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Main Curriculum Tie:
Background For Teachers:
Intended Learning Outcomes:
Invitation to Learn:
Begin by showing the class the two bags and asking them to predict what will happen when you stick a sharp pencil into each of the bags. Stick the pencil into the bag of ice. Ask: “Why didn't anything leak out?” Next hold the bag of water over a large bowl or bucket and quickly stick the pencil through both sides. No water should leak out. (You should practice this before class.) Ask the class to explain why the water didn't leak out. (The plastic shrank together and sealed the hole around the pencil.)
Make a T-chart or Venn Diagram on the board and have the students list the properties of the ice on one side and the water on the other side. Remind students that weight is a property of matter. Ask: “If I took a bag of water and froze it, would it weigh more before it was frozen of after it was frozen?” Listen to their answers and explain that today they are going to do an experiment to discover the correct answer to that question.
After students have completed the activity allow them to share what they have learned. Discuss the statement: The weight of a specified quantity of water (liquid) is equal to the weight of the same quantity of ice (solid). Is this statement always true? Is freezing a physical change or a chemical reaction? Why? (No new substance is created; the water just goes through a physical change.) Is this statement true for all forms of matter? How would you test other types of matter?
You may wish to allow students to investigate other types of matter. (See Possible Extensions.)
Have each team select a different substance to test and write step-by-step procedures for conducting the experiment. Allow teams to share their data after completing the experiment. Work with each team to ensure that safety concerns are addressed while melting and freezing the substances, and that neat and accurate data is collected.
Use this rubric to assess your students ' performances:
Student 's Name ____________________________________
Created Date :