Most Scientists Believe:
•The universe is finite and expanding. •All matter, energy, and space was once squeezed into a very small volume. •This resulted in a sudden expansion known as the Big Bang. •The name is misleading because it was not an explosion as we think of an explosion. •Occurred 13.7 billion years ago •Galaxies expand throughout the universe like raisins baked in a cake. •They become more distant from each other as the cake rises. •It’s the cake (space) that is expanding causing the raisins (galaxies) to move. Important Theories •Albert Einstein’s General Theory of Relativity and Sir Isaac Newton’s original Theory of Gravity concluded the universe was static (lacking movement). •This was later proved untrue and Einstein would call it his “biggest blunder.” Edwin Hubble •1929 – Discovered an electromagnetic property called the Red Shift •Explained why galaxies appear to be accelerating away from the each other •Contrary to Einstein the Universe was expanding Red Shift •Think of the Doppler Effect when a fire truck passes. •The sound waves are compressed in front of the train and make a high frequency sound. •After the fire truck passes, the wavelengths spread out making a low frequency sound. •Light emitted from a star or galaxy can be separated into a band of colors, called a spectrum. •Each color has a different wavelength just like sound has wavelengths. •Notice the longer wavelengths are toward the red end of the spectrum. •Light behaves like sound. •Just like sound, light has “pitch”. •The red end of the spectrum has a lower pitch, or frequency, than the blue end. •Think of it in sound terms, red colors are the low notes and blue colors are the high notes. •If a star is moving away from us, the light gets stretched out. •This makes it appear more red than it really is. •If a star is moving toward us, the light gets squeezed. •This makes it appear more blue than it really is. •This shift in the absorption lines of galaxies lead Hubble to conclude that the galaxies are moving apart from each other. •Space is actually expanding causing the galaxies to move with it. •First piece of evidence supporting the BBT Cosmic Microwave Background Radiation (CMB) •Scientists thought if there was a BB, then there must be remnants of energy left out there in the far reaches of the universe. •This energy was found in the form of microwaves and is coming at us from every point in the universe. •It was called “relic” radiation. •In the mid 1960’s, and totally by accident, two young scientists picked up mysterious microwave static coming from every direction in the sky. •This radiation was very cold, which was expected. •They concluded it must be the “afterglow” of the BB. •This is the second piece of evidence supporting the BBT. Hydrogen and Helium •Using powerful telescopes, scientists have concluded the universe consists of mainly hydrogen (74%) and helium (25%). •These are the lightest elements. Heavier elements make up the other 1%. •This continuity throughout the universe supports the BBT. •Third piece of supporting evidence for the BBT Fred Hoyle •English astronomer, Fred Hoyle, coined the phrase Big Bang in 1949. •Most scientists consider it to be the most likely scenario for the birth of the universe. •There is much more supporting evidence, which is not included in this lesson.
What is the EMS?
The complete range of frequencies of electromagnetic waves from the lowest to the highest Includes radio, microwave, infrared, visible light, ultraviolet, X-ray, and gamma ray waves Can be used to gather information about distant objects (stars, galaxies, etc.) Waves A disturbance that travels through space and matter Transfers energy, not matter Travel through electrical and magnetic fields Examples: light, microwaves, radio waves, and X-rays. Crest The highest point on a wave is called the crest. Trough The lowest point on a wave is called the trough. Wavelength The distance between successive crests or troughs Measures one complete wave Amplitude The maximum extent of a wave measured from the position of equilibrium Frequency The number of crests of a wave that move past a given point in a given unit of time Measured in Hertz (Hz) Radio Waves Longest wavelength Lowest frequency Coolest temperature Examples: FM/AM radio stations, stars Microwaves Need close proximity to transmitter Examples: microwaves, routers, cell phones, stars Infrared Waves “Infra” means below These waves are just below visible light Examples: remote controls, flames, lamps, stars Visible Light All visible light ROYGBIV Examples: light bulbs, fire, stars Ultraviolet Light Often called “black light” Examples: sterilization, stars (sunburn anyone?), haunted houses X-Ray High frequency waves Examples: see inside organisms, airport security, dentist office, stars Gamma Rays Highest frequency waves Highest temperature (blue) Examples: radiation therapy (cancer), sterilization, stars Studying the Universe Astronomers use all kinds electromagnetic waves to study the characteristics (temperature, energy, color) of stars. They can also use the EMS to determine chemical composition. Spectroscopy A measurement technique which allows astronomers to see light that is absorbed, emitted, or scattered by materials Star Composition Use the class set of absorption spectrums to determine which elements are present in each star. Parallax Astronomers can measure the distance of stars using a method called parallax. They measure the star twice per year. Every 6 months the Earth has moved nearly 186 million miles from it’s previous point due to its revolution around the Sun.
