Week 2: Week 2 Content

Grade 8 Science | Rosche | Kairos Academies

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Learning Support

100% Digital Lesson

This lesson uses the PhET Forces and Motion simulation and Google Forms for all activities. The only physical material is one worksheet to write F=ma formulas.

NGSS Standards Covered This Week

MS-PS2-2 (Primary Standard)

What it means: Plan an investigation to provide evidence that the change in an object's motion depends on the sum of the forces on the object and the mass of the object.

In student language: I can use the formula F=ma to calculate force, mass, or acceleration.

Spiral Standards from Week 1

  • Newton's First Law: Objects resist changes in motion (inertia)
  • Newton's Third Law: Action-reaction force pairs (qualitative understanding)

The Phenomenon: Shopping Cart Challenge

Learning Targets

By the end of this week, you will be able to:

Success Criteria ā€“ How You'll Know You've Got It

Target 1: Calculate force using F=ma (Newtons = kg Ɨ m/sĀ²)

Self-check: Can I plug values into F=ma and get the correct answer with units?

Target 2: Calculate net force when multiple forces act on same object

Self-check: Can I add forces in the same direction and subtract opposite forces?

Target 3: Draw and interpret free-body diagrams

Self-check: Can I show all forces as arrows with correct direction and relative size?

Target 4: Explain why heavier objects need more force for same acceleration

Self-check: Can I explain the shopping cart phenomenon using a=F/m?

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You're at the grocery store. When the cart is EMPTY, you push it and it accelerates quickly. When the cart is FULL of groceries, you push with the SAME FORCE, but it barely moves!

Why does a shopping cart get harder to push when it's full?

Focus Question: What is the mathematical relationship between force, mass, and acceleration?

Worked Example

Common Mistake: Force vs. Motion

WRONG: "You need force to keep something moving at constant speed."
RIGHT: "You only need force to CHANGE motion (accelerate). Objects maintain constant speed without force (Newton's First Law)."
KEY: Force causes ACCELERATION, not motion itself!

Step-by-Step Problem Solving

Problem Scenario

Review the problem scenario and work through each step below.

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Formulas This Week: You'll learn THREE forms of the same relationship: F = ma, a = F/m, m = F/a

Vocabulary

Key Vocabulary (5 terms) ā€” Practice Tool
Term Definition
Force (F) A push or pull; measured in Newtons (N)
Mass (m) Amount of matter; measured in kilograms (kg)
Acceleration (a) Change in velocity; measured in meters per second squared (m/sĀ²)
Net Force Sum of all forces acting on an object (add same direction, subtract opposite)
Free-Body Diagram Visual representation of all forces acting on an object (shown as arrows)
Enrichment & Extension
Optional deep dives for early finishers.

Optional content if you finish early or want to go deeper.

Scientist Spotlight

Research a scientist who contributed to this week's topic area and describe their key findings.

Environmental Justice Connection

Explore how this week's science concepts connect to environmental justice issues in our community.

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