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Post by momof6 on Dec 2, 2004 17:39:35 GMT -5
What a wonderful planet we live on  |
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Post by momof6 on Dec 2, 2004 17:46:52 GMT -5
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Post by momof6 on Dec 2, 2004 17:52:51 GMT -5
Planet Report
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Name __________________ Date ___________________
Name of Planet ________________________
Position from the sun ____________________
Report:
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What was the most interesting fact you researched about your planet?
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Post by momof6 on Dec 2, 2004 17:58:31 GMT -5
INTRODUCTION TO THE EARTH
The Earth is the third planet from the Sun in our Solar System. It is the planet we were created on and the only planet in our Solar System that is known to support life.
SIZE
The Earth is about 7,926 miles (12,756 km) in diameter. The Earth is the fifth-largest planet in our Solar System (after Jupiter, Saturn, Uranus, and Neptune).
Eratosthenes (276-194 BC) was a Greek scholar who was the first person to determine the circumference of the Earth. He compared the midsummer's noon shadow in deep wells in Syene (now Aswan on the Nile in Egypt) and Alexandria. He properly assumed that the Sun's rays are virtually parallel (since the Sun is so far away). Knowing the distance between the two locations, he calculated the circumference of the Earth to be 250,000 stadia. Exactly how long a stadia is is unknown, so his accuracy is uncertain, but he was very close. He also accurately measured the tilt of the Earth's axis and the distance to the sun and moon.
The Earth and the moon. Photo taken by NASA's Galileo mission in 1990.
THE MOON
The Earth has one moon. The diameter of the moon is about one quarter of the diameter of the Earth.
The moon may have once been a part of the Earth; it may have been broken off the Earth during a catastrophic collision of a huge body with the Earth billions of years ago.
MASS, DENSITY, AND ESCAPE VELOCITY
The Earth's mass is about 5.98 x 1024 kg.
The Earth has an average density of 5520 kg/m3 (water has a density of 1027 kg/m3). Earth is the densest planet in our Solar System.
To escape the Earth's gravitational pull, an object must reach a velocity of 24,840 miles per hour (11,180 m/sec).
LENGTH OF A DAY AND YEAR ON EARTH
Earth rising over the moon. Photo taken by NASA's Apollo 8 mission.
Each day on Earth takes 23.93 hours (that is, it takes the Earth 23.93 hours to rotate around its axis once - this is a sidereal day). Each year on Earth takes 365.26 Earth days (that is, it takes the Earth 365.26 days to orbit the Sun once).
The Earth's rotation is slowing down very slightly over time, about one second every 10 years.
THE EARTH'S ORBIT
Planet-Sun Orbital Diagram
Label the aphelion (farthest point in orbit) and perihelion (closest point in orbit) of a planet in orbit.
Answers
The Earth orbits, on average, 93 million miles (149,600,000 km) from the Sun. This distance is defined as one Astronomical Unit (AU). The Earth is closest to the Sun (this is called perihelion) around January 2 each year (91.4 million miles = 147.1 million km); it is farthest away from the Sun (this is called aphelion) around July 2 each year (94.8 million miles = 152.6 million km).
Orbital Eccentricity
The Earth' orbital eccentricity is 0.017; it has an orbit that is close to being circular.
THE EARTH'S AXIS TILT AND THE SEASONS
The Earth's axis is tilted from perpendicular to the plane of the ecliptic by 23.45°. This tilting is what gives us the four seasons of the year: Summer, Spring, Winter and Autumn. Since the axis is tilted, different parts of the globe are oriented towards the Sun at different times of the year. This affects the amount of sunlight each receives.
SPEED
At the equator, the Earth's surface moves 40,000 kilometers in 24 hours. That is a speed of about 1040 miles/hr (1670 km/hr). This is calculated by dividing the circumference of the Earth at the equator (about 24,900 miles or 40,070 km) by the number of hours in a day (24). As you move toward either pole, this speed decreases to almost zero (since the circumference at the extreme latitudes approaches zero).
The Earth revolves around the Sun at a speed of about 30 km/sec. This compares with the Earth's rotational speed of approximately 0.5 km/sec (at middle latitudes - near the equator).
The size of the atmosphere in this illustration is greatly exaggerated in order to show the greenhouse effect. The Earth's atmosphere is about 300 miles (480 km) thick, but most of the Earth's atmosphere is within 10 miles (16 km) of the Earth's surface.
TEMPERATURE ON EARTH
The temperature on Earth ranges from between -127°F to 136°F (-88°C to 58°C; 185 K to 311 K). The coldest recorded temperature was on the continent of Antarctica (Vostok in July, 1983). The hottest recorded temperature was on the continent of Africa (Libya in September, 1922).
The greenhouse effect traps heat in our atmosphere. The atmosphere lets some infrared radiation escape into space; some is reflected back to the planet.
ATMOSPHERE
The Earth's atmosphere is a thin layer of gases that surrounds the Earth. It is composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases.
The atmosphere was formed by planetary degassing, a process in which gases like carbon dioxide, water vapor, sulphur dioxide and nitrogen were released from the interior of the Earth from volcanoes and other processes. Life forms on Earth have modified the composition of the atmosphere since their evolution.
(written with an evolution point of view)
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Post by momof6 on Dec 2, 2004 18:04:05 GMT -5
Use the section on the Earth to answer the following questions.
1. How long does it take the Earth to revolve around the Sun? ____________________
2. How far is the Earth from the Sun?_______________________
3. Is the Earth's orbit around the Sun highly elliptical or almost circular?_______________________
4. The Earth is the densest planet in the Solar System. Is it denser or less dense than water?_______________________
5. It the Earth's rotation slowing down or speeding up slightly over time? _____________________
6. What is the core of the Earth made of? _______________________
7. What is the major component of the Earth's atmosphere? ______________________
8. What is the name of the lowest layer of the Earth's atmosphere? This is the layer in which weather occurs. _______________________
9. Are the seasons on Earth caused by the tilt of the Earth's axis or the fact that the Earth's distance from the Sun varies throughout the year? ______________________
10. Is the Earth double, four times, or eight times larger (in diameter) than the Moon? ______________________
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Post by momof6 on Dec 2, 2004 18:13:24 GMT -5
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Post by momof6 on Dec 2, 2004 18:17:31 GMT -5
Earth
By Sharon Fabian
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1 People have always known about planet Earth. Even the most ancient people knew about Earth. It was what they slept on every night. The trees that they took shelter under grew from the earth. Earth provided plants for their food and animals for them to hunt.
2 There is one thing that these ancient people didn't know about Earth; they didn't know that Earth is a planet. If someone had told them that Earth floats in space and revolves around the sun, they probably would have just looked at that person like he was crazy.
3 Common sense told people that Earth was at the center of the universe and that it was standing still. After all, no one could see it move, and no one could feel it move. From all appearances, Earth stood still while other objects in the sky moved around it. Everyone could see that the sun rose in the east every morning and set in the west every evening. The moon traveled across the sky too. Even some stars changed their position in the sky.
4 Another nice thing about the earth was that it was flat. No one had to worry about falling off the Earth, as they would if they lived on something round like the moon.
5 By the time of the ancient Greeks, there was some disagreement about all of this, but a famous scientist, Ptolemy, provided the most convincing theory. Ptolemy's theory said that the earth was the center of the universe, and that is what most people continued to believe.
6 One person who disagreed was Nicolaus Copernicus. Copernicus was an astronomer who lived from 1473 to 1543. He had his own theory about the earth, and he was certain that he was right. Copernicus's theory was that the earth, like all of the other planets, revolves around the sun. He also suggested that the earth rotates on its axis once every day. He couldn't prove his theories, but he used math to show that they were likely to be right. He explained his theories in his book, On the Revolution of the Heavenly Spheres.
7 In the meantime, many people continued to believe that the earth was the center of the universe. In churches, people learned that this is what they should believe.
8 At the same time too, scientists kept looking for proof. In Italy, Galileo used the new science of physics to try to prove Copernicus's theory. In Germany, Johannes Kepler studied the same problem. Both scientists developed evidence that showed that Copernicus's theory was correct. At the time, people did not want to believe them, but today we know that Copernicus was right.
9 Still, it is easy to see why people wanted to believe that Earth is the center of the universe. Earth is certainly the most important planet to every one of us. Earth is a unique place. It is the only planet with an atmosphere that provides oxygen to breathe and at the same times protects us from the sun's radiation. It is the only planet with oceans and seas, rivers and streams, and rain. It's the only planet with green plants to produce the oxygen for us to breathe and food for us to eat. It's the only planet with insects, and birds, and fish, and animals. It's the only planet with people. So it's no wonder that the earth seems like the center of the universe. In most ways, to the people who live on Earth, Earth is the center. It's the only place to be. But in another more scientific way, Earth is only one little planet revolving around the sun, along with at least eight other planets.
