Lesson Plan

2. Explore the gravitational potential energy store

KS4-18-02

Intent

Lesson Outcomes

  • Recall the equation to calculate gravitational potential energy (GPE)
  • Use values for GPE to calculate the theoretical velocity of an object
  • Explain why the maximum theoretical velocity is never actually reached

National Curriculum

  • Energy changes in a system involving heating, doing work using forces, or doing work using an electric current
  • Calculating the stored energies and energy changes involved

Working Scientifically

  • Use an appropriate number of significant figures in calculation
  • Interconvert units

Resources

Resources: Class presentation and handout.

Handout: Summarise the work of Kelvin and Rankine. Worked examples of how to use the equation. Practice using the formula in GPE calculations. Apply knowledge of KE and GPE to decide which statements match the 2 types of energy.

Rocket words

  • scientific calculator
  • GPE
  • mass
  • velocity
  • theoretical

Implementation

Starter

What are the 3 factors which affect gravitational store, mass, temperature, speed, length, height or volume? Discuss this question. Deduce by exclusion of those factors that are not applicable. Evolve the discussion to draw a simple definition from students.

Main Teaching

Use the class presentation to explore the gravitational potential energy store with the students. Using the handout, ask the students to consider the influence of the Scottish partnership of Kelvin and Rankine and their joint contribution to formalising the foundational knowledge from Newton and the Ancient Greeks. Practice the rearrangement of the formula to solve for the missing variable. Use the final table to reinforce understanding.

Career Film: This is Ruth Davey. Ruth works as an Experimental Rig Operator for National Nuclear Laboratory.

Expert Film: This is Dr. Tim Gregory, who works as a Chemical Analyst for National Nuclear Laboratory. Tim talks about the gravitational potential energy store.

Mission Assignment

Using the handout, ask the students to consider the influence of the Scottish partnership of Kelvin and Rankine and their joint contribution to formalising the foundational knowledge from Newton and the Ancient Greeks. Practice the rearrangement of the formula to solve for the missing variable. Use the final table to reinforce understanding. Research the gravity experiment of Galileo. What did he learn from his experiment at the Tower of Pisa? Practice calculating GPE; try changing the gravity to that of the moon or Mars. Rearrange the equation to solve for height or gravity. Explain why a rocket leaving the earth requires so much energy in thrust compared to a rocket leaving the moon.

Challenge Task: Use ideas about GPE to explain why it should - theoretically - be easier to go mountain climbing on the moon. In practice, why would it not be easier for the astronaut?

Impact & Assessment Opportunities

Plenary

Use the summative quiz to assess students' learning. Does an object on the ground have a potential energy of zero? What would the object's position need to be? Why do we make this assumption?