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The Power of the SunBy Kimberly DumkeFriday, January 21, 2011The sun is the closest star to Earth. Even at a distance of 150 million kilometers (93 million miles), its gravitational pull holds the planet in orbit. It radiates light and heat, or solar energy, which makes it possible for life to exist on Earth.Plants need sunlight to grow. Animals, including humans, need plants for food and the oxygen they produce. Without heat from the sun, Earth would freeze. There would be no winds, ocean currents, or clouds to transport water.Solar energy has existed as long as the sun—about 5 billion years. While people have not been around that long, they have been using solar energy in a variety of ways for thousands of years.Solar energy is essential to agriculture—cultivating land, producing crops, and raising livestock. Developed about 10,000 years ago, agriculture had a key role in the rise of civilization. Solar techniques, such as crop rotation, increased harvests. Drying food using sun and wind prevented crops from spoiling. This surplus of food allowed for denser populations and structured societies.Early civilizations around the world positioned buildings to face south to gather heat and light. They used windows and skylights for the same reason, as well as to allow for air circulation. These are elements of solar architecture. Other aspects include using selective shading and choosing building materials with thermal mass, meaning they store heat, such as stone and concrete. Today, computer programs make applications easier and more precise.The greenhouse is another early solar development. By converting sunlight to heat, greenhouses make it possible to grow plants out of season and in climates that may not be suited for them. One of the earliest greenhouses dates to 30CE, before glass was even invented. Constructed from translucent sheets of mica, a thin mineral, it was built for the Roman emperor Tiberius, who wanted to be able to eat cucumbers all year. The general technique is the same today, although there have been many improvements to increase the variety and amount of crops grown.Once food is harvested, solar energy can be used to cook it. The first solar box cooker was built in 1767 by Horace de Saussure, a Swiss physicist. It reached temperatures of 87.8 degrees Celsius (190 degrees Fahrenheit) and was used to cook fruit. Today, there are many different types of solar cookers being used for cooking, drying and pasteurization, which slows the growth of microbes in food. Because they do not use fossil fuels, they are safe, do not produce pollution or cause deforestation.Solar cookers are used in many parts of the world in growing numbers. It is estimated that there are half a million installed in India alone. India has the world’s two largest solar cooking systems, which can prepare food for 25,000 people daily. According to Indian Prime Minister Manmohan Singh, “Since exhaustible energy sources in the country are limited, there is an urgent need to focus attention on development of renewable energy sources and use of energy efficient technologies.”In Nicaragua, a modified solar cooker is being used to sterilize medical equipment at clinics.Solar thermal energy can be used to heat water. First introduced in the late 1800s, the solar water heater was a big improvement over stoves that burned wood or coal because it was cleaner and cost less to operate. They were very popular for American homes in sunny places, including Arizona, Florida, and California. However, in the early 1900s, low-cost oil and natural gas became available and solar water systems began to be replaced. Today, they are not only popular again; they are becoming the norm in some countries, including China, Greece, and Japan. They are even required to be used in any new construction in Australia, Israel, and Spain.Besides heating water, solar energy can be used to make it potable, or suitable for drinking. One method is solar disinfection (SODIS). Developed in the 1980s, SODIS involves filling plastic soda bottles with water then exposing them to sunlight for several hours. This process reduces the viruses, bacteria and protozoa in water. More than 2 million people in 28 developing nations use this method daily for their drinking water.Solar power—the conversion of sunlight into electricity—is yet another application of solar technology. This can be done in a number of ways. The two most common are photovoltaic (solar cells) and concentrating solar power.Solar cells convert sunlight directly into electricity. The amount of power generated by each cell is very low. Therefore, large numbers of cells must be grouped together, like the panels mounted on the roof of a house, to generate enough power.The first solar cell was constructed in the 1880s. The earliest major application was on the American satellite Vanguard I, launched in 1958. A radio transmitter powered by solar cells operated for about seven years; one using conventional batteries lasted only 20 days. Since then, solar cells have become the established power source for satellites, including those used in the telecommunications industry.On Earth, solar cells are used for everything from calculators and watches to homes, commercial buildings, and even stadiums. Kaohsiung World Stadium in Taiwan, completed