Log inSign up for FREE
Library

4.05 The Effect of Gravitational Pull of the Moon and Sun on Earth

Last updated over 5 years ago
6 questions

4.05 The Effect of Gravitational Pull of the Moon and Sun on Earth



Gravity Review

Gravity is a force that tries to pull two objects toward each other.

Anything which has mass also has a gravitational pull. The more massive an object is, the stronger its gravitational pull is. Earth's gravity is what keeps you on the ground and what causes objects to fall. Gravity is what holds the planets in orbit around the Sun and what keeps the Moon in orbit around Earth. Distance also influences the amount of gravity on an object. The closer you are to an object, the stronger its gravitational pull is. Gravity is what gives you weight. It is the force that pulls on all of the mass in your body.

The Moon and Sun Review
Gravity keeps water on the Earth's surface. The moon is so large and close enough (mass and distance) that it's gravitational force has a noticeable effect on large bodies of water on Earth. The sun also exerts a gravitational force on the earth,.

Today's Directions: In this lesson, we will explore how the moon and the sun affect the gravity of Earth. Answer the pre-check question then watch the video to answer the following questions below.
1

What is happening in these images? Type your answer below.

Tide Activity!

Use this video to draw below. After completing this activity, you will receive a code for extra credit.

1

Do we have permission to share your artwork during class?

1

Drawing #1 - Click "Show Your Work" to begin drawing
- Draw a picture of the moon and the earth.
- Add detail to show how the moon's gravity affects the large bodies of water on Earth.
- Label areas of high tide.
(video minute 0:47)

1

Drawing #2 - Click "Show Your Work" to begin drawing
- Draw a beach at high tide in the left box and low tide on the right box.
Be creative!

1

Drawing #3 - Click "Show Your Work" to begin drawing
- Draw the sun, earth, and moon during spring tide.
- Label the high tide(s).
(video minute: 1:54)

1

Drawing #4 - Click "Show Your Work" to begin drawing
- Draw the sun, earth, and moon during neap tide.
- Label the high tide(s).
(video minute: 2:02)

What if the Moon didn’t exist?

Why a small silvery-looking sphere orbiting 384,400 kilometers away has a profound impact on us here on Earth

If the Moon were to suddenly vanish like in a sci-fi movie, our nights wouldn’t just be darker, our world would be radically changed – though at first, it would be hard to spot the difference. The most immediate effects of a post-Moon world would be small.

Although the lack of eclipses of any kind would be a sad loss, without the Moon’s glare, darker night skies would be great for anyone with a telescope.

For others, the outlook would not be so bright. Coral and certain species of crabs, worms, and fish can sense the moonlight from particular phases of the Moon. They use this as a trigger to start species-wide reproduction. How they would react to a permanently Moon-less night sky is unclear.

Tide times

A bigger instant effect would be on the ocean’s tides. Without the Moon dominating this picture, the Earth’s tides would be much simpler, but importantly much weaker.
📷


Turtles and surfers

With no strong tug from the Moon influencing the tides, animal life – particularly in the intertidal zone – would have to adapt fast. The intertidal zone is a concentrated band where certain species thrive between the ecological communities of the sea and the land. Weaker tides would cause this band to become narrower, increasing competition and jeopardizing survival.

Intertidal Zone

For example, the California grunion fish and various types of sea turtle would be lost if the Moon were to disappear, as they have evolved to be highly attuned to the rising and falling tides. They lay their eggs in the sand and time hatching to coincide with the tides that will give their offspring the best possible chance of survival. This system would break down without the Moon’s influence.

From a human point of view, weaker tides would make fishing for sea life that lives on or near the shore more difficult, as these marine animals move according to the movements of the tide. And it could also wipe out the sport of surfing. Though surfers rely on breaking waves for their fun – which are the result of how wind interacts with waves at the beach – they also follow the tide times avidly. This is because many surfers think that an incoming tide pushes more water towards the beach to make larger waves. Only recently were these surfers proved right about this phenomenon. So we now know that in a Moon-less world, big wave surfing would end.