The History of Earth Video Summary
Early earth was a group of rocks in space pulled together over time by gravity. This superheated the earth, making it a large ball of molten rock (side). Over time, the earth eventually cooled down, and water was brought via asteroids that were melted. After this, primitive life began (below).
Life then began to evolve over time, as new species were made and existing ones altered for the changng environment. As catastrohpies stuck and changes occured rapidly, evoluion began to progress further. All of these changes eventually lead to the planet as we see today (bottom).
Life then began to evolve over time, as new species were made and existing ones altered for the changng environment. As catastrohpies stuck and changes occured rapidly, evoluion began to progress further. All of these changes eventually lead to the planet as we see today (bottom).
The Properties of water (worksheet)
Polarity
A molecule that has electrically charged areas is called a polar molecule. Uneven charges making one end positive and one end negative is called polarity.
cohesion
The tendency of water molecules to form weak bonds with each other is called cohesion.
ADHESION
Adhesion is the tendency of water to stick to other substances.
capillary action
The combined forces of cohesion and adhesion allow water to climb tubes against the force of gravity, as seen in roots and stems in plants.
surface tension
Surface tension is the force (weak hydrogen bonds) that keeps the surface of water together, preventing the individual molecules to separate.
specific heat
Specific heat is the amount of heat needed to increase the temperature of 1kg of a substance by 1 degree Celsius.
hydrogen bond
Hydrogen bonds are the weak attractions between hydrogen molecules in water.
water facts
The chemical formula for water is H2O. Water is made up of atoms to form molecules. Water is a polar molecule. Bonds that form between water molecules are called hydrogen bonds. Hydrogen bonds are weak and require little energy to break. The tendency for water molecules to stick to other water molecules is called cohesion. A force that acts upon the particles of a liquid at the surface is called surface tension. Surface tension forces the surface of water to curve because the weak hydrogen bonds hold the water together. The tendency of water molecules to be attracted and stick to other substances is called adhesion. Surface tension helps some insects "skate" across the surface of the water, refers to the tightness across the surface of the water, and causes raindrops to form round beads. A curved surface in a graduated cylinder is called a meniscus. Capillary action explains how water moves against the force of gravity, and is due to the attraction among molecules of water and surrounding materials. Capillary actions allows water to climb up the sides of a straw because the combined forces of cohesion and adhesion allow it to go against the fores of gravity. A solution is a mixture that forms when one substance dissolves another. The substance that does the dissolving is called a solvent. Water can dissolve many substances because it is polar. Water can dissolve substances like salt. A substance that hates or "fears" water is called hydrophobic. The amount of heat needed to increase the temperature of 1kg of a substance by 1 degree Celsius is its specific heat.
the properties of water (lab)
Evaporative cooling: #1 Water and alcohol
The water felt cooler than the water. It is beneficial that sweat is water based and not alcohol based because it takes more heat for water to evaporate. Therefore, water will take away more heat when it evaporates than alcohol, because alcohol evaporates easily, meaning it takes away very little heat.
water tension/cohesion #2 Water on a penny
The predicted amount of water drops that would fit on a penny was 20. 45 drops were able to fit on the penny, and this was achievable because of the surface tension of water, as well as it's adhesion to the penny itself.
surface tension #3 water on wax paper
The water hardly stuck to the wax paper at all. It slid across the surface without leaving any trail of water droplets. The water stayed in it's own "ball" of water because of the surface tension.
surface tension #3a Paper clips on the surface of a cup of water
The paper clip was able to float on top of the water. This is due to the surface tension of the water. When the drop of soap was added to the water, the paper clip instantly sunk.
adhesion #4 graduated cylinder
The water is not a straight line across in a glass container because of the adhesion properties of water. The water wants to stick to the glass, so it climbs up the sides of the glass container. This results in a meniscus. The water property of adhesion is important in living systems because it helps the travel of water throughout the organism, especially in plants. This is because the adhesion wants to stick to the surface, which helps water to travel against gravity.
