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Lesson Plan

 Subject: Math Grade span: 6 to 8 Duration: 30 to 45 minutes
This lesson was excerpted from the Afterschool Training Toolkit under the promising practice: Math Centers

Description:

This sample lesson is one example of how you can implement Math Centers. In this activity, students collect data using large and small marshmallows, much like flipping a coin, to determine the chances of a marshmallow landing on its end or side.

Note:

Adapted from the Connected Mathematics Program. Lappan, G., Fey, J.T., Fitzgerald, W.M., Friel, S.N., and Phillips, E.D. (2002). How Likely Is It? Glenview, IL: Prentice Hall.

Learning Goals:

• Make and test predictions
• Collect and organize data
• Read and interpret data tables
• Use proportional reasoning to solve problems

Materials:

• Several large and small marshmallows for each pair of students
• Ziploc bags
• Pencils or pens
• Molly's Marshmallows (PDF) — a written description for students and the recording chart

Preparation:

• Prepare a plastic bag with several large and small marshmallows for each pair of students.
• Print and copy the Recording Chart from the materials needed section.
• Create an inviting area for students with access to all of the space and tools they need.

What to Do:

• Ask students to pair up in groups of two.
• Review the definition of "data" as pieces of information that students gather to tell the likelihood of something happening.
• Review Molly's Marshmallow Problem with students and make sure they understand their task. Review the question by asking, "What is this problem asking you to do?"
• Ask students to make predictions about whether the two differently sized marshmallows are more likely to land on their sides or ends.
• Encourage students to find ways to work together. For example, one student might flip marshmallows while the other records results.
• As students work together in their centers, move from center to center and ask guiding questions that encourage students to explain their reasoning and work. Try to use new math vocabulary in your interactions. For example, talk about the data, the table for collecting data, and what the data tell (how to interpret the numbers they are recording).
• When students have finished collecting the data from the marshmallow flipping, review the follow-up questions in the problem and how to write fractions from the data (see Tips).
• Ask each pair to present findings, reporting in on initial predictions and whether the answers make sense.
• If time allows, consider converting fractions to percentages.

Teaching Tips:

Understanding Data

Each time students flip a marshmallow and record the result, they are gathering data, information that will help them determine the likelihood of that result happening again.

Interpreting Data and Writing Fractions

Once students have flipped marshmallows and recorded their answers, they are ready to write their answers as fractions and be able to say what percent of the time a given marshmallow will land on its side or end.

For example, one of the follow-up questions asks:

What fraction of the time will a small marshmallow land on its side, according to your experiment?

Sample Answer: If the marshmallow lands on its side 20 times, the answer is 20 out of 50 times. To write that as a fraction, you simply write 20/50. This can also be expressed as 2/5 (two fifths) of the time or 40%. It may be helpful to review converting fractions into decimals with the students, and to explore what the % symbol means and how it relates to decimal and fraction notation.

Evaluate (Outcomes to look for):

• Student participation and engagement
• Prediction-making and testing through experimentation
• An understanding of data, and an ability to interpret the data
• Writing accurate fractions to represent data
• Students using proportional reasoning to solve problems

Standards: