The goal of this activity is for students to determine that objects in free fall on Earth experience an acceleration of 9.8 m/s2 and that the force of gravity acts on all objects on Earth at a ratio of 9.8 N of force for every kilogram of mass.

In the Preliminary Observations, students observe falling objects and hold and/or lift similarly-shaped objects of different mass.

During their investigations, students should determine that objects without appreciable air resistance fall at 9.8 m/s2 regardless of mass and that for every kilogram of mass, gravity pulls with an additional 9.8 N of force.

You may choose to have half the lab groups perform one investigation and half perform the other investigation, or choose to have all groups do both parts.


  • Identify variables, design and perform investigations, collect and analyze data, draw a conclusion.
  • Relate acceleration of gravity on Earth (g) and gravitational field strength on earth.