in 2009 to host the World Games, has more than 8,800 solar panels on its roof. Charles Lin, director of Taiwan’s Bureau of Public Works, said, “The stadium's solar energy panels will make the venue self-sufficient in electricity needs.” When the stadium is not in use, it can power 80 percent of the surrounding neighborhood.Unlike solar cells, which use sunlight to generate electricity, concentrating solar power technology uses the sun’s heat. Lenses or mirrors focus sunlight into a small beam that can be used to operate a boiler. That produces steam to run turbines to generate electricity. This method will be used at the Solana Generating Station, which is being built by the APS utility company outside of Phoenix, Arizona, in the United States. When completed in 2012, Solana will be one of the largest solar power stations in the world. Once operating at full capacity, it will serve 70,000 homes.“This is a major milestone for Arizona in our efforts to increase the amount of renewable energy available in the United States,” said former Arizona Gov. Janet Napolitano.There are some challenges with solar power. First, it is intermittent, or not continuous. When there is no sun—at night, for example—power cannot be generated. In order to provide continuous power, either storage or other energy sources, such as wind power, must be used. Second, while both photovoltaic and concentrating solar power can be used virtually anywhere, the equipment they require takes up a lot of space. Installation, except for on existing structures, can have a negative impact on the ecosystem by displacing plants and wildlife. Lastly, the cost to collect, convert and store solar power is very high. However, as technological advancements are made and demand rises, the costs are dropping.Fossil fuels, such as coal, oil and natural gas, currently produce most of our electric and engine power. They also produce almost all of our pollution. Plus, they are non-renewable, meaning there is a limited supply.The sun, on the other hand, offers free and clean energy in abundance. In fact, it gives much more energy than we can ever possibly use. The only questions are how and when we will take full advantage of it.Source: Classwork #1 The Power of the SunName: __________________________6th Grade PSI ScienceOrganisms on Earth would not survive without the sun.Why do plants need sunlight?Why do animals need sunlight?How does the sun help to transport water?What is one positive aspect and one negative aspect for using solar powered technologies?Fill in the following table using information from the article.TechnologyDescriptionHow is it used?(Examples)Solar architectureGreenhouseSolar cookerSolar cellsSolar powerThe Birth of Our Sun & Solar System HomeworkName: _____________________6th Grade PSI ScienceTrue or False: Every object in our solar system revolves around our Sun.The sun comprises how much of the mass in our solar system?Our Sun is essentially a giant ball of fire. What is the fuel that keeps this fire burning?Explain how the sun formed.Explain how the planets formed.Classwork #2 PlanetsName: ___________________________6th Grade PSI ScienceThere are a variety of planet types in the universe. Until the 1990s, scientists only knew about the terrestrial planets and the gas giants in our own solar system. Over the past few decades, however, scientists have successfully identified over 230 planets outside our solar system!Many scientists are interested in investigating Earth-sized planets. To do so, they have created models that show how the composition of a planet would affect its approximate size. The illustration below shows how varying types of matter relates to diameter. All of the planets on the top row have the same amount of mass as Earth. They are composed of different types of mass. For example, a pure water planet composed of an equal amount of mass as Earth would be larger in diameter than Earth.Why do different compositions result in different sizes? The answer has to do with gravity. Remember that planets are held together by gravity. The inward pull of gravity is able to compress matter differently. A pure water planet is larger than a silicate planet because gravity is able to compress silicate more strongly than water. This compression pulls the silicate together, making it appear smaller.Source: NASA How does the size of a pure hydrogen planet relate to the size of a carbon planet?What type of composition is gravity able to compress the most?True or False: All of the “5 Earth masses” planets have varying strengths of gravity. Explain your answer.By following these models, scientists are able to predict the composition of planets. The graph below shows the relationship between mass and diameter of different types of planets. When a planet is discovered, scientists can measure its mass and diameter. They then apply the data to a similar type of graph to determine the planet’s composition.If a planet has a mass of 4 and a diameter of 2, what is its composition?Using this graph, what two types of planet compositions would be difficult to distinguish? Why?Classwork #3 Types of Celestial BodiesName: __________________________6th Grade PSI ScienceCelestial BodyDescriptionPlanetDefinition:3 Requirements:Terrestrial:Gas giants:Dwarf PlanetDefinition:2 