10 Then there are all of the other suns in the universe. Many of them have systems of planets revolving around them too. Maybe in one of those systems somewhere, there is another planet with all of the good things -- a planet that seems like the center of the universe to its inhabitants.
Copyright © 2004 edHelper
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Name _____________________________
Date ___________________
Earth
1. Copernicus's theory was that the _____.
Earth revolves around the sun
Sun revolves around the earth
Moon revolves around the sun
None of the above
2. Galileo and Kepler _____.
Developed proof for Copernicus's theory
Proved Copernicus wrong
Proved Ptolemy's theory
None of the above
3. Who came first?
Copernicus
Ptolemy
Galileo
Kepler
4. To many people, Earth seemed like the center of the universe because _____.
The sun and the moon appeared to move around the earth
It was home
It provided everything people needed
All of the above
5. There are _____ planets in the universe.
Many
One thousand
Eight
Nine
6. Copernicus's book is called On the Revolution of the Heavenly Spheres. We can infer that the word spheres in the title means _____.
Suns
Moons
Comets
Round objects in the sky such as planets and stars
7. The main idea of this article is _____.
Copernicus
The amount of time it takes Earth to rotate on its axis
Comparing Earth to the other planets
Earth as the center of the universe
8. When scientists talked about the center of the universe, they meant the point that everything else revolved around. When other people say that Earth still seems like the center, they mean that Earth is the _____.
Most important to them
Largest
Roundest
Fastest
Earth - Answer Key
1 Earth revolves around the sun
2 Developed proof for Copernicus's theory
3 Ptolemy
4 All of the above
5 Many
6 Round objects in the sky such as planets and stars
7 Earth as the center of the universe
8 Most important to them
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Post by momof6 on Dec 2, 2004 18:19:41 GMT -5
Name _____________________________
Date ___________________
Earth Word Search
Find each of the following words.
SUMMER
CIRCULAR ORBIT
OCEANS
ARTIFICIAL SATELLITES
GREENHOUSE EFFECT
DENSEST PLANET
OUTER CORE
EARTH
ARGON
THIRD PLANET
24 HOURS ROTATION
FOUR SEASONS
CONTINENTS
SPRING
AUTUMN
LIFE
ATMOSPHERE
NITROGEN
WINTER
INNER CORE
CRUST
MANTLE
IRON
TILTED AXIS
OXYGEN
THINK ATMOSPHERE
L I F E U T A R T I F I C I A L S A T E L L I T E S O R T
C E N I T R O G E N M R E L M A N T L E T H 2 I R O N T
O A G A E S T C R G R E E N H O U S E E F F E C T P S R
N R C N E M N F A R G O N D E N S E S T P L A N E T R O
T T I R I N S C I R C U L A R O R B I T R N N O N U F U
I H O R U R O U S N I I N N E R C O R E C I M N M N T T
N E E C E S P C M T I L T E D A X I S X I S U I T S F N
E N T E E T T S D M T H I R D P L A N E T N T N T O A E
N T S O N A N O U T E R C O R E A N R F O U U N R R I
T L S S N N I O M N R E G I C F O U R S E A S O N S
S C O H A R I S W T H I N K A T M O S P H E R E F C T E
U D 2 4 H O U R S R O T A T I O N E G Y X O S A N P E
E M I N T N U R C R D F T R E C R M E I A G O N T A
Answer Key
SUMMER CIRCULAR ORBIT OCEANS ARTIFICIAL SATELLITES
GREENHOUSE EFFECT DENSEST PLANET OUTER CORE EARTH
ARGON THIRD PLANET 24 HOURS ROTATION FOUR SEASONS
CONTINENTS SPRING AUTUMN LIFE
ATMOSPHERE NITROGEN WINTER INNER CORE
CRUST MANTLE IRON TILTED AXIS
OXYGEN THINK ATMOSPHERE
L I F E A R T I F I C I A L S A T E L L I T E S
C E N I T R O G E N M A N T L E I R O N
O A G G R E E N H O U S E E F F E C T
N R C N A R G O N D E N S E S T P L A N E T
T T R I S C I R C U L A R O R B I T N
I H O R U R U I N N E R C O R E M
N C E S P M T I L T E D A X I S U
E E T T S M T H I R D P L A N E T T
N A N O U T E R C O R E U
T N I R F O U R S E A S O N S
S S W T H I N K A T M O S P H E R E
2 4 H O U R S R O T A T I O N E G Y X O
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Post by momof6 on Dec 2, 2004 18:33:00 GMT -5
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