Global Winds

Global Winds by Arianna Valdes :)

Global winds are a very complex thing to get a grasp the concept of. They are formed by unequal heating on the earth. The most direct sunlight in on the equator and the least direct sunlight in on the poles of the earth. So therefore the equator has low pressure and is less dense and the poles a have more high pressure and is more dense. So because of the unequal heating and convection currents form. Also there are wind belts called the trade winds, the prevailing winds and the polar easterlies. The wind belts are the winds that basically separate the convection currents from each other. The trade winds start off in the equator and go to 30 degrees north and south.The prevailing winds are wind move from 30 degrees north and south and move to 60 degrees north and south. Finally the polar easterlies move from 60 degrees north and south to 90 degrees north and south (which are to the poles). Also there is an area called the doldrums were the warm air rises from the equator, it is a very calm area around the globe. There would be no curving belts if the earth didn’t rotate though. It would be very straight and boring.

http://deckskills.org/sitebuildercontent/sitebuilderpictures/global_wind_diagram.jpg

You may have heard the phrase Coriolis Effect before but never knew what it meant or was. Well, hopefully my summary clears up any confusion for you guys. It is the effect that makes the wind blow over the Earth in a certain direction. So the reasoning why, is when you are flying you can’t just move in a straight line, because of the rotation of the earth. This is because the earth is rotating while you are flying, so you need to plan your flight with the Coriolis effect. In the northern hemisphere the path moves right from where the wind comes from and in the southern hemisphere the path moves towards the left from where the wind comes from. 

http://www.pinellascounty.org/newsletters/e-lert/images/feb_2010/coriolis-effect.jpg

On a cylinder the side of it all has equal heating from the sun which causes low pressure through-out the sides and high pressure at the top and bottom. In the center the low pressure warm air rises up and up towards the top and once it reaches the top the air sinks because the air gets cooler and has more density and circles back to the middle. The same thing happens in the southern hemisphere just reversed. The cool air sinks and the warm air rises back to the middle. So there are 2 convection currents being formed on a cylinder because of the unequal heating on the top and bottom. So a cylinder shape is close to the earth but there are some major differences. 
  

A cube unequal heating on the top and bottom. It is sort of like the cylinder but it is a little different. The top and the bottom have high pressure and cool air and the other 4 sides have low pressure and warm heating. Also the winds blow towards each other while they are spinning. There is one big blob of a convection current circling around the cube hitting all the sides.

On a pyramid is a little more complex than the rest though. At the top of it is just a single point so there is really no effect on that. But along the side of the pyramid there is equal heating and direct heating which leads to warm air and low pressure. The bottom of the pyramid is flat and has cool air and high pressure. Since there is only one unequal heating source the warm air moves towards the bottom were the unequal heating is and then slides over the pyramid and goes back to the being. So it is one big convection current. This one is probably farthest away from the shape of the earth.   

Here is a good video to help you guys deeper understand global winds.

http://www.youtube.com/watch?v=mi6F1PdXUPM

Local Winds by Cara Jones

Local winds are winds that only go short distances.  They occur when air wants to move from high to low pressure areas. Wind speed varies depending on how different the temperatures are. This means if there is a difference of 10 degrees the wind speed is going to be less than and temperature different of 20 degrees.

A sea breeze is a wind that blows from the sea to the land. During the day the sun gives off radiation. When it does the land and ocean both absorbs it’s heat but different amounts. The land heat up and absorbs the heat faster than the ocean because the land doesn't reflect or refract the heat or the light. like the ocean does. When the land is heated up it uses conduction to heat up the air molecules around it. The air molecules are not as heated over the ocean because there is less heat to conduct. This difference in air temperature causes the warm air over the land to become less dense and rise, causing low pressure. While this is happening the cooler, denser air of the ocean is sinking, creating high pressure. Then using convection the winds form.  Then to create the convection we know the air molecules like to go from high to low pressure.

A land breeze is a wind that blows from the land to the sea.  During the night there is no heat source so all of the heat in the surfaces  was absorbed the day before.  The ocean holds on to the little heat it collects better than land. This makes the ocean hotter than the land at night. Because of this, the winds switch creating a breeze that goes from land to the sea.  Like with a sea breeze the heat in the ocean and land heats up the air molecules with conduction. The air on top of the ocean is warmer than the air above the land.  This also means the air on top of the ocean is less dense and has a lower pressure than the air above the land, making the molecules want to go from the land out to the sea.

There are no convection currents at sunrise and sunset because the land a the sea are the same temperature. They heat the molecules above them to the same temperature and there is no less dense place for the molecules to go and therefore no convection current.

Mountain Breeze and Valley breezes are another type of breezes.  A valley breeze is a breeze that happens during the day and goes up the mountain. A valley breeze occurs when the sun heats up the valley and using convection heats up the molecules around the heated land. This causes the warm, low pressure air to rise as the high pressure and cold air push down from the sky.
A mountain breeze is a breeze is a breeze that happens at night.  This breeze happens when the valley is cooling but is still heating the air. This time the air goes straight up the middle because the sides around it are already cool and come down to fill in the space the low pressured air left behind.

