⚡ Energy Transfer in a Closed System — Simulation Overview
Four interactive tabs, each modelling a different closed system scenario in line with AQA GCSE Physics.
🕰️ Tab 1 — Pendulum
A bob hangs from a pivot on a cord. Students drag the bob to any angle and release it. The bob swings continuously, with real-time energy bars showing GPE and KE updating every frame using the correct physics: KE = ½L²ω² and GPE = gL(1−cosθ). At the swing tips the bob glows green (all GPE); at the bottom it glows amber (all KE). A dashed arc shows the swing path and a height line labelled h connects the bob to the equilibrium position. The total energy line across the top of the bars stays flat — demonstrating conservation visually.
🏔️ Tab 2 — Roller Coaster
A cart travels along a multi-hill track automatically, or students can drag it manually to any position. Speed is calculated at every point using v = √(2gΔh). The cart colour shifts between amber (KE) and green (GPE) as it moves, and the bars mirror this exactly. Height is shown with a dashed vertical line. Students can pause mid-run and observe the relationship between hill height and speed directly.
🏀 Tab 3 — Bouncing Ball
Students tap or click anywhere on the canvas to drop the ball from that height. Each bounce applies a coefficient of restitution (e = 0.82, realistic for a rubber ball), so a small fraction of energy transfers to a thermal store on every impact. Three bars — KE, GPE, thermal — are shown. As bouncing continues, thermal grows steadily while KE and GPE decrease, but the total stays constant. A red thermal glow builds up on the floor at the impact point. This directly addresses the common GCSE misconception that energy is “lost” on bouncing — it isn’t, it moves to the thermal store.
🌡️ Tab 4 — Hot Object
A hot block sits inside a thermally insulated box alongside cooler surroundings. Students drag a slider to set the starting temperature (50–350°C). Thermal energy flows from the hot block to the surroundings (shown by an animated dashed arrow), and both temperatures update in real time. At equilibrium the temperatures meet at the midpoint and the simulation pauses before resetting. Energy bars on the right show the two stores at all times — their sum never changes, reinforcing the closed system principle. The insulated box visually explains why no energy leaves.
🧑🏫 Suggested Classroom Activities
Starter (5 min) — True or False?
Display three statements before opening the simulation. Students vote hands-up:
- “A pendulum loses energy as it swings.” (False — ideal closed system)
- “When a ball bounces, energy disappears.” (False — it transfers to thermal)
- “A hot object in an insulated box will cool forever.” (False — it reaches equilibrium)
Reveal answers using the simulation after voting.
Activity 1 — Pendulum Predict and Observe (Tab 1)
Step 1: Before releasing, ask: “Where will KE be highest? Where will GPE be highest?” Students sketch a prediction on a mini-whiteboard.
Step 2: Drag the bob to 45° and release. Watch the bars.
Discussion prompts:
- What happens to the bars at the very tip of the swing?
- What would happen to the bar heights if you dragged to a smaller angle — and why?
- Switch to Very Slow speed. Can you pause it exactly when KE = GPE? What does that tell you about height at that moment?
Activity 2 — Roller Coaster Speed Challenge (Tab 2)
Set up: Drag the cart to the top of the tallest hill. Note the height using the dashed line.
Task: Using v = √(2gΔh), predict the speed at the lowest valley (Δh ≈ the full drop). Compare your prediction to the bar — if GPE bar drops to near zero at the valley, the KE bar should be near maximum.
Extension: Does it matter which valley you predict for, or just how far it is below the starting point? Why? (Links to the idea that only height difference matters, not the path taken.)
Activity 3 — The Bouncing Ball Audit (Tab 3)
Step 1: Click near the very top of the canvas for maximum drop height. Count the bounces until the ball barely moves.
Task: Every 3 bounces, pause and record approximate bar heights (KE, GPE, thermal %) in a table.
| Bounce | KE % | GPE % | Thermal % | Total % |
|---|---|---|---|---|
| 0 | ||||
| 3 | ||||
| 6 | ||||
| 9 |
Key question: Does the total ever change? What does this prove about energy in a closed system?
Follow-up: What does the thermal store represent in a real bounce? (Heat generated in the ball and floor due to deformation — sound energy is also transferred in reality.)
Activity 4 — Cooling Curve Investigation (Tab 4)
Step 1: Set the slider to 300°C. Watch the temperatures for 20 seconds.
Step 2: Drag the slider back and set it to 100°C. Watch again.
Discussion:
- Does the block reach the same final temperature in both cases? Why?
- Does the total bar height change? What principle explains this?
- Why does the box need to be insulated for this to be a closed system?
Extension — real-world link: In what situation might a classroom or home act as a closed thermal system? (Double glazing, draught-proofing, insulated loft — links to energy efficiency in buildings, which connects to Peter’s sustainability background nicely.)
Exit Ticket (5 min)
Three questions on mini-whiteboards or paper:
- In a pendulum, where is KE at a maximum?
- A ball bounces 10 times and comes to rest. Where has its energy gone?
- A hot metal block is placed in an insulated box. What happens to the total thermal energy of the system?