Lesson Plan

• Describe what a field of force is and give examples such as electric, magnetic and gravitational fields.
• Define the gravitational field as force per unit mass and state its SI unit (m s⁻²).
• Calculate the magnitude of the gravitational field of a point mass using g = GM/r².
• Explain that the gravitational field vector points radially inward toward the source mass.
• Apply the relationship F = m g to determine the weight of an object in a given field.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with practice problems
• Scientific calculators
• Diagram of a spherical mass with radial field vectors (handout or slide)
• Laptop for a simple field‑simulation (optional)

Begin with a quick question: “What do we mean by a ‘field’ in physics?” Connect to students’ prior work on electric and magnetic fields. State that by the end of the lesson they will be able to describe a gravitational field, write its formula, and use it to find forces.

1. Do‑Now (5') – short quiz on the concept of a field of force from the previous lesson.
2. Mini‑lecture (10') – introduce the gravitational field, derive g = F/m, discuss units and dimensions.
3. Demonstration (8') – show a simulation/diagram of radial field lines around a mass; highlight inward direction.
4. Guided practice (12') – work through the Earth‑surface example; students complete the worksheet calculation.
5. Comparison activity (7') – fill in a table comparing gravitational, electric, and magnetic fields using the provided chart.
6. Check for understanding (5') – exit ticket: write the formula for g and explain its direction in one sentence.

Summarise that a gravitational field is a vector field representing force per unit mass, follows an inverse‑square law, and always points toward the source. Collect exit tickets and assign homework: additional problems calculating g for various masses and distances, to be turned in next class.