water as a solvent #5 Dissolving
Only salt dissolved in the water. Sugar and oil did not dissolve because sugar is covalent and oil is hydrophobic due to the lipids it contains. For sugar, the water molecules took each sugar molecule away from each other and surrounded it, making it appear as though it dissolved. The oil simply floated on top of the water. The characteristic of water allows it to be such a powerful solvent is it's polarity. The polarity allows the water to pull apart other ionic systems. Two other things that would dissolve in water would be bath salts and artificial sugar, because they are ionic. Two other things that wouldn't dissolve in water would be gasoline and shampoo, because they are not ionic systems.
capillary action #6 rolled up paper towel
Capillary action is important to plants and trees because it helps them to pull the water up the roots to the top of the plant against gravity so the whole plant can be nourished.
density using salinity lab
Salinity is the measure of how much salt is dissolved into a certain volume of water. In this lab, we looked at how salinity affects density. We took four beakers and filled them with water. The first was clear and had no salt, the second was blue and had a little salt, the third was red and had a moderate amount of salt, and the fourth was green and had a lot of salt. We slowly mixed these waters into a test tube in order of density via a pipettes. As a result, the waters layered from densest on bottom to least dense on top, forming visible layers.
water bouyancy lab
In this lab, we studied the properties of the bouyancy of water. The object was to try and fit as many pennys as possible into a boat made out of aluminum foil. Different designs were able to hold different amounts of pennys because of their bouyancy. Water has weight, and because water is a liquid, whenever an object is place in water, one of three things happens: if the object is lighter (less dense than water), the water pushes up from underneath and the object floats. If the object is heavier (denser than water), it overcomes this force and sinks. If the object has the same density, it will simply float around with the currents of the water. Foil is less dense than water, so it floats. As the pennys are placed in the boat, however, it increases the weight, making the volume that the boat is taking up in the water more dense, and it gradually sinks as more weight is added. Different shapes take up that same volume differently, some making more use of the volume and some less.
Density, Temperature and Salinity
The ocean is a vast, extensive system that spans the entire globe. Within this system are currents that extend just as far as the ocean. These currents are driven by three major factors: density, temperature, and salinity. Density is how much weight water has compared to it's volume. Denser water sinks to the bottom. Temperature is a factor because cold water sinks and warmer water rises to the top. Salinity is the measure of how much salt is dissolved into water. Saltier water sinks to the bottom. All of these factors combine to create layers of differentiated values which drive the ocean currents. These currents circulate the globe seeking equilibrium in water conditions, though since water is always being recycled and temperatures change over day and night, the currents always continue.
bill nye - oceanography
stagnant salt
Heat from the sun makes the water in the ocean evaporate but the salt stays in the ocean because salt does not evaporate.
saltless rain
There is no salt in rain because the salt is not evaporated, therefore it cannot be in the rain.
heavyweight
Salty water is heavier than freshwater because there is dissolved matter in it making it denser.
warm tea
Water helps keep England warmer because of warm water currents that come up from the south.
current currents
A current is a river of water flowing through water.
Thermohaline currents...
Thermohaline currents are driven by different values of heat and dissolved salt.
Data marker bouys
Data marker bouys are used to track ocean currents
Aquarium life
Fish in aquariums need currents so they can get food and water (with oxygen).
Salty lakes
The Great Salt Lake and the Dead Sea are salty because they have no connection to the ocean to flush out their minerals.
sunburn
The uneven heat in the water causes certain parts of the water to be less dense, so the lighter water and heavier water move around trying to find equilibrium.
Strong water
The Atlantic Ocean has the most powerful current in the world.
misunderstood mars
Mars can't have oceans because Mars is too cold, so the water would freeze.
The circle of life
Many things depend on currents for transportation, food, and suitable climates, such as fish and algae.
Currents
Current info
Currents are basically underwater rivers driven by winds, temperature, salinity and gravity. They differ greatly in size.
The gulf stream
The Gulf Stream Current is simply a warm water current in the North Atlantic ocean. It is a very old and very large current.
Causes of currents
Currents can be caused by winds (friction) gravity (pull) and differences in density, which can be caused by differing temperatures and salinity.
Surface circulation and deep circulation
Surface circulation is the movement of water on the surface of the ocean in a thin layer. Deep circulation is the movement of water that is in the lower portions of the sea, sweeping along the sea floor.