Requirements:MoonDefinition:AsteroidDefinition:CometDefinition:Nucleus:Coma:Tail:MeteoroidDefinition:Meteor:Meteorite:Types of Celestial Bodies HomeworkName: __________________________6th Grade PSI ScienceWhat is a celestial body?What shape do all planets have?When the planets are listed in order, their first letters go M-V-E-M-J-S-U-N. One common pneumonic device is “My Very Educated Mother Just Sent Us Nachos.” (A pneumonic device is a memory tool using the first letter of each word!) Using the letter order above, write your own pneumonic device for the order of the planets.Why is Pluto no longer considered a “planet?”What is a synonym for “moon?”Why is an asteroid not considered a planet?Why is an asteroid not considered a moon?What causes a comet to look like it has a “tail” trailing behind it?Classwork #4 Motions of Objects Around the SunName: _______________6th Grade PSI ScienceAll of the planets in our solar system revolve around the sun. It takes the Earth 365 days to complete one revolution around its orbit. Other planets, however, complete revolutions in varying amounts of time. The table below lists the distance of each planet from the sun, rounded to the nearest million, as well as the time required to complete one revolution (orbit period). Use this information to create a graph illustrating the relationship between distance from the sun and revolution time.PlanetDistance from sun (km)Distance from sun (light-years)Orbit Period (Earth years)Mercury58,000,0000.2Venus108,000,0000.6Earth150,000,0001Mars228,000,0002Jupiter778,000,00012Saturn1,427,000,00029Uranus2,871,000,00084Neptune4,498,000,000165DirectionsComplete the graph by converting the distance from the sun from km to light-years. (Remember: light can travel 1012 km in one year.) Write your answer in scientific notation.Determine the values of the x-axis (distance). Write them in with appropriate spacing.Determine the values of the y-axis (orbit period). Write them in with appropriate spacing.Plot each planet’s data. Label each dot with the planet name.Connect the dots to create a line graph.?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Distance (light-years)Orbit PeriodWhat is the relationship between the distance of a planet from the sun and the time it takes to complete one revolution around its orbit?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Motions of Objects Around the Sun HomeworkName: _____________________6th Grade PSI ScienceOne revolution of the Earth takes 365 days and is equal to one _______________.Which planet has the shortest revolution around the Sun?The strength of the force of gravity depends on two things. Name them. What holds everything in our solar system in orbit around the Sun?The planets do not orbit the Sun in a perfect circle. What is the shape of their orbit?Classwork #5 Gravity of the Moon Name: __________________________6th Grade PSI Science In our slides, we learned that objects on the moon would weigh 1/6 of what they weigh on Earth.The example in the slides showed a dog that weighs 100 lbs on Earth would weigh about 17 lbs on the Moon. But how was this number decided?To convert from Earth weight to Moon weight, you can do one of 2 things:1)Multiply the Earth weight by 1/6100 lbs x 1/6 = 16.67 lbs2)Divide the Earth weight by 6100 lbs / 6 = 16.67 lbsBoth situations above give you the same results. Multiplying by the fraction 1/6 is the same as dividing by 6! Convert the Earth weights below to what the object would weigh on the Moon. You may use a calculator but you MUST show all work. Don’t forget to include the units. Use the information above to help you.Weight of a barbell on Earth = 45 lbsFind the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of a barbell on the Moon = _________________________________________________Weight of a German Shepherd on Earth = 82 lbsFind the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of a German Shepherd on the Moon = _________________________________________Weight of a student on Earth = 100 lbsFind the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of a student on the Moon = _________________________________________________Weight of a Mercedes on Earth = 6,000 lbsFind the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of a Mercedes on the Moon = _______________________________________________Weight of an elephant on Earth = 15,000 lbsFind the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of an elephant on the Moon = _______________________________________________Weight of YOU on Earth = ________________________________________________________Find the weight on the Moon using multiplication: ____________________________________Find the weight on the Moon using division: _________________________________________Weight of YOU on the Moon = _____________________________________________________Classwork #6 Moon PhasesName: __________________________6th Grade PSI ScienceThe percentage of the moon that is visible to us on Earth changes in a cyclical manner. The graph below illustrates this information. Use the graph and your knowledge from class to answer the following questions.According to the graph, how long is one cycle of the moon?Locate the position of the new moon on the graph. Place a dot on it and label it “new moon”.Locate the position of the full moon on the graph. Place a dot on it and label it “full moon”.Locate two areas where the moon is