Science Lesson Kit · Teacher Resource
Force, Mass & Change in Motion — 5E Lesson Plan
Physical Science · 55 minutes
Grade 6
5E lesson flow
01
Engage
7 min
Teacher Does
Show balanced and unbalanced force diagrams.
Students Do
Predict whether motion should change.
Ask
- What is the net force?
Look For
Direction and zero versus nonzero net force.
02
Explore
15 min
Teacher Does
Model a force-only investigation, then a mass-only investigation.
Students Do
Identify independent, dependent, and controlled variables.
Ask
- What must stay the same?
Look For
One main variable changes at a time.
03
Explain
10 min
Teacher Does
Connect repeated evidence to the force and mass patterns.
Students Do
Write evidence-limited claims.
Ask
- What does the dataset support?
Look For
Greater force -> larger change; greater mass -> smaller change for the same force.
04
Elaborate
14 min
Teacher Does
Present a flawed two-variable plan.
Students Do
Redesign it and justify the controls and number of trials.
Ask
- How will you know which factor mattered?
Look For
Isolated variable and repeated trials.
05
Evaluate
9 min
Teacher Does
Assign the transfer worksheet.
Students Do
Analyze the new dataset.
Ask
- Does your claim stay inside the tested conditions?
Look For
Specific values, units, and cautious wording.
Student goal
I can plan and use fair-test evidence to explain how net force and mass affect changes in motion.
Learning objectives
- Distinguish balanced forces from an unbalanced net force and predict whether motion should change.
- Plan a fair investigation that changes force or mass one variable at a time while controlling the other conditions.
- Use repeated-trial evidence to explain why a larger net force produces a larger change in motion, while a larger mass produces a smaller change for the same net force.
Materials
- Low-friction carts or safe rolling objects
- Spring scales or calibrated pull method
- Mass blocks
- Meter tape
- Timer or motion-measurement tool
- Investigation planning sheet
Before class
- Choose a straight one-dimensional track.
- Mark one reference direction as positive/right.
- Prepare at least three force levels and three mass levels.
- Keep trials low-speed and repeatable.
Prior knowledge
- Students can describe pushes and pulls with direction.
- Students can read simple tables and compare repeated measurements.
Vocabulary
- net force
- The overall force after the forces on an object are combined with direction.
- balanced forces
- Forces that combine to a net force of zero.
- unbalanced forces
- Forces that combine to a nonzero net force and can change an object's motion.
- mass
- The amount of matter in an object, measured here in grams.
- change in motion
- A change in speed, direction, or both, described from a stated reference frame.
- independent variable
- The factor deliberately changed in an investigation.
- dependent variable
- The factor measured as the outcome.
- control
- A condition kept the same so the comparison is fair.
Differentiation
- Provide a variable/control organizer.
- Use arrows and direction labels before introducing net force language.
- Allow oral evidence explanations before writing.
- Extension: ask students to compare two possible investigation designs and defend the stronger one.
Assessment
- Check correct net-force direction.
- Check that only one main variable changes.
- Require evidence with units and a stated reference direction.
- Check that students do not confuse equal force with equal motion change across different masses.
Exit ticket
For the same cart, what should happen to the change in motion as net force increases? What must stay controlled?
Extension
Design a repeatable investigation that tests mass while keeping net force constant.