Chapter 19 Earth, Moon, and Sun

Bellwork Write about a scientific observation you made over the weekend. Don’t ask me, “What if I didn’t make one!”

How Earth Moves Earth moves through space in 2 major ways: 1: Rotation: the spinning of Earth on its axis Earth’s rotation causes day and night It takes Earth 24 hours to rotate once

Rotation 1037 miles/hr!

Why don’t we feel it? Our bodies are built to feel changes in speed, but not constant speed: – We can feel a car accelerating and decelerating, but not when it is moving at a constant speed.

Revolution 2: Revolution: the movement of one object around another One complete revolution around the sun is one year The path we follow around the sun is called our orbit – Slightly elongated circle, or ellipse

Revolution

Seasons on Earth Read page 662 and answer the following questions (with facts you find on this page) in your notebook: 1: Why is it warmer near the equator than near the poles? 2: If Earth’s axis were straight, how would our seasons differ? 3: Why does the Earth have seasons? 4: What are summer and winter caused by?

When you finish the questions Make your own illustration to show the Earth’s rotation, revolution, and the changing of seasons You may make one between you and your desk partner, or one on your own. Be creative, don’t over think it…

Section 2 Gravity and Motion

Gravity Actvity casis.org/Portals/0/education/lesson- plans/Gravity%20%E2%80%A6%20Depends%2 0on%20Where%20You%20Are.pdf casis.org/Portals/0/education/lesson- plans/Gravity%20%E2%80%A6%20Depends%2 0on%20Where%20You%20Are.pdf

Gravity A force is a push or a pull *in most cases forces deal with objects that are in contact with each other *Newton noticed that there was a force between heavenly bodies that were not in contact with each other

Gravity Newton and the apple: – When he saw the apple fall, he hypothesized that the force that pulled the apple to the ground was the same that pulled the moon around the Earth, and the Earth around the sun

Gravity Gravity: attracts all objects toward each other Law of Universal Gravitation: every object in the universe attracts every other object

Gravity The strength of force of gravity between two objects depends on two factors: – The masses of the objects – The distance between the objects

Gravity and Mass and Weight Everything exerts a gravitational force – You don’t feel the force of your book’s force because its mass is relatively small Gravitational force depends on mass – The greater the mass of an object, the greater the gravitational force

Gravity Mass and Weight Weight: the force of gravity on an object – Your mass never changes, but your weight can – Your weight on the moon is 1/6 what it is on Earth, why? – The moon is far less massive than the Earth, so its gravitational pull on you is less than that of the Earth

Gravity and Distance The force of gravity decreases rapidly as distance increases If the distance doubles, the force decreases to ¼ of its original force

Review What is a force? Does a force have to be between objects in contact? What is gravity? What is the Law of Universal Gravitation? Why is it universal? What two things does gravitational force depend on?

How does gravitational force depend on mass? How does gravitational force depend on distance? How are mass and weight different?

Bellwork In your own words, explain how gravitational force depends on mass

Inertia and Orbital Motion Inertia is the reason the Earth doesn’t fall into the sun and the moon doesn’t crash into the Earth Inertia: the tendency of an object to resist a change in motion Inertia is the reason you need seatbelts!

Inertia and Orbital Motion Newton’s First Law of Motion: an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted upon by an outside force

Orbital Motion Gravity plus inertia keep heavenly bodies in orbital motion

Section 3 Phases, Eclipses, and Tides

Motions of the Moon The changing positions of the Earth, moon, and sun cause the phases of the moon, eclipses, and tides

Motions of the Moon The moon’s rotation and revolution take the same amount of time So, a “day” and a “year” on the moon are the same Thus, the same side of the moon is always facing the Earth

Phases The light of the moon is the sun’s light reflected off the moon’s surface Phases: are the different shapes of the moon The phase we see depends on how much of the sunlit side of the moon faces Earth

Phases of the Moon

Moon’s Rotation and Revolution

Phases of the Moon 9Xc 9Xc

Eclipses eDA eDA

Eclipses Because of the tilt of the moon’s orbit around Earth, both the Earth and moon create shadows When the moon’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs

Solar and Lunar Eclipses

Graphic Organizer Make a book about solar and lunar eclipses Follow the below directions for both solar and lunar eclipses – Explain how the eclipse occurs (sentence is in bold) – During what phase of the moon does the eclipse occur – Summarize both the total and partial eclipses for both – Draw a diagram for a solar and lunar eclipse

Eclipse Concepts A solar eclipse occurs when the moon passes directly between Earth and the sun, blocking sunlight from Earth They occur during a new moon

Eclipse Concepts The geometry of the sun’s rays and the position of the Earth, moon, and sun create two views of an eclipse. People on Earth within the “umbra,” or the moon’s darkest shadow, experience a total eclipse. Here the light from the sun is completely blocked

Total Eclipse GUyw GUyw

Total Eclipse

Partial Solar Eclipse Summarize a partial solar eclipse During a partial solar eclipse, the larger part of the sun’s shadow is less dark than the umbra. This shadow is called the penumbra. Here part of the sun is visible, unlike the total solar eclipse.

Partial Solar Eclipse

Review of Book Continued When do lunar eclipses occur? During a lunar eclipse, the Earth blocks sunlight from reaching the moon. They occur during a full moon

Summarize a total lunar eclipse A total lunar eclipse is like a total solar eclipse. You only see the edge of Earth’s shadow on the moon. Unlike total solar eclipses, total lunar eclipses are visible everywhere the moon is visible

Total Lunar Eclipse

Summarize a partial lunar eclipse: Most lunar eclipses are partial and the Earth, sun, and moon don’t line up perfectly.

Partial Lunar Eclipse

Tides FBI FBI

Tides Tides: the rise and fall of ocean water every 12.5 hours or so. At any one time there are two places with high tides and two places with low tides on Earth. High tide is always facing the moon and on the opposite side of the Earth Low tide is at either point of Earth between high tides

Tides

Spring Tides During a new moon and full moon the sun, moon, and Earth are nearly in a line Due to this, the moon and sun’s gravitational forces are pulling on Earth’s waters in opposite directions This gives the oceans a higher tide than otherwise; known as the spring tide

Neap Tides Between spring tides (during moon’s first and third quarter phases) the line between the sun and Earth is a right angle This causes less gravitational pull on the water and a lower tide; known as a neap tide