Our Big Blue Marble

Earth's Seasons

Our planet rotates on its imaginary axis at a surface speed of about one-half kilometer per second at the equator and revolves around the Sun at about 30 km per second. That's fast, but because motion is relative, we do not feel it. To us, the Earth seems to be standing still. Instead, we experience the motion of the Earth in the movement of the Sun across the sky and in the much slower cycle of the seasons. The four seasons are a result of Earth's axis of rotation being tilted at 23.5o.

Earth's Atmosphere

A thin layer of atmosphere — composed of 78% nitrogen, 21% oxygen, and 1% other constituents — separates us from the vacuum of space, shields us from harmful radiation coming from the Sun, and protects us from meteors, most of which burn up before they can strike the surface of the Earth. The part of the atmosphere that we call home — the troposphere — is an even thinner shell, only 12 km (7.5 mi) thick. It is in the troposphere where all our weather occurs.

Earth's Hydrosphere

Figure 2. The Earth's water cycle.

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Water is liquid only within a narrow temperature span (0 to 100 oC). Contrasted with the full range of temperatures found in the solar system, this temperature span is especially narrow, neither too hot nor too cool. Fortunately for us, 70% of Earth's surface is covered by water: lakes, ponds, rivers, streams, creeks, oceans, seas, estuaries and tide pools. The rest of Earth is land: mountains and valleys, volcanoes, plains, deserts, forests and the boundary zones known as wetlands. Water vapor in the atmosphere is responsible for much of the Earth's weather and produces the water cycle that transports water as rain to sustain plant life on land. The water cycle (see Figure 2) consists of water evaporating from bodies of water and plants. It then condenses to form clouds, which travel around the planet. The clouds release the water as precipitation and then it flows back into bodies of water.

Earth's Lithosphere

The Earth is not a solid mass; it has several distinct layers, of which some are rigid and others are "plastic" or movable. The Earth's brittle crust floats on a liquid layer called the asthenosphere (see Figure 3). This liquid is molten rock (rock that has melted because of intense heat). We see this molten rock when it escapes as lava from volcanoes. The land masses of Earth are plates, rather like slices of bread floating on a very thick soup. These plates run into each other, under each other, and push against each other, causing earthquakes.

Figure 3. The layers of the planet Earth.

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Earth's crust is divided into 10 major plates that are constantly on the move. The North American plate, for example, is moving west over the Pacific Ocean basin. The rate of speed is imperceptibly slow, roughly the rate our fingernails grow. But in time, give or take a few million years, we could be shaking hands with China. When the plates grind past one another causing earthquakes, we become suddenly aware of the movement of the plates. The plates also ride up over one another, or collide to make mountains, or split and separate. These movements are known as plate tectonics, a study that has fully developed only within the last 40 years.

Earth's Magnetosphere

Our planet's molten iron-nickel core and rapid spinning on its axis cause it to behave like the small bar magnets we have on Earth. The Earth has a North and a South Pole. However, satellite mapping has revealed that due to the effects of the solar wind (streams of charged particles emitted from the Sun) the magnetosphere is shaped more like a teardrop and has definite boundaries (see Figure 4).

Figure 4. The Earth's magnetosphere surrounds the planet and protects it from harmful cosmic rays and solar "winds."

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Planet Quick Facts

Amazing facts about Earth may be found in Table 1.

Table 1. Facts about Earth.

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From: https://www.teachengineering.org/view_lesson.php?url=collection/cub_/lessons/cub_solar/cub_solar_lesson04.xml

Mercury & Venus

We are going to learn about all eight planets, but today we are just going to focus on the first two – Mercury and Venus. Did you know that Mercury is the second smallest planet in our solar system? It travels faster around the Sun than any other planet; it takes only 88 days to rotate around the Sun. Mercury looks a lot like Earth's Moon. It has cliffs and valleys and craters. What do you think the Sun looks like from Mercury? Well, it looks two to three times larger than how we see it from Earth. Depending where you are on Mercury, you would see the Sun move in a strange pattern during the day. The Sun would rise, then seem to set (appearing to grow smaller), and then start to rise again. The same thing happens in reverse when the Sun sets. This is due to Mercury's egg-shaped orbit and the number of times it rotates in a given year.

Venus is the second planet from the Sun. It is also the second brightest object in our night sky, besides our Moon. If you were to sit on the surface of Venus, it would look like a cloudy, drizzly day. Scientists think that Venus once had water, but that it has long since evaporated; now it rains sulfuric acid. The temperature on Venus is in excess of 900 oF (480oC) during the day, because the clouds trap in heat from the Sun instead of releasing it to the atmosphere. In fact, it is hotter on the surface of Venus than Mercury, because Mercury does not have the thick clouds. Venus's atmosphere is thick and poisonous, with strong winds and lightening. The atmospheric pressure on the surface would crush metal spacecraft in a few hours. Venus is not a friendly place for humans to visit. One more interesting thing about Venus is that it spins in the opposite direction than the Earth spins, so for us it would look like the Sun moves backwards across the sky.

