Earth and Moon Lesson: Rotation, Revolution, Tides & Phases

Lesson Overview

• The Earth's Movements
• Earth's Axis and the Seasons
• The Moon and Its Motion
• Moon Phases: Why the Moon Looks Different
• Tides: How the Moon Affects Water
• Eclipses: Shadows in Space
• Comparing Earth, Moon, and Sun
• Light and Shadows

Have you ever wondered why we have day and night, why the Moon looks different each week, or why the ocean water moves in and out? These amazing changes happen because of the relationship between Earth and its closest neighbor, the Moon. Understanding how Earth and Moon move and affect each other helps explain many things we see every day.

The Earth's Movements

What Is Rotation?

Rotation means to spin. Earth spins around an invisible line called an axis, which goes from the North Pole to the South Pole. This spinning is what gives us day and night. One full rotation takes about 24 hours, or one day.

• When your part of Earth faces the Sun, it's daytime.
• When your part turns away from the Sun, it's nighttime.

Sunrise and Sunset: As the Earth rotates, the Sun appears to rise in the east and set in the west. When we say the Sun is setting, we really mean that our part of Earth is turning away from the Sun.

What is Revolution?

Revolution means to travel around something. Earth moves in a path around the Sun, and this path is called an orbit. One full orbit takes about 365 days, or 1 year.

• While rotating daily, Earth also travels around the Sun yearly.

Earth's Axis and the Seasons

Earth's axis is tilted about 23.5 degrees, not straight up and down. This tilt, along with Earth's revolution, causes the seasons.

• When the Northern Hemisphere is tilted toward the Sun: Summer.
• When it is tilted away: Winter.

Seasons in the Southern Hemisphere

When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere. This is because the Sun's rays hit the two hemispheres differently due to Earth's tilt.

Winter Solstice: Around December 21st, the most direct Sun rays hit 23.5° south (Tropic of Capricorn). This means more daylight and heat in the Southern Hemisphere, and shorter days in the Northern Hemisphere (like in Alaska).

The Moon and Its Motion

The Moon is Earth's only natural satellite. It orbits the Earth and takes about 28 days to complete one trip.

• This orbit is what causes the phases of the Moon.

Moon Phases: Why the Moon Looks Different

As the Moon orbits Earth, we see different parts of its sunlit side. These are called phases:

• New Moon – Moon is between Earth and Sun; we can't see it.
• Waxing Crescent – A lit sliver on the right side.
• First Quarter – Right half is visible.
• Full Moon – Fully visible.
• Waning Gibbous – Less than full but more than half.
• Third Quarter – Left half visible.
• Waning Crescent – A thin lit sliver on the left.

Tides: How the Moon Affects Water

The Moon's gravity pulls on Earth's oceans, causing tides-the rise and fall of sea levels.

• Spring Tides: Happen during New and Full Moons when Sun, Moon, and Earth are in a straight line. Result: very high and low tides.
• Neap Tides: Happen when Sun, Moon, and Earth are at right angles (during First and Third Quarters). Result: less extreme tides.

Eclipses: Shadows in Space

Lunar Eclipse:

Earth blocks sunlight from reaching the Moon. This can only happen during a Full Moon. The Moon may appear reddish.

Solar Eclipse:

Moon blocks sunlight from reaching part of Earth. Happens only during a New Moon.

Comparing Earth, Moon, and Sun

Light and Shadows

How is a shadow made?
A shadow is formed when an object blocks light from reaching a surface.

• If you stand in front of a light source (like the Sun), your body blocks the light and casts a shadow.
• This shows that light travels in straight lines and can be blocked.

The Earth and Moon are partners in a cosmic dance. The Earth spins and orbits the Sun, giving us day, night, and seasons. The Moon orbits Earth and changes how it looks to us through phases, and even controls the tides. Their interaction also creates eclipses and beautiful patterns in nature. When you understand these concepts, you're not just ready for a quiz-you're understanding the rhythms of our planet!