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Moon and Tides

In this presentation you will: explore the Moon and the effects it has on Earth

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Introduction

The Moon orbits the Earth.

Earth Moon orbit

It is about a quarter of the size of the Earth.

The Moon is important to life on Earth as it affects the tides in the oceans. Next >

The Moon

The Moon also spins on its own axis.

It takes 28 days for the Moon to orbit the Earth. Earth

Moon orbit

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This means that from Earth we always see the same side of the Moon.

This also takes 28 days.

Phases of the Moon

Our view of the Moon is continuously changing.

This is because

It can appear circular, crescent shaped, or may not be visible at all.

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This is because the Sun only lights the side of the Moon that faces it.

We only see the part of the Moon that is lit by the Sun.

Tides

Tides are the rising and falling of the Earth’s oceans.

They are caused by the gravitational gforces from the Moon and the Sun.

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The difference between the height of the water between high and low tide is called tidal range.

Tides

The Sun is much bigger than the Moon, yet the tides are affected more by the Moon.

Approx. 380 thousand kilometers(240 thousand miles)

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Approx. 150 million kilometers(94 million miles)

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Which of the following statements is true?

Question 1

A) The Earth’s tides are affected only by the Moon.

B) The Earth’s tides are affected only by the Sun.

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C) The Earth’s tides are affected by the Earth’s rotation.

D) The Earth’s tides are affected by both the Sun and the Moon.

Which of the following statements is true?

Question 1

A) The Earth’s tides are affected only by the Moon.

B) The Earth’s tides are affected only by the Sun.

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) y y

C) The Earth’s tides are affected by the Earth’s rotation.

D) The Earth’s tides are affected by both the Sun and the Moon.

High Tides and Low Tides

The gravitational force of the Moon on the Earth pulls the water toward the Moon.

This causes high tide on the side closest to the Moon.

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High Tides and Low Tides

You might expect therefore that low tide is on the other side of the Earth, but this is not the case.In actual fact, the opposite side of the Earth also experiences high tide.

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This is because the water furthest from the Moon experiences less gravity, and so it bulges away from the Moon.

High Tides and Low Tides

Each ocean will experience a high tide approximately every 12.5 hours.

In between high tides, there are low tidesthere are low tides.

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These occur as the water in the ocean is pulled away by a high tide elsewhere.

If a certain point has a high tide at 9.00 am, approximately what time will the next high tide be?

Question 2

A) 12.30 pm

B) 9.00 pm

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C) 9.30 pm

D) 9.00 am the next day

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If a certain point has a high tide at 9.00 am, approximately what time will the next high tide be?

Question 2

A) 12.30 pm

B) 9.00 pm

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C) 9.30 pm

D) 9.00 am the next day

Low tide is experienced at the point on Earth furthest from the Moon.

Is this statement true or false?

Question 3

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Answer True or False.

Low tide is experienced at the point on Earth furthest from the Moon.

Is this statement true or false?

Question 3

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Answer True or False.False

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The Sun’s Influence

The Sun’s gravitational pull also affects the Earth’s tides.

It is not as influential as the Moon, however it does give some noticeable effects.

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Spring Tides

When the Sun and the Moon are in line with the Earth, the gravitational forces combine to be stronger.

This causes aspring tide Earth

Sun

spring tide.

This is when the high tide is at its highest.

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There is no connection between spring tides and the season of Spring.

Moon

Earth

extra gravitational pull

spring tide

Neap Tides

When the Sun and the Moon are at right angles, the gravitational pull of the Sun partially cancels out that of the Moon.

Earth

Sun

This causes aneap tide.

This is when the high tide is at its lowest. Next >

Moon

The gravitational pull from the Sun is

working against the gravitational pull from the Moon.

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What is it called when high tide is at its highest?

Question 4

A) Spring Tide

B) Summer Tide

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C) Fall Tide

D) Winter Tide

What is it called when high tide is at its highest?

Question 4

A) Spring Tide

B) Summer Tide

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C) Fall Tide

D) Winter Tide

Eclipse

When the Sun, the Moon and the Earth line up directly we experience an eclipse.

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When this happens, we experience spring tides, although they are no bigger than normal spring tides.

Courtesy NASA

Lunar Eclipse

When the Moon is directly behind the Earth, we cannot see it as the Sun’s light is blocked.

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This is called a lunar eclipse.

Solar Eclipse

When the Moon is directly in front of the Sun, we cannot see the Sun from the Earth.

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This is called a solar eclipse.

Courtesy NASA

Ross says that when we experience a solar eclipse there is a spring tide. Andy says that when we experience a lunar eclipse there is a neap tide.

Who is correct?

Question 5

A) Ross only

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A) Ross only

B) Andy only

C) Both Ross and Andy

D) Neither Ross nor Andy

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Ross says that when we experience a solar eclipse there is a spring tide. Andy says that when we experience a lunar eclipse there is a neap tide.

Who is correct?

Question 5

A) Ross only

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A) Ross only

B) Andy only

C) Both Ross and Andy

D) Neither Ross nor Andy

Summary

the main characteristics of the Moon

In this presentation you have seen:

how the Moon and the Sun affect tides on Earth

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