Back to the Sun
A 60-minute Grade 5 lesson on modelling how the energy in an animal's food was once energy from the sun.
Back to the Sun is a free 60-minute Grade 5 science lesson plan for Common Core standard 5-PS3-1 — model how the energy in food started out as energy from the sun. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Grade 5
- Length:
- 60 minutes
- Standard:
- 5-PS3-1
Grade 5 · Physical Science
5-PS3-1
Use models to describe that energy in animals’ food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun.
Objective
Students will be able to trace the energy in a meal back to sunlight through every step.
Students are successful when they can
- Starts every chain at the sun.
- Names each transfer in order.
- Explains why the chain cannot start with the animal.
What you need
- Food cards, arrow cards, a class meal to analyse
- Photographs of a pasture, a wheat field and an orchard
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up
5 min- Ask where the energy in a cheese sandwich came from.
- Keep asking 'and before that?' until somebody says the sun.
Teach — every arrow, all the way back
15 min- Build the beef chain: sunlight, grass, cow, person.
- Ask what the grass did with the sunlight. Made food and grew.
- Build a plant-only chain: sunlight, wheat, cereal, person.
- Ask whether any chain can start somewhere other than the sun. Not for food.
- Show energy lost at each step and say why chains are short.
- Say what the model is for: it shows food as stored sunlight.
“And before that? Keep going until you reach the sun.”
Investigate — trace a real meal
22 min- Groups take one item from today's school lunch.
- They build the full chain back to sunlight with arrow cards.
- They mark every point where energy is lost.
- They compare a plant-only chain with one that includes an animal.
Independent practice
15 min- Students complete the 'Back to the Sun' page.
- Check every chain starts at the sun.
Close
3 min- Ask which chain wastes least energy, and why that matters.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Starts the chain at the animal.
Why: The animal is what you eat.
Fix: Where did the animal's energy come from? Keep going.
Thinks plants get energy from the soil.
Why: Roots are in the soil.
Fix: Soil supplies water and minerals. The energy comes from sunlight.
Thinks energy is recycled like matter.
Why: Matter cycles, so energy might.
Fix: Energy flows one way and is lost as heat. Matter cycles; energy does not.
If they are not there yet
- A three-step chain with the middle supplied.
- Cards to order rather than build from scratch.
If they finish early
- Trace a chain with three animals in it.
- Explain why there are few animals at the end of long chains.
- Say where the energy in coal originally came from.
Exit ticket
Trace the energy in a beef sandwich back to its original source.
What to look for: Sunlight to grass to cow to person, with the sun named as the origin. Starting at the cow means the trace-back step is incomplete.
Printable practice for 5-PS3-1
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Back to the SunNumber the steps from 1 to 4.
Questions about Back to the Sun
How long does the Back to the Sun lesson take?
60 minutes, split across 5 timed sections: warm-up 5 min, teach 15 min, investigate 22 min, independent practice 15 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does Back to the Sun teach?
5-PS3-1 — 5-PS3-1, Physical Science for Grade 5: “Use models to describe that energy in animals’ food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun.” In plain terms, model how the energy in food started out as energy from the sun.
What do I need to teach this lesson?
Food cards, arrow cards, a class meal to analyse, photographs of a pasture, a wheat field and an orchard and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: starts the chain at the animal; thinks plants get energy from the soil and thinks energy is recycled like matter. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “Trace the energy in a beef sandwich back to its original source.” Sunlight to grass to cow to person, with the sun named as the origin. Starting at the cow means the trace-back step is incomplete. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with Back to the Sun?
Yes — 1 printable 5-PS3-1 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is Back to the Sun free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 8 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-08. Aligned to 5-PS3-1 of the Next Generation Science Standards.