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M&M's in Different Temperatures

Does the temperature of the water affect how fast the colored coating dissolves from an M&M

In this activity, students will discuss variables and ways to control them as they design an experiment to investigate the question. When they conduct their experiments, students will discover that the color moves somewhat faster in hot water than in room-temperature water and much faster in hot than in cold. Since the temperature of water is the only difference between the plates, students can conclude that temperature does make a difference in how fast the colored coating dissolves from an M&M.

Materials needed for each group

  • 3 Same-color M&M's
  • 3 White plastic or foam dessert plates
  • Room-temperature water
  • Hot tap water
  • Cold water
  • Round film canister lid or a quarter
  • 1 Plastic Cup
  • Crayons or colored pencils
  • Permanent marker
  • Bucket or large bowl
  • Paper Towels

Notes about the materials

Be sure you and the students wear properly fitting goggles.

Students should use care when handling hot tap water.

Preparing materials

  • This activity uses cold, room-temperature, and hot water. For best results use ice water, water that is about 20°C, and water that is about 45°C.
  • You may wish to draw concentric circles in the center of plates ahead of time. Or students can draw them as part of the activity. The procedure for drawing these is described in Activity 1.2: Racing M&M Colors.

Activity sheet

Download the student activity sheet, and distribute one per student when specified in the activity.


An assessment rubric for evaluating student progress during this activity is via download on this page. For this formative assessment, check a box beside each aspect of the activity to indicate the level of student progress. Evaluate overall progress for the activity by circling either “Good”, “Satisfactory”, or “Needs Improvement”.

Question to investigate: Does the temperature of the water affect how fast the colored coating dissolves from an M&M?

  1. Have groups suggest experimental designs.

    Have students form small groups and discuss how they might investigate the question and record an initial plan on Activity sheet 1.5—M&M colors in different temperatures. Students should also think about and list the variables that need to be controlled in this experiment.

    As you visit the groups and listen to their discussions, check to see if students are thinking about variables: the kind of plate, the amount of water in each plate, the color of the M&M’s, and the placement of the M&M’s at the same time in each plate. All these variables should be kept the same. Students should realize that the only variable that should be changed is the temperature of the water.

  2. As a whole class, finalize the experimental design.

    Have students share their plans with the whole class. Discuss the students’ list of variables and ask them how their plans control these variables.

    Some groups may have planned to test M&M’s in hot and cold water but didn’t consider using room-temperature water, too. Encourage all groups to test an M&M in all three temperatures of water. The room-temperature water serves as a control and can help students see the difference in how much cold and hot water affects the movement of M&M color.

    Tell students that they will use plates with concentric circles to help compare the amount the color spreads in each plate.

  3. Have groups conduct the experiment.

    Your class procedure will probably be similar to the following.

    1. Use small pieces of paper to label each of three plates cold, room-temp, and hot.
    2. Pour cold, room-temperature, and hot water into their labeled plates so that the water covers the bottom of the entire plate.
    3. With the help of your partners, place a same-colored M&M in the center of each plate. Observe for 1 minute.
    4. Record your observations on the activity sheet.
  4. Have students share their observations.

    Ask students whether they noticed a difference in the movement of color in the different temperatures of water.

    Three students add M&Ms to plates filled with water at different temperatures

    Expected results: The sugar and color dissolve and spread out fastest in the hot water and slowest in the cold water. The sugar and color in the room-temperature water dissolve and spread out somewhere between the cold and hot water, but are more similar to the cold than the hot.

  5. Ask students to answer the question to investigate.

    Ask students if, based on their observations, they could answer the question to investigate: Does the temperature of the water affect how fast the colored coating dissolves from an M&M?

    Students may have noticed a greater difference in the circle of color between the hot and the room-temperature water than between the room-temperature and the cold water. You could ask students for a possible explanation for this. Suggest to students that there is probably a greater difference in temperature between the hot and the room-temperature water than between the cold and the room-temperature water.