Science 7: HUMAN IMPACT ON WATER
ESSENTIAL QUESTIONS: 1.What is the difference between fresh and salt water? 2.What are examples of surface and groundwater? 3.What are the parts of an aquifer? 4.What are some different types of water pollution? 5. How can water be conserved? Water Cycle Review •Also called the hydrologic cycle •The journey water takes as it circulates from the land to the air and back again. •Involves evaporation, condensation, and precipitation. •Repeats as a never-ending cycle Natural Resource •Naturally occurring substances such a mineral, forest, water, and land that are used by humans. Renewable Resource •A resource that can be used repeatedly because it is replaced naturally (cycle). •Water fits both these criteria. Watershed •Basin-like land formation defined by highpoints and divides that descends into lower elevations. •Carries water from the land after rainfall or snow melts. •Drains all the water into a common outlet such as a stream channel, a reservoir, or bay Fresh Water •Very low amounts of dissolved salt – less than 1% •Examples: •Ponds and Lakes •Streams and Rivers •Wetlands •Makes up 3% of Earth’s water resources, including ice caps and glaciers Salt Water •High concentrations of salt •3.5% of the weight of seawater comes from dissolved salt (salinity) •Examples: •Oceans •Seas •Makes up 97% of Earth’s water resources Surface Water •Water on the surface of the planet •Examples: •Ponds and Lakes •Streams and Rivers •Wetlands •Oceans •Replenished by precipitation and groundwater •More prone to pollution than groundwater Groundwater •Water found underground in cracks and spaces in soil, sand, and rock. •Stored in and moves slowly through aquifers •More than 50% of the people in the U.S. get their drinking water from groundwater. •Largest use is irrigating crops Less prone to pollution Groundwater Vocabulary •Permeable – rock layers or sediments that transmit groundwater freely a.Must include spaces (pores) throughout the rock layer b.Pores must be connected •Impermeable – few or no connected pore spaces, such as clay Groundwater Vocabulary •Zone of Aeration – region between the earth’s surface and the water table •Water Table – the upper surface of the Zone of Saturation (can move up or down depending on rainfall) •Zone of Saturation – region in the ground in which the pore spaces are filled with water Aquifers •Found underground •Made of gravel, sand, sandstone, or limestone •Water can move through these materials because they have large connected spaces (pores) that make them permeable. •The flow of water depends on the size of the spaces and how well they are connected. Well •An excavation or structure created in the ground by digging, which accesses groundwater in an aquifer. •The well water is drawn by a pump that is raised mechanically or by hand. •How is the well depth determined? What might make a well “go dry?” •Replenished by precipitation Artesian Well •A place in the ground where water flows up to the surface because of natural pressure without being pumped. •Water comes directly from the aquifer or porous rock layer. •Gravity creates the natural pressure. •A place in the ground where water flows up to the surface because of natural pressure without being pumped. •Water comes directly from the aquifer or porous rock layer. •Gravity creates the natural pressure. Water Pollution: http://www.ducksters.com/science/environment/water_pollution.php •Contamination of bodies of water, often by human activity, which affects watersheds •Occurs when pollutants are discharged directly or indirectly into the water. •Along with air pollution, water pollution is the second biggest environmental concern. Point Source Pollution When the pollutants come from a single location such as dumping chemicals into a river. Nonpoint Source Pollution: https://www.youtube.com/watch?v=phmN-IpR3xw When pollutants are introduced into the environment over a large, widespread area such as agricultural runoff. Types of Water Pollution •Surface water •Oil spillage •Chemical •Groundwater •Thermal •Agricultural Overuse and Waste •Irrigation uses 30% of all freshwater in the U.S. •Swimming pools and water parks •Golf courses •Washing cars •Watering the lawn What other ways do you overuse or waste water where you live? Land Subsidence •Withdrawing groundwater causing the land to sink •Causes flooding problems •Causes a shift in the foundations of buildings, which can lead to their destruction SCIENCE 8: Explanation of forces we can't see.... |
Erik E. Mason
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