ScienceEnergyAges 11–12

Energy can't be created or destroyed

Explain the principle of conservation of energy (energy cannot be created or destroyed, only transferred between stores), and describe how energy is dissipated as thermal energy to the surroundings in all real processes

Lesson

Set out your lesson

Track useful and dissipated energy without making any energy disappear.

Before teaching

Use this short check, then start teaching.

Activity

Name one energy store and one transfer pathway. Ask where energy goes when a moving toy slows. If stores and pathways are confused, revisit the two hard prerequisites first.

If Not Ready

Pause and explicitly teach or revisit the named hard prerequisite; do not treat its allocation or authored status as learner readiness.

Printer, credit, and teaching notes

About 20 minutes. Use Show, G and T1 cards on screen, scrap paper and a pencil. No real charger or powered device. Show one card at a time; put models and adult key aside before Try.

Use the complete materials on screen or print only the current sheet. Keep adult guidance out of learner view.

Next: Show

Adult extras

Teaching limits and safe use

These are finite task opportunities, not proof of mastery. Record what was attempted and what support was used.

Supplied joules are illustrative, not observed measurements.
Canonical closed-system statement retained in provenance but qualified in teaching.
These bounded source-based examples and task opportunities do not establish learner mastery or general scientific performance.

Use the supplied paper cases only unless the optional paper prototype test is explicitly chosen. Do not handle electrical chargers, heat materials, mix chemicals, approach floodwater or volcanoes, or disturb animals. For the optional prototype, an adult checks a clear tabletop; use only paper and a blunt pencil, keep paper away from faces, and stop if the setup feels unsafe. Missing equipment, discomfort or no test means not performed: leave observations blank. No personal health, disaster or family experience is required.

Retain your actual plan and observations on paper between steps. If not performed, leave results blank. Record response mode and assistance; do not infer mastery.

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1858 concepts · 9 subjects

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Track useful and dissipated energy without making any energy disappear.

Family records and proof options

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Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.

View learner plans ($12/mo per learner) See sample family archive

Learning resources

Extra practice links — they do not replace Gakuva’s teaching approach.

PhET Interactive Simulations · Practice link — not the full lesson

Energy Forms and Changes

Open practice(new tab)

Before you open · source notes

Energy Forms and Changes supports hands-on exploration for Energy can't be created or destroyed. Not every lab worksheet.

Free interactive page, no sign-in required for the tested path.

Before you open

Ask the learner what they changed in the sim or page and what they observed.

Opening this link does not save learning or assess mastery.

Source, access and review notes

Public PhET Interactive Simulations page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.

PhET Interactive Simulations. “Energy Forms and Changes.” External page; Gakuva does not copy, host, embed, or redistribute materials.

Unknown — link only

Check understanding

States the law of conservation of energy
Explains why the total energy in a closed system is always the same even though it changes form
Explains what dissipation means and why it happens in real machines (friction, air resistance)
Gives an example showing why 'wasted' energy is not lost but transferred to the surroundings

“If your child charged their phone overnight and was asked where the electrical energy goes, could they explain what conservation of energy means — and why the charger gets warm even though that heat isn’t doing any useful work?”

Curriculum record

Type: Conceptual
Subject: Science
Domain: Energy
Age range: Ages 11–12

Standards

ngss-ms:MS-PS3-5uk-nc-2013:KS3.Sci.Phys.Energy.2