We know that Mercury and Venus are the first and second planets nearest the Sun, and we know that they have some characteristics that are pretty different from Earth, but who can tell me how we find out about the planets? Since Venus is so hot on its surface, it is way too dangerous to send people there. So, how do we know what it is like? That's right; we have to design something to remotely investigate the planet for us. From Earth, we can observe the planets through telescopes. However, to get more details and measurements of temperature and atmosphere and surface conditions, we must send a spacecraft to the planet. Who do you think gets to design systems to tell us about the planets? That's right – engineers do! Engineers design special space equipment and spacecraft to help us learn more about outer space and the planets.

Mercury

Mercury is the closest planet to the Sun and the second smallest of our planets. Mercury was named for the Roman messenger of the gods, because it seemed to move faster than any of the other planets in the sky. In fact, Mercury travels around the Sun every 88 days.

Engineers and scientists built the Mariner 10 spacecraft and it passed within 12,000 miles from the surface of Mercury in 1974. Mariner 10 relayed detailed information about Mercury's surface conditions, such as temperature, to the Earth. Mariner 10 was only able to view part of the planet. A spacecraft named Messenger was launched in 2004 to fly by Mercury three times, with the mission to map the entire planet and study its shape, interior and magnetic field.

Before sending it to space, a thermal engineer checks the condition of the Messenger spacecraft's ceramic-fabric sunshade after testing it in a vacuum heat chamber to make sure it will keep its instruments and systems at room temperature while the spacecraft orbits Mercury, the planet closest to the Sun.

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Mercury's surface has been hit many times by meteorites; thus, it resembles our Moon. Mercury does not have plate tectonics, but has lava flows. According to NASA, ice caps appear to exist on the North and South Poles, and deep inside of craters. Scientists believe that the ice can exist because the areas where it always remain in shadow. Mercury is thought to have a dense iron core and a thin mantle and crust. The core's radius is approximately 1,800-1,900 km, while its crust and mantle are only about 500-600 km thick.

Mercury's surface is a lot like the Earth's Moon: it has a barely detectible atmosphere, no known life, and craters of all sizes. Unlike the Moon, the temperature ranges from 800 oF (430 oC) in the day to 280 oF (140 oC) at night. If you were to stand on Mercury, the Sun would appear two to three times larger than it looks to us when standing on Earth.

Venus

Venus is the second planet from the Sun and its size is similar to the Earth. Venus was named after the Roman goddess of love. While Venus is almost the same size of Earth, it rotates retrograde. So, on Venus, the Sun rises in the west and sets in the east. During its orbit of the Sun, it comes within 26 million miles (42 million km) of the Earth.

To further explore the conditions on Venus, over the years engineers have designed a few probes to enter its atmosphere. But they do not last long, as surface conditions are extremely hostile! A thick atmosphere of carbon dioxide encloses Venus, and the atmospheric pressure is 90 times that of the Earth's. It rains sulfuric acid. Daytime temperatures reach up to 900 oF (480 oC) year round. Probes that have landed on Venus have not survived more than a few hours before being destroyed by the incredibly high temperatures. It is a greenhouse gone wild! These thick atmospheric clouds also reflect sunlight, making Venus often the brightest planet in our sky.

Aine Corona with Pancake Domes, 1991: To see past the thick atmospheric clouds on Venus, engineers designed the Magellan spacecraft to use radar to collect data as it flew by the planet. They used the data to create images to map the planet, such as this 300-km (180-mi) wide area that reveals to us the planet's surface texture of circular corona fractures and flat-topped lava domes.

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Venus's gray rocks appear tinted yellow from the Sun shining through the atmosphere. The many volcanoes on Venus vary in size from large mountains to small domes. Volcanic eruptions shape the surface of Venus. With very little surface wind and no water (so unlike the Earth), these factors play little part in erosion. But, the winds at high elevations are stronger, and are known as super-rotation; they circulate Venus every four days. Like Earth, Venus has atmospheric circulation patterns between the equatorial and polar areas. Venus shows no evidence of plate tectonics, which on Earth are an important way for planetary heat release. Instead, large, circular patterns called coronae form on the surface, causing surface warps as they release hot material from below the surface.

