How long does the Earth take to orbit the Sun?

About 365¼ days, which is one year.

Which way does the Earth rotate?

From west to east, so the Sun appears to rise in the east.

What causes the seasons?

The 23.5° tilt of the Earth's axis as it orbits the Sun.

Why is it summer when a hemisphere is tilted towards the Sun?

The Sun is higher in the sky, sunlight is more concentrated and days are longer.

Does the Earth's distance from the Sun cause the seasons?

No. The distance changes very little. The tilt is the cause.

What causes the phases of the Moon?

We see different amounts of the Moon's lit half as it orbits the Earth.

Where is the Moon at new Moon?

Between the Earth and the Sun, with its lit half facing away from the Earth.

When does a solar eclipse happen?

When the Moon passes between the Sun and the Earth, at new Moon.

When does a lunar eclipse happen?

When the Earth is between the Sun and the Moon and its shadow falls on the Moon, at full Moon.

Why do eclipses not happen every month?

The Moon's orbit is tilted slightly, so the Sun, Earth and Moon are not usually exactly in line.

What mainly causes tides?

The gravitational pull of the Moon (and the Sun) on the oceans.

When are tidal ranges biggest?

At new Moon and full Moon, when the Sun, Earth and Moon are in line.

The Earth, Moon and SunIB MYP Physics: Flashcards

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What causes day and night?

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What causes day and night?: The Earth rotating on its axis once every 24 hours.
How long does the Earth take to orbit the Sun?: About 365¼ days, which is one year.
Which way does the Earth rotate?: From west to east, so the Sun appears to rise in the east.
What causes the seasons?: The 23.5° tilt of the Earth's axis as it orbits the Sun.
Why is it summer when a hemisphere is tilted towards the Sun?: The Sun is higher in the sky, sunlight is more concentrated and days are longer.
Does the Earth's distance from the Sun cause the seasons?: No. The distance changes very little. The tilt is the cause.
Does the Moon make its own light?: No. It reflects sunlight.
What causes the phases of the Moon?: We see different amounts of the Moon's lit half as it orbits the Earth.
Where is the Moon at new Moon?: Between the Earth and the Sun, with its lit half facing away from the Earth.
When does a solar eclipse happen?: When the Moon passes between the Sun and the Earth, at new Moon.
When does a lunar eclipse happen?: When the Earth is between the Sun and the Moon and its shadow falls on the Moon, at full Moon.
Why do eclipses not happen every month?: The Moon's orbit is tilted slightly, so the Sun, Earth and Moon are not usually exactly in line.
What mainly causes tides?: The gravitational pull of the Moon (and the Sun) on the oceans.
When are tidal ranges biggest?: At new Moon and full Moon, when the Sun, Earth and Moon are in line.

Exam questions on The Earth, Moon and Sun

A student in Reykjavik, Iceland, notices that in June the Sun stays above the horizon for about 21 hours each day, but in December it is up for only about 4 hours. Reykjavik is in the northern hemisphere.
Explain why Reykjavik has much more daylight in June than in December.2 marks
Astronomers at an observatory in Chile record the appearance of the Moon every night. Over about 29.5 days its visible shape changes from a thin crescent to a full circle and back again. They also note that half of the Moon is always lit by the Sun.
Explain why half of the Moon is always lit but the shape we see changes over the month.2 marks
A total solar eclipse is predicted to cross parts of Indonesia. About two weeks later, a total lunar eclipse will be visible across Africa and Europe. Eclipses do not happen every month, even though the Moon orbits the Earth about once a month.
Describe how a solar eclipse happens.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).