GYres
A gyre is a current on the surface of the ocean (surface circulation) that is well organized, roughly circular, and driven by winds and gravity. They bend around the earth's continents and rotation. There are 5 major gyres: two in the Atlantic, two in the Pacific, and one in the Indian ocean.
Factors of surface currents
Wind is a very important factor in surface currents. As they blow across the surface of the water, they drag the top layer of water along with the wind. As this continues, that top layer of water drags the layer below it, and so on. As the current deepens, it slows down considerably, until it dies out. Gravity is also a large factor in surface currents. Along the globe, there are "hills and valleys" on the surface of the water, and gravity pulls water down these "valleys" to balance out the levels.
Summer tropics
In the summer, an interesting phenomena takes place in the tropics. Though not visible to the naked eye, the heat of the summer sun warms the tropic water, which causes it to expand. There is then a bulge around the equator of warm water.
Coriolis effect
This effect causes currents to flow at an angle from their cause (such as wind) because of the earth's rotation. The surface of the earth travels faster at the equator than at the poles, influencing all objects loosely in contact with the ground, such as currents, wind and airplanes.
Coriolis and planes
Because of the Coriolis effect, planes traveling north or south have to head to their destination at an angle, allowing for the increase or decreased speed of the surface of the earth.
coriolis and currents
Because of the Coriolis effect, currents veer to the east or west depending on the hemisphere they're located at.
Gulf Stream details
The Gulf Stream is the strongest, deepest, and fastest part of the North Atlantic Gyre. It warms up the northern part of the Atlantic because of its vastness. It takes 10 years for it to make a full rotation.
El Nino
The equatorial counter current that travels east is very warm, which contributes to the El Nino weather phenomena.
Temporary currents
Temporary currents include longshore, rip, and upwelling currents. These currents last a very short time and are driven by the seasons or the weather.
longshore currents
Longshore currents flow along shorelines where waves hit the beach at an angle. This causes beaches to disappear as the current carries the sand and fill in harbors with the sand.
Rip currents
Obstacles channel water away from the shore line as wave beat the beach. This current is particularly dangerous and can carry people out to sea.
Upwelling currents
Wind pushes surface water away from shore, and deeper water rises to fill the gap created by this. This brings nutrients to the surface and helps plant and animal productivity.
Gloval conveyor belt
The Global Conveyor Belt is a huge, strong underwater current spanning the entire globe. It slowly empties one ocean into another over time.
Thermohaline Circulation
Thermohaline circulation drives the heavier water down and the ligher water rises, causing currents. Cold and salty water is denser, and warm water with less salt is lighter. This is the major driving force of the Global Conveyor Belt.
currents and humans
Currents partially regulate globa climate in terms of temperature, as the temperature from the ocean leaks out into the atomosphere. They also greatly influence the productivity of fishing grounds.
Upwelling and people
Upwelling currents take up about 10% of the world's oceans, but account for half of the world's fisheries. They support the base of the food chain (plankton, ect.) which leaks up to help clams to fish and the things we eat.
OCeAN CURRENTS AND CLIMATE
Warm Western boundary currents carry tropic heat from the south to the poles, warming the atmosphere in those areas. Cool Eastern boundary currents carry polar cold temperatures to tropic waters. This temperature regulation is what keeps most of Western Europe warm enough to inhabit comfortably, compared to other places at it's latitude, such as Alaska.
global warming and the currents
Excess rain in the poles could block cold salty water from sinking, which would halt current flows in that area, and start a chain reaction. This could shut down the Global Conveyor Belt, and European temperatures would fall on average 10 to 20 degrees Fahrenheit.
waves
Molecules in waves
Individual water molecules in waves do not travel in waves, but rather move in circles as the wave passes. The molecules move most on the surface, and the water molecules move in smaller circles as the wave deepens.
wave movement
Waves do not transmit water across the ocean, but energy.
Wave anatomy
The highest part of the wave is called the crest. The lowest part is called the trough. The distance between the crest and trough is the wave height. The distance from crest to crest is the wavelength.
Wave generation
Most waves are generated by wind.
