Science lesson plan · 10th grade (Year 11 in England) · 60 minutes
Energy stored in a stretched spring (E = ½ k e²)
Energy
CCSS NGSS.HS-PS3-1England: GCSE Combined Science: Energy (elastic potential energy)
Objective and success criteria
Students will: Energy stored in a stretched spring (E = ½ k e²).
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Stretching springs: extension and Hooke's law; Kinetic and gravitational potential energy
Leads to: the next skill in this area.
Materials: Wind-up toys or a pendulum, Energy transfer diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (Stretching springs: extension and Hooke's law; Kinetic and gravitational potential energy). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A spring is 12 cm long. When a weight is hung on it, it is 16 cm long. What is the extension, in cm? → 4 cmPrompt: Extension is how much longer the spring has become.
- What is the kinetic energy of a 80 kg object moving at 5 m/s? Use Eₖ = ½ m v². → 1000 JPrompt: Square the speed first.
- A spring has a spring constant of 80 N/m. What force is needed to stretch it by 5 cm, in N? (F = k × e, with e in metres) → 4 NPrompt: Convert the extension to metres first.
Hook · 6 min
- Wind up a toy or stretch an elastic band and ask where the energy goes.
- Share the objective: Energy stored in a stretched spring (E = ½ k e²). Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A spring with spring constant 100 N/m is stretched by 0.05 m. How much energy is stored in it, in J?
- Step 1: 0.5 × 100 × 0.05² = 0.125
- Step 2: So the answer is: 0.125 J
- Answer: 0.125 J
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A spring with spring constant 50 N/m is stretched by 0.2 m. How much energy is stored in it, in J? → 1 JPrompt: E = ½ × k × e²
- A catapult band has a spring constant of 200 N/m and is pulled back 20 cm. How much elastic potential energy is stored, in J? Give 3 decimal places. → 4 JPrompt: Convert cm to m first.
You do: independent practice · 17 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A spring with spring constant 50 N/m is stretched by 0.5 m. How much energy is stored in it, in J? → 6.25 JPrompt: E = ½ × k × e²
- A catapult band has a spring constant of 50 N/m and is pulled back 20 cm. How much elastic potential energy is stored, in J? Give 3 decimal places. → 1 JPrompt: Convert cm to m first.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Stretching springs: extension and Hooke's law.
- Use concrete materials: wind-up toys or a pendulum.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-10.
Free lesson plan from eurekami.com/lesson-plan-builder