The Moon and Its Phases
The Moon orbits Earth every 27 days and shows different phases as the amount of its lit side that we can see changes.
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The Moon orbits Earth every 27 days and shows different phases as the amount of its lit side that we can see changes.
- New moon to full moon takes about 29.5 days
- The Moon causes tides
- Eclipses happen when Sun, Earth and Moon align
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is The Moon and Its Phases?
Within Earth & Environmental Science, which covers our planet, its resources and ecosystems, and how people can protect the environment, this topic explains The Moon and Its Phases. Earth and environment topics show how the planet’s systems shape landscapes, climate and life, with models that make these processes visible.
Check that you can explain The Moon and Its Phases in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding The Moon and Its Phases helps you explain the environment around you and weigh up how people can protect it.
The Moon and Its Phases in detail
The Moon is Earth's only natural satellite, about a quarter of Earth's diameter, orbiting at about 384,000 km and taking about 27.3 days to circle us. It probably formed when a Mars-sized body hit the early Earth, and it has no atmosphere, with a surface of craters and dark plains (maria).
The Moon does not make its own light but reflects sunlight, and half of it is always lit. The phases, new moon, crescent, first quarter, gibbous, full and back, depend on how much of the lit half we can see from Earth as it orbits, with a cycle of about 29.5 days. The Moon's gravity causes the tides, and the same side always faces Earth.
How the interactive helps you understand The Moon and Its Phases
Watch the Earth model in the interactive. Use any sliders or buttons it offers to change the values and see how the Earth model responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of The Moon and Its Phases.
Real-life uses and examples
- Discuss how human activity changes The Moon and Its Phases, using a named example.
- Explain how The Moon and Its Phases affects the landscape or climate near you.
- Link The Moon and Its Phases to a real environmental problem and a possible solution.
Common mistakes to avoid
- Presenting one cause as the only cause of an environmental change.
- Describing a process without the timescale it works over.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about The Moon and Its Phases
What is The Moon and Its Phases?
The Moon orbits Earth every 27 days and shows different phases as the amount of its lit side that we can see changes.
What are the most important points about The Moon and Its Phases?
The main points are: New moon to full moon takes about 29.5 days; The Moon causes tides; Eclipses happen when Sun, Earth and Moon align.
Why is The Moon and Its Phases useful?
Understanding The Moon and Its Phases helps you explain the environment around you and weigh up how people can protect it.
How can I practise The Moon and Its Phases?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to The Moon and Its Phases?
Related topics in Earth & Environmental Science include Day, Night and Earth's Rotation, Space Exploration, Rocks and Minerals.