The Sun

What is 25 million degrees Fahrenheit at its center (14 million degrees Celsius) and made of gas? You guessed it, the Sun! The Sun is a huge, hot ball of gas that is the center of our solar system. The Sun is so large that a million Earths could fit inside of it. While the sun has a relatively low average density, about 1.4 times the density of water, its large size causes it to have an incredible amount of mass. The large mass of the Sun means that it has a very powerful gravitational pull. (Note: The average density of the Sun is 1.4 times the density of water; the average density of the Earth is 5.5 times the density of water.)

The Sun is 93 million miles (150 million km) from our planet, but it still supplies us with almost all of the energy that we consume. The Sun's energy reaches the Earth in the form of heat, light and radiation. Without this energy, life could not exist on or planet. For example, all the fruits, vegetables and grains we eat use photosynthesis to turn energy from the Sun into energy for us. When we eat these plants we get the energy we need to walk, run, talk, throw, etc. We also eat animals that eat plants. The energy gets transferred from the plants to the animals and then to humans. Take a hamburger, for example. The lettuce, tomato, onion, bun, ketchup and mustard all come from plants. The egg in the mayonnaise comes from a chicken that gets its energy from eating plants. The hamburger comes from a cow that gets its energy from eating plants. As we can see, everything we eat gets its energy from the Sun. Without the Sun we would not be able to get the food we need to live.

So, what about other sources of energy? From where does the electricity we use in our houses and schools come? What about the energy to power our computers, lights, cars, trains, boats and planes? Most of the energy we use in our homes comes from burning fossil fuels such as coal and oil. Our transportation devices, such as automobiles, trains, boats and planes, almost all use fossil fuels (usually oil). Fossil fuels are made from decayed plants and animals from millions of years ago. From where do you think all those plants and animals got their energy? That's right — their energy came from the Sun. Other types of energy, such as solar, wind and hydroelectric, all require the Sun to provide power. Without the Sun, the Earth would be a frozen and dark ball with no life.

Figure 2. The layers of the Sun, from the center out: core, radiative zone, convection zone, photosphere, chromosphere and corona.

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The Sun is not on fire like we think of fires on Earth. Oxygen is not required; the Sun is a big nuclear fusion reaction. If the Sun did behave like a fire on Earth, it would have burnt out long ago. So what keeps the Sun alive? The Sun is mostly made of hydrogen gas. This hydrogen is fused with other hydrogen to form helium. This process creates an immense amount of energy that we see as light and feel as heat. How long do you think it takes energy from the Sun to reach our planet? Because the Sun is so far away, it takes the energy from the Sun eight minutes to reach us on Earth.

Figure 3. Engineers designed the Arecibo radio telescope in Puerto Rico - the largest single-dish telescope on the planet.

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The Sun does not have a solid surface where we could stand, like on our planet. It has many different layers (see Figure 2). At the center is the core where the fusion of hydrogen takes place. Then, the energy passes through the radiative (or radiation) zone and the convection zone. The outermost layers of the Sun include the photosphere, chromosphere, and the corona. The visible surface of the Sun is the photosphere; it is from here that the light from the Sun comes. The next layer is the chromosphere, which is a thin layer of transparent hot gas around the photosphere. The outermost layer of the Sun is known as the corona. Humans can only view the corona with the naked eye during a solar eclipse (even then, one should never look directly at the Sun, as it can cause permanent eye damage).

So, how have we learned so much about the Sun? Since people should not look directly at the Sun, we must create special devices that can look at the Sun for us and gather information for us. These devices include telescopes, cameras, sensors and satellites. These scientific instruments are designed and built by engineers. Huge ground-based telescopes are built by civil, mechanical and electrical engineers (see Figure 3). Aerospace, mechanical and electrical engineers design the satellites that look at the Sun and gather data from nearer the Sun. Without this scientific equipment we would not know everything we know about the Sun.

From: https://www.teachengineering.org/view_lesson.php?url=collection/cub_/lessons/cub_solar/cub_solar_lesson02.xml

Destination Outer Space

Basic Rocket Science and Rocket Components

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Rockets are essentially a massive sustained explosion in which the hot gases from the combustion process are directed to create thrust. Of course, it is a very carefully controlled and directed explosion — no small engineering feat! Engineers must design fuel tanks and nozzles that are just the right size, shape and thickness to withstand the pressure of the explosion and accelerate the fuel away. Engineers also design materials and components that can handle the heat and vibrations generated. If their design is too heavy, the rocket may be strong but will not fly; if it is too light, the rocket structure may be too weak and explode.

Rockets move according to the natural behavior described in Newton's third law of motion: for every action there is an equal and opposite reaction. This means that a rocket moves forward by pushing hot gas backwards. The hot gas moving backward is the action, while the rocket moving forward is the equal and opposite reaction. How much power the rocket provides is called "thrust." To create thrust, volatile fuel is placed in a combustion chamber and ignited. When the fuel is ignited, it creates super-heated gas that expands, creating incredible pressure in the combustion chamber. A small opening in the combustion chamber lets the high pressure gasses escape, and a nozzle directs the gas into the desired direction. This is why we see fire and smoke coming from a rocket as it lifts off.

