Environmental Sciences Study Guide PDF

Study Guide Main Topics: The Four Spheres Absorption ○ EM Radiation ○ Bonds (electrons) Biogeochemical Cycles Feedback Loops ○ Positive + Negative ○ Albedo Model of What Happens When I Flick a Lightswitch Chemistry ○...

Study Guide Main Topics: The Four Spheres Absorption ○ EM Radiation ○ Bonds (electrons) Biogeochemical Cycles Feedback Loops ○ Positive + Negative ○ Albedo Model of What Happens When I Flick a Lightswitch Chemistry ○ Chemical Equations ○ Balancing Chemical Equations ○ Atoms ○ Bonds Earth’s Four Spheres: The four spheres of Earth include the: ○ Lithosphere: the rocky other part of Earth (“land”) ○ Hydrosphere: the total amount of water on a planet (“water”) ○ Biosphere: includes all living organisms (the region where organisms live) ○ Atmosphere: gasses that surround the Earth (“air) Biogeochemical Cycles: Biogeochemical cycles are divided into two parts: ○ Gaseous: which includes carbon, oxygen, nitrogen, and the water cycles. ○ Sedimentary: which includes the sulfur and phosphorus cycle Carbon Cycle: How carbon travels through different reservoirs on Earth. Carbon travels through the atmosphere, to plants, to animals, and back. Steps: ○ Carbon present in the atmosphere is absorbed by plants for photosynthesis. ○ These plants are then consumed by animals and carbon gets bioaccumulated into their bodies. ○ These animals and plants eventually die, and after decomposing, carbon is released back into the atmosphere.  ○ Some of the carbon that is not released back into the atmosphere eventually becomes fossil fuels. ○ These fossil fuels are then used for man-made activities, which pump more carbon back into the atmosphere. Oxygen Cycle: Circulation of oxygen in various forms throughout nature Steps: ○ All green plants during the process of photosynthesis, release oxygen back into the atmosphere as a by-product. ○ All aerobic organisms use free oxygen for respiration. ○ Animals exhale Carbon dioxide back into the atmosphere which is again used by the plants during photosynthesis. Now oxygen is balanced within the atmosphere. Nitrogen Cycle: Process in which nitrogen is converted into many forms (passes from atmosphere to soil to organisms and back into the atmosphere) Steps: ○ Nitrogen Fixation: The process of converting N2 into biologically available nitrogen ○ Nitrification: The process that converts ammonia to nitrite and then to nitrate ○ Assimilation: the process by which inorganic nitrogen compounds are used to form organic nitrogen compounds such as amino acids, amides, etc. ○ Ammonification: Various fungi and prokaryotes then decompose the tissue and release inorganic nitrogen back into the ecosystem as ammonia ○ Denitrification: the process that converts nitrate to nitrogen gas (removing bioavailable nitrogen and returning it to the atmosphere.) Water Cycle: The continuous movement of water within the Earth and atmosphere Steps: ○ Evaporation ○ Condensation ○ Precipitation ○ Sublimation ○ Transpiration ○ Runoff ○ Infiltration Sulfur Cycle: Movement of sulfur through the geosphere and the biosphere Steps: ○ Decomposition of Organic Compounds ○ Oxidation of Hydrogen Sulphide to Elemental Sulphur ○ Oxidation of Elemental Sulphur ○ Reductions of Sulphates Phosphorus Cycle: Describes the transformation and translocation of phosphorus in soil, water, and living and dead organic material. Steps: Weathering Absorption by Plants Absorption by Animals Return to the Environment through Decomposition Model of What Happens When I Flick a Light Switch When you flip a light switch off: When you turn off the light switch electrons inside the wire cause a “domino effect” in which the electrons stop producing electricity Voltage goes down Send signals to the powerhouse When you flip a light switch on: The circuit goes on and then sends a signal to the lightbulb The electrons start producing electricity Send signals to the powerhouse The powerhouse starts producing more electrons which transfer back to the light switch 1. When You Flip a Light Switch Step 1: Turn the light switch on Step 2: The filament in the light bulb creates electrons Step 3: The electrons push each other causing a "domino effect" and produce light This informs the powerhouse that you have turned on a light switch. In turn, the powerhouse creates more electricity. When you turn off the light switch it causes the electrons to bunch up and stop producing energy. This is a negative feedback loop because once you turn on the light, you will eventually turn it off. The loop ends where it first began. 2. Heater System: You turn on the heater when the weather is cool. The heater causes the temperature to rise. Then the temperature is too hot so you turn off the heater. And now the temperature is cold again. This is a negative feedback loop because the input and the output are stable. The loop ends where it first started. Positive (Reinforcing) Loop: A positive feedback loop is when the input is increasing and the output of the loop causes instability. Negative (Stabilizing) Feedback Loop: A negative feedback loop is when the loop ends where it started. A positive feedback loop causes stability. For instance, when you turn on a heater it causes the temperature to rise, but when you turn it off the temperature decreases. Now, it's cold so you have to turn on the heater again. MODEL OF FEEDBACK LOOPS ALBEDO: Amount of light a surface reflects The darker the surface is the less light is reflected (low albedo) SHOULD WE GO TO MARS? I think that humans shouldn't go to Mars. To start with, traveling to Mars requires a lot of patience and is pretty expensive. For instance, we need enough money for shelter, transportation, and other necessities. Even if we had that kind of money, it would be nearly impossible for all human life to go to Mars. Higher-income families would be more likely to visit Mars which would be an injustice to middle and lower-class people. Additionally, humans don’t have enough information regarding Mars and it will take a lot of effort to make the planet habitable. Instead of relocating to another planet, we should eliminate problems that cause harm to Earth. ABSORPTION + EM RADIATION Imagine yourself on a hot summer day. You have a large rock of black obsidian and a large white quartz rock. The sun has set, and you put your hand on the two rocks. Identify which rock is warmer. The black obsidian rock will be warmer because it absorbs all of the Sun’s energy causing its temperature to increase. Additionally, the black rock will stay warm the longest because of all the stored energy inside of it. Black: Absorbs Light White: Reflects Light Notes: Light is also known as ELECTROMAGNETIC RADIATION Electromagnetic radiation comes in varieties of wavelengths Limited number of wavelengths humans can see ○ Such as visible light (only light we can see) ○ Does not need a medium to travel ○ Light does not experience time ○ Light isn’t matter You cannot have heat without matter When you turn on a light the powerplant burns fossil fuels The mill spins a magnet The wire is being spun, making the electrons move Matter absorbs molecules (electrons) The electrons are interacting with the light Absorption: light is being “soaked up” by an object Reflection: light bounces back Chemical Equations:  Expression that gives the identities and quantities of the substances involved in a reaction Reactants on the left and product on the right Balancing Chemical Equations: Number of the atoms involved in the reactants side is equal to the number of atoms in the products side. Covalent Bonds: Occur when two or more atoms share electrons. Ionic Bonds: Has ions (contain both + and - charges) Created by a transfer of electrons Polar Covalent: Electrons are shared unequally Nonpolar Covalent: Electrons are shared more evenly