Lesson plan developed and implemented by

David Dubois, Amanda Sanniti, Melanie Sleep, Jasmine Sterle-Contala (Chantier7 Project Team Members)

Unit: Mass and Volume

Essential Question: How are mass and volume related?

Big Idea:

• Things that occupy the same volume do not necessarily have the same mass.
• Things with the same mass do not necessarily occupy the same volume.

Prevalent Alternative Conceptions:

• Objects of the same size will have the same mass.
• Students may have some prior knowledge of particles (atoms/molecules), but they may believe that all atoms have equal masses.
• Solids are heavier than liquids, liquids are heavier than gases.
• Solids have volume, liquids and gases do not
• Water molecules in steam are bigger than those in ice

Activities for Conceptual Change:

• Become aware of ideas
• Expose their beliefs by sharing them
• Confront their beliefs by testing them
• Resolve conflicts between their ideas and observations
• Extend the concept by making connections with other relevant ideas

Pre-test: Mass and Volume Diagnostic Assessment Items.

Question: Jonathan has three cubes (one made of cork, one made of wood and one made of metal). Since they all have the same volume and none of them are hollow, will they have the same mass?
A. Yes, they will have the same mass, since they have the same volume.
B. No, they will not have the same mass, because they are made of different substances.

(Developed by the Chantier 7 project team members )

• Consistencies or inconsistencies in the use of student alternative ideas may be revealed through polling.
• Ask students from each response group to explain why they chose this option. Do not confirm or deny their beliefs.

Demo #1

• Show two blocks of different density with of the same size/volume and of metal composition (slightly different colours).
• Lead in- emphasize the volume: Do we agree that these two cubes are the same size and therefore occupy the same space?
• Prediction Question: Are the masses of these two cubes the same? (Poll using a form)

Observe: Demo- Using those two cubes and a balance. Demonstrate that the mass of both cubes are different. Students record the masses obtained.

Experiment: Students mass several cubes (2 more) of the same size and record their masses in order to observe a trend in their data.

Explain: Students answer 2 questions:

• How is it possible for two objects to occupy the same space but have different masses?
• Draw what you think is inside each of the cubes below.

Resolve Conflicts:

• Choose 3 models from student drawings. (1 accurate drawing, and 2 misconceptions that have potential to generate discussion)
• Present these models to the class and discuss their similarities and differences. Lead the discussion towards how to represent a particle model. 

Focus: More particles = more mass. Larger particles = more mass, when the amounts are the same. Students may understand that different particles have different sizes. 

Demo #2  

• Two large test tubes are filled with two different liquids (same mass but different volumes).
• Lead in- emphasize the volume: Do we agree that these two jars contain liquids that occupy different amounts of space?
• Prediction Question: Are the masses of these two liquids the same? (Poll using a form)

Observe: Demo- Using those two jars and a balance. Demonstrate that the mass of both jars is the same. Students record the masses obtained.

Experiment: Students mass several liquids and record their masse and respective volume to observe the trends in their data.

Explain: Students answer 3 questions:

• Do all objects of the same mass have the same volume?
• How is it possible for two objects to have the same mass but have different volumes?
• Draw what you think is inside each of the liquids.

Resolve Conflicts:

• Choose 3 models from student drawings. (1 accurate drawing, and 2 misconceptions that have potential to generate discussion)
• Present these models to the class and discuss their similarities and differences. Lead the discussion towards how to represent a particle model. 

Focus: Empty space between particles or the size of particles may differ. # of particles should remain the same.

Post-test: Redo the assessments items with the students as a post test. Answers should be revealed. More questions can also be used.