
3. Divide class into groups. Direct each group to make a series of six peanut butter and jelly sandwiches, each containing a different ratio of the given spreads. Pupils are to label each ratio. Cut each sandwich into pieces.
4. Conduct a taste test of the preferred ratio. Have each student within a group taste each sandwich and rate it on a scale of one to six.
5. Direct pupils to graph and report the results of the trial individually, and then for the group.
6. Have each group share their charts with the rest of the class. Compare and contrast differences.

Tying it all Together:

1. Direct students to write what they learned about ratios. Ask them to verbally share what they wrote. Encourage students to describe any ratios that they are familiar with.
2. Have students divide themselves into triads or quartets. Explain that each group is expected to identify substances for a ratio study similar to the one conducted with peanut butter and jelly (ex: lemons to sugar to water, red to white paint to create the most desirable shade of pink...) Groups should develop a material list, method of study, and format for presentation of results. Indicate which day students should be prepared to conduct and present their tests.

References:

This lesson was found at Educator's Reference Desk Lesson Plan

Graphic located at UNIVISION.com