Sunlight Across Planets

Overview

This is lesson 7 of 10 in Exploring Our Cosmic Playground. Students use a simple distance model and hands-on observations to investigate how the Sun’s light and heat change across the Solar System. The lesson builds on earlier learning about the eight planets and their order from the Sun.

Learning intentions

• WALT investigate how the Sun’s heat and light affect the eight planets differently.
• WALT use a model to compare planetary distances from the Sun.
• WALT make predictions and explain them using observations.
• WALT use a thermometer and magnifying glass safely and carefully.

Success criteria

• I can describe how distance from the Sun affects heat and light.
• I can predict which planets are likely to be hottest and coldest.
• I can use a model and observations to explain my thinking.
• I can order the eight planets from hottest to coldest in a simplified model.

Curriculum links

• Earth and Space — using models and simulations to investigate the relative spacing and movement of celestial bodies.
• Earth and Space — identifying planets as celestial bodies within the Solar System.
• Science capabilities — observing, interpreting evidence, communicating ideas, and using simple models.
• Key competencies — thinking; managing self; participating and contributing; using language, symbols, and texts.

Lesson structure (45 minutes)

1. 0–5 min · Hook and recall. Teacher opens with the hook and recall slides and asks, “Would you rather stand close to the Sun or far away? Why?” Students turn and talk, then recall the order of the eight planets using actions or a class chant. Establish that the Sun gives Earth light and heat.

2. 5–12 min · Build the idea. Teacher uses the Sunlight and distance slides to show a torch or lamp shining on objects at different distances. Explain that light spreads out as it travels, so planets farther from the Sun generally receive less light and heat. Students observe the beam and use their hands to show “more” and “less” light. Clarify that this is a simplified model: planets also have different atmospheres and surfaces. In real planetary data, Venus has the hottest average surface temperature, while Mercury can become extremely hot in daytime; Neptune is the coldest of the eight planets.

3. 12–25 min · Hands-on investigation. Teacher places eight planet markers in order along a labelled “Solar System distance line”: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. In groups of four or five, students use a thermometer to compare the temperature near a lamp or sunny window at two or three marked distances, without looking directly at the lamp or Sun. They use magnifying glasses to compare the brightness and apparent size of a small light-coloured card at each distance. Students record observations on the guided Sunlight and Heat investigation sheet. Rotate roles: equipment manager, measurer, recorder, and reporter.

4. 25–33 min · Predict and compare. Teacher pauses the investigation and asks, “What do you notice as the distance increases?” and “Which planet would probably receive the least light?” Students place planet picture labels on a floor or desk model, then make a group prediction for the hottest and coldest planets. Each group gives one evidence-based sentence, such as, “Neptune may be coldest because it is farthest from the Sun.”

5. 33–40 min · Apply learning. Teacher displays the prediction and discussion slides and presents three scenarios: a planet close to the Sun, one in the middle, and one very far away. Students show a numbered card or fingers to indicate which receives the most light, then explain their choice. Students complete the final prediction and explanation on the worksheet. Support students to use the sentence frame: “The ___ is closer/further from the Sun, so it receives ___ light and may be ___.”

6. 40–45 min · Plenary and exit check. Teacher uses the plenary slides to revisit the WALT and asks students to share one new idea. Students complete the worksheet exit response: “The planet likely to be coldest is ___ because ___.” Collect sheets as students pack away equipment safely.

Resources

• the complete Sunlight Across Planets slide deck
• the guided Sunlight and Heat investigation sheet
• Eight labelled planet picture cards or markers
• Torch, lamp, or safe bright light source
• Three or four classroom thermometers
• Magnifying glasses
• Small white or light-coloured cards
• Tape, metre ruler, and large floor or desk space
• Role cards or a simple group-role display

Assessment

• Listen for students linking distance with the amount of light and heat, rather than simply naming a planet.
• Check group observation sheets for sensible comparisons, careful thermometer use, and predictions supported by evidence.
• Use the final sentence to identify who can explain the relationship independently and who needs further modelling.

Differentiation

• Provide guided observation sheets with pictures, fewer recording boxes, and the sentence frame: “Closer means ___ light/heat; further means ___ light/heat.”
• Offer planet temperature picture cards, oral rehearsal, partner talk, and teacher or peer scribing for students who need language or writing support. Pre-teach Sun, light, heat, closer, further, hotter, and colder with gestures and visuals.
• For EAL learners, pair each word with a picture and allow home-language discussion before sharing in English. Give clear, one-step instructions and demonstrate thermometer and magnifying-glass use.
• For students requiring additional support, keep them close to the teacher during the investigation and provide a reduced choice of three planets before returning to all eight.
• Advanced learners create a temperature chart ranking all eight planets from hottest to coldest in the simplified distance model, then discuss why the real ranking is not determined by distance alone. They may add a labelled explanation of Venus’s atmosphere and Mercury’s very hot daytime surface.