Gravity - Objects with Different Mass (Lilach Cary)

Author

Lilach Cary

Principle(s) Illustrated

1. Acceleration due to gravity is 9.8 m/s/s, regardless of the mass of the object; therefore, objects with different masses accelerate downward at the same rate

2. Speed equals total distance divided by total time.

3. Students develop their own experimental design to test their hypothesis.

Standards

• MS-PS2-2

  • Plan an investigation to provide evidence that the change in an objects motion depends on the sum of the forces on the object and the mass of the object.

• MS-ETS1-1

  • Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

• MS-ETS1-2

  • Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

• MS-ETS1-4

  • Develop a model to generate data for iterative testing and modifications of a proposed object, tool, or process such that an optimal design can be achieved.

Questioning Script

Prior knowledge & experience:

Gravity causes objects to accelerate in a downward motion.

Objects with greater masses have larger gravitational pulls.

Root question:

The greater an object's mass, the stronger is the force of gravity on the object. Does this mean that more massive objects fall more quickly than less massive objects? Design an experiment to answer this question.

Target response:

Objects with different masses will fall at the same rate and land at the same time****

****This excludes things like feathers and paper. Students always want to test these, but they get too much air resistance.

Common Misconceptions:

Students typically believe that objects that are more massive will fall faster than objects with lesser mass. This could possible be because they have seen this happen in water, where objects that are more dense fall to the bottom of a body of water more rapidly, or because more massive objects are able to pull things with greater force.

Photographs and Movies

References

Pearson Science: Physical Science Lab Manual