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Stars as Light Sources Reflected Light from Planets Artificial Satellites Space Probes and Space Exploration Light Year (introductory use only)
Year 8 • Physics
Stars, Planets & Space Exploration
This lesson explains why stars produce their own light, why planets reflect light, how artificial satellites and space probes work, and how scientists measure vast distances in space using light years.
Lesson Objectives
- Understand stars as natural light sources.
- Explain reflected light from planets.
- Describe artificial satellites.
- Understand space probes and exploration.
- Use light year as a unit of distance (introductory).
1. Stars as Light Sources
Stars are massive balls of hot gas that produce their own light and heat.
They shine because of nuclear reactions happening in their cores.
[ Image Placeholder – Stars in the Night Sky ]
• The Sun is a star
• Stars give off their own light
• Stars appear small because they are very far away
• Stars give off their own light
• Stars appear small because they are very far away
Curiosity:
When you see stars at night, you are seeing light that left them years ago.
2. Reflected Light from Planets
Planets do not produce their own light.
They are visible because they reflect light from the Sun.
[ Image Placeholder – Sunlight Reflecting from a Planet ]
• Planets shine by reflected sunlight
• The Moon also reflects sunlight
• Without the Sun, planets would be dark
• The Moon also reflects sunlight
• Without the Sun, planets would be dark
Real-life link:
The Moon looks bright at night but is not a light source.
3. Artificial Satellites
An artificial satellite is a human-made object that orbits Earth or another planet.
[ Image Placeholder – Artificial Satellite Orbiting Earth ]
Uses of satellites:
• Communication (TV, internet)
• Weather forecasting
• GPS navigation
• Earth observation
• Communication (TV, internet)
• Weather forecasting
• GPS navigation
• Earth observation
4. Space Probes and Space Exploration
Space probes are unmanned spacecraft sent to explore space.
They collect data and send it back to Earth.
[ Image Placeholder – Space Probe Exploring Space ]
• Can travel very far from Earth
• Safer than human missions
• Help us learn about planets and stars
• Safer than human missions
• Help us learn about planets and stars
Example:
Probes have visited Mars, Jupiter, and even outside the Solar System.
5. Light Year (Introductory)
A light year is a unit of distance, not time.
It is the distance light travels in one year.
[ Image Placeholder – Light Travelling Through Space ]
• Space distances are extremely large
• Kilometres are too small to use
• Light years help astronomers measure distances
• Kilometres are too small to use
• Light years help astronomers measure distances
Curiosity:
Some stars we see are thousands of light years away.
Practice Questions
A. Fill in the Blanks
- Stars produce their own __________.
- Planets shine by __________ light.
- The Sun is a __________.
- Satellites orbit the __________.
- A light year is a unit of __________.
B. True or False
- Planets are light sources.
- The Moon reflects sunlight.
- Artificial satellites are natural objects.
- Space probes carry humans.
- A light year measures distance.
C. Short Answer
- Why do stars shine?
- Why can we see planets?
- Give two uses of satellites.
- What is a space probe?
- Why do astronomers use light years?
D. Thinking Questions
- Why do stars twinkle but planets usually do not?
- Why is the Sun important for life on Earth?
- Why are satellites useful for weather prediction?
- Why are space probes safer than human missions?
- Why does looking into space mean looking into the past?
✅ Show Answer Key
A. Fill in the Blanks
- light
- reflected
- star
- Earth
- distance
B. True or False
- False
- True
- False
- False
- True
C. Short Answer
- Because they produce energy in their cores.
- They reflect sunlight.
- Communication, weather (any two).
- An unmanned spacecraft.
- Because space distances are very large.
D. Thinking Questions
- Atmosphere affects star light.
- It provides light and heat.
- They observe clouds and storms.
- No risk to human life.
- Light takes time to travel.
© Aviate Learning – Stars & Space Exploration (Year 8)
🌟 Star vs 🪐 Planet Light Simulator
Use the switches to explore the difference between a star and a planet.
Observe which objects produce their own light and which only shine when light is reflected.
⭐ The star produces its own light.
🪐 The planet only shines when it reflects light from the Sun.
🌟 Star vs 🪐 Planet Light Simulator
Use the switches to explore the difference between a star and a planet.
Observe which objects produce their own light and which only shine when light is reflected.
⭐ The star produces its own light.
🪐 The planet only shines when it reflects light from the Sun.