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Other common rocket elements include fins, fuel tanks and nose cones. The fins are small wings that keep a rocket moving straight ahead. The great amount of energy required to leave the Earth's surface comes from fuel stored in huge fuel tanks. The nose cone on the tip of the rocket helps the rocket slice through the air. Without the nose cone, it would be much harder for the rocket to move though the atmosphere on the way to space.

Main components of the space shuttle.

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On a typical spacecraft, we might also see heat shields, antennae, parachutes, computers, scientific instruments, solar panels and thrusters. The heat shield protects the spacecraft from the heat of re-entry, while parachutes are often employed to ensure a safe landing. Antennae are important for communicating with the ground and sending scientific data. Computers monitor the spacecraft and help the astronauts operate the craft and perform experiments. Thrusters are small rockets that maneuver the spacecraft while it is in space. Solar panels help provide the craft with power; they turn the Sun's rays into electrical power.

The US space shuttle is designed to transport people and cargo to and from orbit around Earth. The main space shuttle components are two solid rocket boosters (contains solid fuel used to push the shuttle into the air), an external tank (holds liquid fuel) and the orbiter (includes a crew cabin for up to seven people; a cargo bay for supplies and equipment, and three engines). A great amount of the space shuttle is devoted to providing fuel. After liftoff, when the solid rocket fuel is gone, the boosters fall back down to Earth. Next, when empty, the external tank comes off. Then, the orbiter reaches space; it is able to return to Earth and land like an airplane. Everything except the external fuel tank is used for another shuttle flight.

Engineers are responsible for all these rocket, spacecraft and shuttle elements. Without them, space travel would not be possible. It is when all these carefully-designed elements work together that we have a successful space mission.

Vocabulary/Definitions

chemical reaction:	A process in which one type of substance is chemically converted to another substance involving an exchange of energy.
engineer:	A person who applies his/her understanding of science and math to creating things for the benefit of humanity and our world.
gas:	Tiny particles with enough energy to remain isolated and free floating (as opposed to liquids and solids in which particles group together).
Newton's third law of motion:	For every action there is an equal and opposite reaction. (This is why rockets work!)
pressure:	The exertion of force upon a surface by an object, fluid, gas (etc.), in contact with it. Force per area. Measured in units of pounds per square inch (psi) or newtons per square meter (N/m^2) or pascals (Pa). Pressure results from collisions of gas molecules with a surface
rocket:	A vehicle that moves by ejecting fuel.
thrust:	The forward-directed force on a rocket in reaction to the ejection of fuel. From: https://www.teachengineering.org/view_lesson.php?url=collection/cub_/lessons/cub_solar/cub_solar_lesson01.xml

Study Guide for Science Test

Tomorrow we have a science test. Here is an AWESOME website that will help you review the concepts that are on the test.

Review website click: HERE

You can also get on the other rock websites and it will help you review.

In addition to websites here are a few concepts you will need to know for the test.

·         Vocabulary: streak, hardness, igneous rock, deposition, sedimentary rock, metamorphic rock, erosion, rock cycle

·         What is luster?

·         How does sedimentary rock become sedimentary? How do they become metamorphic? How do they become igneous?

·         What is found in soil?

·         What are minerals?

·         Classification of rocks (how to test hardness and streak)

·         What is weathering? What is erosion?

Happy studying you rock hounds. You will "ROCK" this test....hahahaha...man I crack myself up!

Rosa Parks

Did you know today, February 4, 2016, is Rosa Parks' birthday?! How perfect as the 5th grade has been studying the impact of Rosa Parks and the leader she was. Ask your students about the impact that she has made, even on us today.

Here is a video I found to learn more about Rosa Parks. Let me know if you find any neat websites about her that you would like to share for your friends.

click here for video: VIDEO

Science Website

Hello fellow scientists!!

We are studying layers of the earth, rock cycle and earth processes. Check out this link below to investigate further about the things we are learning in class. Please see if you can find any other science websites and I would be more than happy to share them here.

http://interactivesites.weebly.com/earths-structure.html

http://interactivesites.weebly.com/earths-structure.html

Layers of the Earth Games!

http://www.wartgames.com

https://app.discoveryeducation.com/learn/videos/5C04739F-F083-44B6-8351-20BD8A98211A?hasLocalHost=false/themes/science/layers.html

Here are some websites about the rock cycle!

https://www.learner.org/interactives/rockcycle/index.html

http://www.oum.ox.ac.uk/thezone/rocks/games/level1.htm

http://www.wartgames.com/themes/science/rockcycle.html