Daylight Hours and The Phases of the Moon

Daylight Hours

There are two main ways that the Earth's tilt causes differences in temperature in different seasons.

The Earth's tilt changes:

• how directly the Sun's rays hit the Earth, and

• how many hours of daylight there are.

Daylight Hours

Have you ever noticed that the Sun rises and sets at different times in summer and winter? The number of daylight hours you experience depends on the time of year and how far north or south of the Equator you are.

The location marked by a white dot in the diagram is on the Equator. As the Earth rotates on its axis each day, this location spends:

• half of its time in sunlight, or daytime (shown in red)

• half of its time in darkness, or night-time (shown in blue)

This means that days and nights are both 12 hours long.

On the Equator, days and nights are the same length throughout the year. But if you move further north or south, it's a different story!

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Now imagine two locations that are equal distances north and south of the Equator. In the diagram, these points are labelled A and C.

When it's summer in the northern hemisphere, more of that hemisphere gets bathed in sunlight. So Location A spends more than half of its time in the sunlight as Earth rotates. This is shown in red. This means that daylight hours are longer in summer.

Location A spends less than half of its time in darkness each day. This is shown in blue. This means that nights are shorter in summer.

The Important bits...

Copy these into your Science books.

• Effect of Earth's Tilt:

  • The Earth’s tilt causes changes in the length of day and night throughout the year.

  • At the Equator, days and nights are always equal (12 hours each).

The Important bits...

Copy these into your Science books.

• Daylight Changes with Latitude:

  • As you move away from the Equator, the number of daylight hours changes with the seasons.

  • In summer, locations in one hemisphere get more daylight, while in winter, they get less.

  • At the Poles, there can be 24 hours of daylight in summer and 24 hours of darkness in winter.

The Important bits...

Copy these into your Science books.

• Link to Seasons:

  • The variation in daylight hours influences seasonal temperatures: more daylight in summer leads to warmer temperatures.

Phases of the Moon

Getting to know the moon

For thousands of years, humans have gazed at the sky and wondered about the Moon. But have you ever wondered what it would be like to be on its surface?

In 2013, China sent an unmanned rover called Yutu to explore the Moon's surface. The images it captured allow you to imagine visiting the Moon for yourself!

Image taken from the Rover in 2013

Observing the moon

Long before humans landed on the Moon, we were observing it from Earth. In 1609, the Italian scientist Galileo Galilei invented one of the first telescopes. At the time, most people thought the Moon was a smooth sphere. But using his telescope, Galileo discovered that the surface had craters, mountains and valleys.

New technologies and more powerful telescopes have continued to expand our knowledge of the Moon. The first photos of the far side of the Moon were taken in 1959 and astronauts landed on its surface in 1969. 

The Phases of the moon

When you look up at the Moon, night after night, it appears to slowly change shape. Sometimes you'll see a full moon and sometimes only a thin sliver. There are times when you can't see the Moon at all. These different shapes of the Moon are called phases.

The Phases of the moon

Record these into your books

Draw the following diagram into your books

the important bits

write these summary notes into your books

• Phases of the Moon:

  • The Moon goes through different phases as it orbits the Earth, taking 29.5 days to complete a cycle.

the important bits

write these summary notes into your books

• Phases of the Moon:

  • The main phases are:

    • New Moon: Moon is between Earth and the Sun, and the side facing Earth is dark.

    • First Quarter: Half of the Moon is visible from Earth.

    • Full Moon: Earth is between the Moon and the Sun; the entire face of the Moon is lit.

    • Third Quarter: Again, half of the Moon is visible, but the opposite half compared to the First Quarter.

the important bits

write these summary notes into your books

• Why Phases Occur:

  • The phases happen because as the Moon orbits Earth, we see different amounts of its sunlit side.

  • We always see the same side of the Moon because it rotates once for every orbit around Earth.

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