Max waves
Waves reach their maximum size when they nearly match the speed of the wind pushing them.
Largest waves
The largest waves on earth are found in the open oceans between Antarctica and the Indian Ocean, because the wind travels the longest and fastest with the least amount of land resistance.
Wave train
A wave train is a group of wind driven waves that are stacked behind each other.
Rogue WAve
A rogue wave is a freakishly large wave caused by the focusing of waves, such as when wave trains collide, and can reach 100ft.
Shallow waves
When waves reach shallow water, the bottom of the wave meets the sea floor, and the wave slows down, shortens wavelength, and heightens, as the energy is forced to the top. The bottom of the wave slows down faster than the top of the wave, causing the to break.
Swash
Swash is a foaming sheet of water formed from crashed waves. These contribute to erosion, as they carry sand to, away from, and around the shore.
Tsunami
A tsunami is a huge wave caused by underwater landslides, volcanic eruptions, asteroids landing in the ocean, and most of all, earthquakes. Tsunamis are different from regular waves because they are much lower, far faster, and wider. An estimated one million people have been killed from tsunamis.
tsunami protection
Warning systems for tsunamis as well as common sense from people can help save lives from tsunamis. Government placed buoys can detect tsunamis from far off, and there are also ways to detect them from land. Before a tsunami hits, the water line recedes dramatically from shore. Animals also tend to leave the area.
electricity from water
Generator designs are being developed that rely on the up and down motion of waves to spin turbines. It is predicted that the possible electricity that could be harnessed from the ocean's waves may be twice that of which the entire world currently consumes.
bill nye: waves
wave information
Three things travel in waves: energy, light, and sound. Waves have three properties: amplitude, frequency, and wavelength. Amplitude is the height, or depth, of the wave, from the top to the bottom, or from peak to peak. Frequency is the rate at which the peaks of the waves travel a given point. Wavelength is the distance between two wave peaks in a wave train. Not all waves go up and down, however. Some move in a compression motion, such as sound waves. Sound waves are used in sonar. Sonar is the sending of a specific frequency of sound wave, and listening for the echo. The longer it takes the echo to return, the further away the object is. When a wave is bounced back and is returned to the source, it is "reflected".
Wave types
Light waves in different wavelengths appear in different colors to our eyes. When light is run through slits, they break into patterns because the different wavelengths separate. X-rays have a much higher frequency than light waves, and therefore carry more energy.
tides
Turn of the tide
Tides are the regular alternating rise and fall of sea level, noticeable on shorelines. The gravitational pull of the moon and the sun cause the tides. Tides occur in oceans, large lakes, an in some places even solid landmass. High tide is the highest normal point at which the water peaks during the day, and low tide is the lowest normal point to which the water drops during the day.
affecting the tides
The moon has the greatest force on the tides. While the sun is 26 million times larger, the moon is 400 times closer, and therefore has the greatest hold on our oceans. However, when the sun and the moon align, they create very strong tides, called spring tides. When they are perpendicular, they create very weak, low tides, called neap tides. Other factors that affect the tides are wind and weather, the earth's rotation, coastline shape, seafloor topography, and river discharge.
critters in the tides
The zones of the intertidal zone are the spray zone, which is usually splashed and rarely submerged, the upper intertidal zone, which is only underwater during high tide, the mid intertidal zone, which is mostly submerged and only briefly dry, and the low intertidal zone and subtidal zones, which only get air during low spring tides. There are quite a few challenges for the animals that live in these different zones, such as the possibility of drying out, temperature extremes, intense sunlight, a wide range of salinities, and predation. These organisms have come up with a variety of ways to cope, however, including tough, leathery leaves and growth in bunches (seaweed), crowding together, scrunching up and utilizing mucus coatings (anemones), closing tightly to conserve moisture (shelled fish), and mobile animals retreat, borough, hide in rocks and plants (crabs/fish). To combat the action of waves in these zones, sea stars have thick skin, a tough skeleton, plus suction feet. Low tidal plants sway easily, while the roots are very strong. Sea slugs have one large foot to hold on tightly to rocks. Clams and mussels have thick shells and cement themselves to each other and rocks. Fish in these areas have very sturdy bodies, strong muscles.
