Whole Earth Curriculum WEC

Lesson 08 — Energy Transformations in Action

Learners follow energy through whole chains of change — food to motion to heat, and sunlight to food to electricity to light — and see that at every step energy changes form and some always escapes as heat. They build their own chains with cards and trace the input and output of everyday devices.

D06 P3: Intellectual & Cognitive Awareness D06.S3 50 minutes Draft

Objectives

Essential question

How does energy change through a chain of forms in the real things we use every day?

transformationchaininputoutputsolarphotosynthesiswaste heat

Materials

Standard materials

Low-tech / no-cost

Enriched / lab & device

Works in different contexts

A diagram of two energy transformation chains. The top chain shows a plate of food labeled 'chemical energy,' an arrow to a running person labeled 'kinetic energy,' and an arrow to a wavy heat symbol labeled 'thermal energy (waste heat).' The bottom chain shows the Sun labeled 'light energy,' an arrow to a leaf labeled 'chemical energy (photosynthesis),' an arrow to a battery and bulb labeled 'electrical energy,' and an arrow to a lit bulb labeled 'light + heat.' A caption reads: at every step, energy changes form, and some always leaves as heat. Labels, arrows, and shapes, not color alone, carry the meaning so it prints clearly in grayscale.
A diagram of two energy transformation chains. The top chain shows a plate of food labeled 'chemical energy,' an arrow to a running person labeled 'kinetic energy,' and an arrow to a wavy heat symbol labeled 'thermal energy (waste heat).' The bottom chain shows the Sun labeled 'light energy,' an arrow to a leaf labeled 'chemical energy (photosynthesis),' an arrow to a battery and bulb labeled 'electrical energy,' and an arrow to a lit bulb labeled 'light + heat.' A caption reads: at every step, energy changes form, and some always leaves as heat. Labels, arrows, and shapes, not color alone, carry the meaning so it prints clearly in grayscale.

Lesson 8 — Energy Transformations in Action

Summary

Learners follow energy through whole chains of change — food to motion to heat, and sunlight to food to electricity to light — and discover that at every step energy changes form, and some always escapes as heat. They build their own chains with cards and trace the input and output energy of the devices and actions they use every day.

Objectives

  • Describe how energy changes between forms through a chain of transformations. (D06.S3.06.01)
  • Use the chain to record and read energy data, revisiting how organized data supports a claim. (D06.S1.06.01)

Connection

Nothing uses energy only once. The food you ate became the motion of your day and then the warmth of your body. Sunlight became the food a plant made, and that food — or the fuel pressed from old plants — became the electricity that lights a lamp. Every useful thing is a chain of changes, and at the end of every chain some energy slips away as heat. Today you follow the chain from start to finish.

Materials

  • Transformation chain diagram
  • Chain cards
  • Transformation tracker page

Preparation

  • Print or draw the diagram, chain cards, and tracker page.
  • Recall Lesson 7: the five forms of energy. Today we link them into chains.
  • Have a candle, a wheel, or a hand-crank light ready if using the feel-it activity.

Facilitator note

Written to the learner (“you”). The key idea to land: a transformation is a chain — each output becomes the next input — and some energy always leaves as heat. Model the worked example by building the food chain aloud, form by form, and pointing to the “waste heat” at the end. Two distinctions worth naming: energy changes form (this lesson’s standard) versus energy is conserved (Grade 9 — do not require the quantitative law now; just note “none of it disappears, though some becomes heat we cannot easily reuse”). The honest technology/environment lens: every machine wastes some energy as heat, which is why using less and using energy well matters — a value we hold, stated alongside the evidence. Global examples (a solar cooker, a water wheel, a bicycle, a cooking fire) keep it faithful to many lives. See docs/facilitation.md.

Procedure

  1. Gather (5 min). Recall the five forms from Lesson 7. Now the question: what happens when energy changes more than once, step after step?
  2. Meet the chains (10 min). Look at the diagram. Follow the top chain: chemical (food) → kinetic (running) → thermal (warm body). Follow the bottom chain: light (Sun) → chemical (the leaf’s food, made by photosynthesis) → electrical (battery) → light + heat (bulb). At every arrow, energy changes form — and a little leaves as heat.
  3. Build chains (15 min). With your cards, build three chains in order. Start each with a beginning form and end with heat: food → motion → heat; Sun → plant → food; battery → electrical → light → heat. Check each arrow with a partner: “does this form become that one?”
  4. Trace input and output (10 min). On your tracker page, pick three things — a bicycle, a cooking fire, a lamp — and write its input energy and its output energy (including the heat that escapes). What pattern do you see?
  5. Close (5 min). Energy is a traveler that changes clothes at every stop, and always leaves a little warmth behind. Follow any chain far enough and you end at heat.

Differentiation

  • Support: Provide pre-ordered two-card chains with the end blank; focus on naming each form aloud and finding the heat.
  • Extension: Compare two devices (a lamp and a hand-crank light) and explain, using the chain, which wastes more energy as heat and why that matters for using energy well.

Assessment

  • Formative (observation): Can the learner order a three-step chain and name the form at each step and the heat that escapes?
  • Self-check: The learner asks, “For any device, can I trace the energy back step by step and forward to the heat?”

Home connection

Pick one thing you use (a phone, a stove, a bicycle) and trace its energy chain out loud to someone — every form it passes through, ending in heat.

Resources