waxing. Label these sections of the graph “waxing”.Locate two areas where the moon is waning. Label these sections of the graph “waning”.The moon is always half lit by the sun. Explain why it appears to change shape to us on Earth.For each of the following phases, describe the location of the moon, the percentage of the moon that is visible and explain why that much is visible.Moon PhaseLocation% VisibleExplanationFull MoonNew MoonEarth’s Moon HomeworkName: __________________________6th Grade PSI ScienceOf what is the moon believed to be made?About how old do scientists believe the moon is? How do they think it formed?Define the following terms: exospherevacuumHow is a crater formed?What causes the moon to shine in the night sky?How long is a sidereal month? How long is a lunar month?What is the difference between a sidereal month and a lunar month?Why are we always able to see the same side of the moon?Classwork #7 TidesName: __________________________6th Grade PSI ScienceWhy does the moon affect Earth’s surface water?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________The Moon’s gravity pulls on the Earth’s surface water to create a high tide. What is the cause of the high tide on the opposite side of the planet at this time?EarthMoon________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________What is the result of a spring tide?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________The image below shows the Earth and the sun. Draw in the two positions that the moon can take during a spring tide. Label each moon with the phase that it represents.What is the result of a neap tide?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________The image below shows the Earth and the sun. Draw in the two positions that the moon can take during a neap tide. Label each moon with the phase that it represents.Tides HomeworkName: __________________________6th Grade PSI ScienceThe term “perpendicular” refers to what type of angle?Define the term tides.Why does a spring tide result in large high tides and small low tides?Why does a neap tide result in small tidal fluctuation?The Moon’s gravity affects all water on Earth. Why can’t we see any noticeable change in puddles or small ponds?Solar Eclipses"The Sun Is Blotted From the Heavens"Solar eclipses have been recorded as important events by humans for millennia. References have been found in some of our earliest texts, including ancient Chinese academic documents and even a line from Homer's Odyssey that declares, "The sun is blotted from the heavens."It's easy to imagine how our earliest ancestors must have reacted to the sudden disappearance of the sun, and over time the phenomenon has been seen as both fascinating and terrifying, a signal of the displeasure of the gods, or an omen of bad things to come.These rare, mesmerizing sky shows result when the moon aligns between the Earth and the sun, blocking the sun's light and casting a shadow on our planet. As Earth spins, this shadow races at some 1,400 miles an hour (2,250 kilometers an hour) along a line called the path of totality.Only sky watchers within this arc—typically 10,000 miles (16,000 kilometers) long and just 100 miles (160 kilometers) wide—experience a total eclipse. People near it see a partial solar eclipse in which not all of the sun is blotted out. Those farther away see nothing at all.A total eclipse begins as a barely perceptible nibble out of the sun. Over the next hour or so this blemish widens and eventually consumes the sun, turning day to night. This state, called totality, can last as long as seven and a half minutes, although it is usually half that.During totality, the only visible part of the sun is its corona, the normally unseen outer atmosphere that shimmers in the darkness like a fiery ring. When the sun begins to reappear, there is often a sparkling glow in one spot along the corona that creates what's known as the diamond ring effect. Within about an hour, daylight is restored.Only During the New MoonEclipses happen only during the new moon phase, when the moon moves to the side of Earth facing the sun. However, because the moon orbits Earth at a slight angle, the three bodies will only periodically line up on the same plane to create an eclipse.Interestingly, total eclipses are only possible on Earth because of a fortuitous coincidence: The moon's diameter and distance from Earth make its relative size just big enough to cover the sun. If the moon were any smaller or farther away, we would only see partial eclipses. In fact, in a billion years or so, the moon will have drifted so far from Earth that solar eclipses will no longer occur.Another type of solar eclipse, the annular eclipse, occurs when the moon's elliptical orbit carries it far enough from Earth that it becomes too small to totally block the sun. In this case, the eclipse appears as a blackened circle rimmed by sunlight.Total eclipse occurs every one or two years, while total and partial eclipses together average about two and a half incidences per year. But because they are visible from such a small area on Earth each time, the chance of observing a total eclipse from any single spot is less than once in a lifetime.Seeing a solar eclipse can be an unforgettable experience, but experts urge caution. Looking directly at the sun through a telescope or binoculars (or even