IGCSE Physics: W=mg | Edexcel Modular | Unit 1 | L11

IGCSE Physics: W=mg | Edexcel Modular | Unit 1 | L11

This lesson covers spec point 1.18 — knowing and using the relationship between weight, mass and gravitational field strength: W = mg.

PowerPoint includes:
• Retrieval starter reviewing F = ma calculations
• Direct Instruction (I Do) — mass defined (amount of matter, constant regardless of location); weight defined (gravitational force, varies with location); W = mg introduced; g = 10 N/kg on Earth defined; planetary gravity table showing g values for different bodies in the solar system; worked examples calculating weight, mass and g
• Guided Practice (We Do) — calculate weight on Earth; calculate weight on the Moon; compare mass and weight for the same object on different planets
• Independent Practice (You Do) — W = mg calculations on Earth and other planets; explain why weight changes but mass does not; multi-step problems combining W = mg with F = ma
• Review and Reflect — 3 MCQs and exit ticket

Activity Sheet includes:
• Formula box: W = m × g
• Planetary gravitational field strength reference table
• 10 exam-style questions covering W = mg calculations, the mass vs weight distinction, and planetary contexts
• Stretch question combining W = mg and F = ma in a multi-step problem
• Full mark scheme for teacher use