Global impact of the tides
The physical impact of the tides are redistribution heat and nutrients, regulation of climates, and about half of the power needed to move the "global conveyor belt" comes from tides. While they help tremendously in some areas, they can be challenging in others. They can worsen storm and tsunami damage, and can majorly affect human activity, including building, planning, and sailing. However, some people are trying to harness this power and turn it into electricity, using the up, down, and sideways motion of the tidal currents using turbines.
Predicting the Tides
It takes six hours and twelve-and-a-half minutes to go from high tide to low tide, and twelve hours and twenty five minutes to go from one high tide to the next. Spring and neap tides are created by either the fighting or joined forces of the sun and moon. Due to the rotation of the moon around the earth, two spring tides and two neap tides occur each month. Distance of the sun and moon affect the tides because of their gravitational pull, which weakens with distance. Tides are higher at perigee, which happens once a month. Solar tides are higher at perihelion, which happens once a year.
Life in the intertidal zone
There are a wide variety of different organisms all across the tidal zones, though it is highest in the lower zones and smaller in the upper zones. Organisms above average sea level run the risk of dehydration and predation, though below this zone waves and currents are a large hazard. In the upper zones, many animals have shells or are able to move away from the waves. In the lower zones, many organisms are able to attach themselves to objects and are either very sturdy or flexible to accommodate wave energy. Even though it is a dangerous area, many animals inhabit this place because there is very low competition, and there is a lot of light for photosynthesis.
energy from the ocean
power of the ocean
Renewable power can be generated by the ocean by the mechanical and thermal energies of the ocean. The up and down motion of tides and waves as well as pressures and lateral flow of water could power generators and turn turbines. However, wave energy is not considered to be a reliable energy source because wave size, speed, and direction vary greatly. It would be best to set up wave-power plants on western coastlines in mid-latitude. The up and down motion of the tides, as well as lateral flow, could power larger turbines and generators, and is much more reliable. However, only areas with very large tides could harness such energy. OTEC (Ocean Thermal Energy Conversion) uses seawater to turn thermal energy into electricity. Using the thermal gradient of water (warm surface water and cool deep water) plants could use the thermal changes to evaporate and condense ocean water for energy. However, there needs to be a 20 degree (Celsius) difference in surface and deep water within 1000m for it to be possible. Such conditions exist in tropical waters. Some benefits of OTEC are that the cold water is nutrient rich and could be used for agriculture and aquaculture, air conditioning, and refrigeration. When ocean water is evaporated and condensed, it becomes desalinized (salt is removed) and can be used for drinking water. However, OTEC is more expensive and less efficient that traditional methods, and could have an impact on coastline processes and wildlife. Some non-renewable energy sources currently in the ocean include oil, natural gas, and methane hydrates. Microscopic algae fall to the sea floor, are buried, liquified, and vaporized by the pressure of the sediment above, and these become oil deposits. Off-shore petroleum is more expensive and difficult than land petroleum, but is less expensive than alternate fuels. Methane hydrates are molecules of methane frozen in a cage of water. Bacteria break down organic material, and high pressures coupled with low temperature causes this methane to freeze into enormous crystal deposits. Extraction however is very difficult and dangerous, as the deposits could explode, or disintegrate causing underwater landslides, and releasing vast amounts of methane gas (a greenhouse gas) into the atmosphere.
global impact
Off-shore petroleum provides 30% of the world's oil and 50% of the worlds natural gas. Methane hydrates could produce 10's or even 100's of years of energy.
in depth: methane hydrates
Methane hydrates are found in the permafrost of Arctic regions. If sea level were to rise, form warmer temperatures causing the melting of glaciers and snow, the permafrost would warm up and release methane gas. If global temperature averages were to fall, methane gas would be released and the global temperature would rise, since it is a greenhouse gas. If it were to escape in vast quantities into the atmosphere, cooling trends would slow down or even reverse. In the Ice Age, it is possible that as sea temperature dropped, methane gas could have been released, causing global warming, and melt away the ice. Methane hydrates, if melted and released, could intensify global warming, making it hotter and quicker.