the naked eye) can cause eye damage and even permanent blindness.Classwork #8 Solar EclipsesName: _____________________6th Grade PSI ScienceWhat causes a solar eclipse?A solar eclipse casts a shadow on the Earth. What is the speed of this shadow as the Earth rotates?Describe the area of a total eclipse.What is the path of totality?Total eclipses occur during what moon phase?What two characteristics of the moon make total eclipses possible? How is an annular eclipse different from a total eclipse?Eclipses HomeworkName: __________________________6th Grade PSI ScienceHow would a solar eclipse look if you were in the umbra compared to the penumbra? What is the difference between a lunar and a solar eclipse?Define the term eclipse. What phase must the moon be at in order to be a part of a lunar eclipse? What time of day must it be in order to see a lunar eclipse? (Night or day?)Classwork #9 SeasonsName: _____________________????????1??????????????????????????????????????????2????????????????????????????????????????3???????????????????????4???5???????????????7?????????6??????????????????????????????????????????????????8??????????????????????????????10?????????????????????????????????????????????????????????9???????????????????????????????????????????????????????????6th Grade PSI ScienceDown1 – Half of the Earth5 – The spring month in which day and night are equal6 – Occurs when day and night are equal7 – The autumn month in which day and night are equal10 – The month in which the sun is tilted closest to the sun (in the Northern Hemisphere)Across2 – The line that divides the Northern and Southern hemispheres3 – The seasons occur because Earth is tilted on its _____.4 – The line that divides the Eastern and Western hemispheres.8 – Marks the beginning of summer and winter.9 – The month in which the shortest day occursSeasons HomeworkName: __________________________6th Grade PSI ScienceThe North Pole is always pointed toward the Sun. True or False? If false, then explain the correct response. If you are a fan of warm weather and hate the cold, where on Earth would be the best place to move? Why? On what two days of the year will daytime and nighttime be equal?Rewrite the sentence, filling in the blanks with the correct terms: The Earth ________________________ on its axis and ___________________________ around the Sun. The Sun is higher in the sky during which season? What effects do longer days have on the Earth’s surface? What is the difference between the Winter and Summer Solstices? (It’s MORE than just the date!)The Birth of Our Sun and Solar SystemClasswork #1 Answer KeyOrganisms on Earth would not survive without the sun.Plants need the sun to make food and grow.Animals need the sun for heat. They also need plants, who rely on the sun, for food and oxygen.The sun transports water via the wind, ocean currents and clouds.Answers may vary. Positive: it is a renewable resource and would decrease pollution. Negative: when there is no sun, there is no energy.TechnologyDescriptionHow is it used?(Examples)Solar architectureUsing building techniques that make use of the sun via shadows, heating and ventilation.Direction of a building; location of windows and skylights; choosing appropriate building materials.GreenhouseConverts sunlight to heat so that crops can be grown year round.Thin sheets of glass convert sunlight into heat where crops are located.Solar cookerA box that uses sunlight to generate heat.Used for cooking, drying, pasteurization and sterilizationSolar cellsConvert sunlight into electricity. Many must be used to generate an adequate amount of electricity.Used in calculators, watches, homes and stadiums.Solar powerFocuses sunlight to generate heat that operates a boiler. The boiler’s energy is used to generate electricity.Power generating stationsHomework Answer KeyTrue99%The Sun is fueled by gas.Our Sun likely began as a nebula which could have formed from a supernova. This nebula collapsed under its own weight and formed a spinning cloud of gas that began heating up.Our planets probably formed from small bits of ice and rock that orbited the Sun. Over time, these pieces collided and bunched together, growing larger over millions of years.Types of Celestial BodiesClasswork #2 Answer KeyA pure hydrogen planet is much larger than a carbon planet.Pure ironFalse. All of the “5 Earth masses” planets have the same strength of gravity. They are different sizes due to gravity’s ability to compress matter.a. Pure water planetb. Carbon planets and silicate planets would be difficult to distinguish. Their values are so similar that natural variation in planet sizes would make it very difficult to determine which line a new planet falls on.Homework Answer KeyA celestial body is any natural body outside of Earth’s atmosphere. All planets have a spherical shape.Natural satelliteAnswers can varyPluto is no longer considered a planet because it is not the most dominant body in its orbit.Asteroids are too small to be considered planets.Asteroids are not considered moons because they do not orbit a planet, they orbit the Sun.The tail becomes visible when the comet comes near the sun and begins to melt. It becomes visible as the sunlight reflects off of the dust and causes the gas to glow.The Motion of Objects Around the SunClasswork #4 Answer KeyPlanetDistance from sun (km)Distance from sun (light-years)Orbit Period (Earth years)Mercury58,000,0006 x 10-50.2Venus108,000,0001 x 10-40.6Earth150,000,0001.5 x 10-41Mars228,000,0002 x 10-42Jupiter778,000,0008 x 10-412Saturn1,427,000,0001 x 10-329Uranus2,871,000,0003 x 10-384Neptune4,498,000,0004 x 10-3165As distance increases, the orbit period increases.Homework Answer KeyYearMercuryGravity depends on the size of the two objects and the distance between them.GravityEllipses (oval-shaped)Earth’s MoonClasswork #5 Answer Key7.5 lbs13.7 lbs16.7 lbs1,000 lbs2,500 lbsAnswers will vary.Classwork #6 Answer Key30 daysFull moonNew moonWaxingWaxingWaningWaningAs the moon revolves around the Earth, the amount of the moon’s sunlit side that is visible on Earth changes.Moon PhaseLocation% VisibleExplanationFull MoonOn the far side of the Earth, away from the sun.100At the farthest point in its revolution, the entire lit portion of the moon is visible to Earth.New MoonBetween the sun and the Earth.0Since it is between the Earth and the sun, the entire lit portion of the moon is hidden from Earth. We cannot see the moon at all.Homework Answer KeySome people say the moon is made of cheese, but, like Earth, it is actually made of minerals, rocks and metals. Scientists estimate the Moon is about 4.5 billion years old. The moon formed as debris from a collision between Earth and another celestial body.Exosphere – A very thin layer of gases on the MoonVacuum – A space that is entirely empty of matterA crater forms when the surface of a celestial body (such as the Moon) is impacted by another object.The moon shines because it is reflecting sunlight back to the Earth.A sidereal month is 27.3 days. A lunar month is about 29.5 days.A sidereal month is the period of time it takes for the Moon to complete one full revolution of the Earth. A lunar month is the time between Full Moons (or New Moons). A lunar month is affected by the motion of the Earth.It takes the moon the same amount of time to rotate about its axis and revolve around the Earth.TidesClasswork #7 Answer KeyAll celestial bodies have gravity. The moon’s gravitational pull on Earth and Earth’s water causes the tides.As the moon pulls the water, the water on the side of the Earth closest to the moon moves towards it, causing a high tide. The moon’s gravity also pulls on the Earth. As the Earth moves slightly towards the moon, the water on the other side of the Earth remains in place, causing it to also be a high tide.Spring tides cause larger high tides and smaller low tides.New moonFull moonNeap tides cause smaller high tides and low tides.First Quarter MoonThird Quarter MoonHomework Answer Key90° angleTides are the rise and fall of Earth’s surface water due to the force of gravity between the Earth and the Moon.During a spring tide, the sun, moon and Earth are in a straight line. This makes the sun’s gravity and the moon’s gravity pull on Earth, creating higher high tides and smaller low tides.During a neap tide, the moon is pulling on Earth perpendicularly to how the sun is pulling on the Earth. The two forces counteract each other and Earth experiences very small tidal fluctuation.We can’t see any changes because the amount of water is so small.EclipsesClasswork #8 Answer KeyA solar eclipse occurs when the moon is positioned between the sun and the Earth, causing a shadow to fall across the Earth.1,400 mph (2,250 km per hour)10,000 miles (16,000 km) long and 100 miles (160 km) wideThe path of totality is the pathway of the shadow across the Earth and it rotates on its axis during an eclipse.New moonThe size of the moon and the distance from Earth make a total eclipse possible. An annular eclipse occurs when the moon’s orbit takes it farther from the Earth during an eclipse. This makes the moon appear smaller and it only blocks out the middle portion of the sun.Homework Answer KeyIf you were standing in the umbra, you would see a total solar eclipse. If you were standing in the penumbra, you would see a partial sola eclipse.During a lunar eclipse, the Earth’s shadow is blocking out the moon. During a solar eclipse, the moon’s shadow is being cast on the Earth, blocking out the Sun.An eclipse is the hiding of one object in space by another, or the passing of an object in space into a shadow cast by another object.Full moonNightSeasonsClasswork #9 Answer KeyDown1 – hemisphere5 – March6 – equinox7 – September10 – JuneAcross2 – equator3 – axis4 – prime meridian8 – solstice9 – December Homework Answer KeyFalse; The Earth is always tilted in the same direction. For half of the year, the North Pole is positioned in such a way that it is always day time. For the other half of the year, it is pointed away and it is night.You would like it best on the Equator because the temperature will stay consistently warm for the entire year. This is because points at the Equator will remain the same distance from the Sun year-round.Spring Equinox and Autumnal EquinoxThe Earth rotates on its axis and revolves around the Sun.The Sun is highest in the sky during the summer. The Sun will be more directly overhead.Longer days mean that the Sun will have more time to heat the surface of the Earth. That will make the air and water temperature warmer.Winter Solstice is the shortest day of the year and the Summer Solstice is the longest day. ................
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