This is a Mountain Breeze
http://innovationcharterschool.wikidot.com/mss:king-land-breeze-sea-breeze-mountain-breeze-and-valley-b

 

This is a Valley Breeze http://innovationcharterschool.wikidot.com/mss:king-land-breeze-sea-breeze-mountain-breeze-and-valley-b


This is a video to help your understanding about Local Winds

Earthquakes by Izzy Essi

Earthquakes are caused by the movement of plate tectonics from convection currents in the mantle. When the plates move they are either converging at a convergent boundary or diverging at a divergent boundary. Converging means that the plates collide and diverging means the plates pull apart. These forces that cause the plates to move are examples of stress. The stress and energy is stored into the rock until the rock eventually breaks. Shearing, tension, and compression are three different types of stress that change the shape of a rock. Shearing is when rock slips past each other in different directions, causing the rock to slip and break apart or change its shape. Tension is when rock is slowly tearing or stretching apart making the middle thin. Compression is when the rock is pushed together or squeezed until the rock folds or breaks.

The plates are also moved by the convection currents in the mantle. Inside the Earth, in the asthenosphere are convection currents heated from the Earth’s core and the mantle below the asthenosphere. When convection currents move towards each other, it causes the plates to move towards each other at a convergent plate boundary. If the convection currents move away from each other, it causes the plates to break apart or move even farther away from each other, at a divergent boundary. Convection currents and stress are what cause plate motion, and plate motion causes earthquakes. Earthquakes are more likely to happen near plate boundaries with tectonic motion because when the stress builds up at a plate boundary it causes a fault which is when the crust breaks, causing an earthquake.

Faults are where earthquakes mostly occur. Faults are a break in the crust which causes the Earth’s crust to move. There are four different kinds of faults; strike slip, normal, reverse, and oblique. A strike slip fault is caused by the stress of shearing. Along a strike slip fault line, the rock slides past each other sideways with little up and down motion. Strike slip faults form along a transform boundary. An example of a strike slip fault is the San Andreas Fault in California.

Another type of fault is a normal fault caused by the stress of tension.  In a normal fault the fault is at an angle so half of the rock is above the fault line and the other half is below the fault line. The half that is above the fault line is the hanging wall and the half that is below the fault line is a footwall. At a normal fault the hanging wall slides downward. Since the stress is tension, the plates diverge and break apart. An example of a normal fault is along the Rio Grande rift valley.

Reverse faults are caused by the stress of compression. The reverse fault also has a hanging wall and a footwall but they go in different directions. The footwall and the hanging wall are then pushed together in the stress of compression, causing the hanging wall to go over the footwall along the fault line. An example of a reverse fault is in the majestic peaks at the Glacier National Park in Montana.

The last type of fault is an oblique fault. An oblique fault has two types of stress of shearing and tension, which occur at the same time. The motion of this type of fault is a normal fault and a strike slip fault combined. So the hanging wall slides down the the fault line while the footwall and hanging wall slide past each other.

Strike Slip Fault

http://michaelgivens84.edublogs.org/ch-11-science/

Normal Fault

http://www.williamsclass.com/SixthScienceWork/FoldFault/FoldFaultGeologyNotes.htm

Reverse Fault

http://nees.cornell.edu/education/level1pages/level2pages/reverse.html

Oblique Fault

http://scec.usc.edu/internships/useit/eqbasicinfo

Seismic waves carry the energy from the focus of an earthquake and go through Earth’s interior and across the surface. The focus of an earthquake is where the rock actually breaks along a fault line. The epicenter of an earthquake is when the seismic waves reach the surface of the Earth. There are four different types of seismic waves, P waves, S waves, Rayleigh waves, and Love waves. Every earthquake has P and S waves. P waves can travel through solids and liquids inside the Earth. P waves travel faster than S waves, so they arrive first compressing and expanding the ground in a vertical motion.

After the P waves come to the epicenter, the S waves arrive, traveling in the same path as the P waves. S waves can only travel through solids and not liquids. When the S waves reach the surface they shake it back and forth or in a side to side motion and up and down at the same time.

Along with P and S waves, there are also Rayleigh and Love waves, known as surface waves. These surface waves travel along the Earth’s surface, rather than through the Earth. Rayleigh waves make the ground shake in an elliptical motion. Rayleigh waves travel slower than Love waves. Love waves make a horizontal motion or side to side motion perpendicular to the direction the wave is traveling.

P Waves

http://www.universetoday.com/85000/p-waves/

S Waves

https://www.esgsolutions.com/english/view.asp?x=857

Rayleigh Waves

http://earthquake.usgs.gov/learn/glossary/?term=Rayleigh%20wave

Love Waves

http://allshookup.org/quakes/wavetype.htm

When you track these seismic waves you use a seismogram. A seismogram records and tracks the movements of the waves as they travel through the Earth. It mainly records the arrival times, the strength of the seismic waves, and their motion. The P wave is the primary wave, or, as recorded the first wave that arrives going faster than the S wave. The P wave has more energy recorded vertically than horizontally. S waves are secondary waves, which arrive after P waves as they travel slower. S waves have more energy recorded horizontally than vertically. The surface waves, Rayleigh and Love waves, are the strongest waves out of all of them even though they move slower than P and S waves.

Example of a Seismogram

http://www.bgs.ac.uk/discoveringGeology/hazards/earthquakes/howWeMeasureThem.html

Geologists use a moment magnitude scale to estimate how much energy was released by an earthquake. The moment magnitude scale is used to rate earthquakes everywhere no matter how big and far away they are. Before rating an earthquake on the moment magnitude scale, geologists must study the data from the seismogram. When they study this data they can figure out what seismic waves were produced and how strong they are. They also try to figure out what motion occurred along the fault line and the strength of the rocks when they broke along the fault line. When geologists gather all of this information they can rate the earthquake on the moment magnitude scale. They rate the earthquake on the moment magnitude scale using numbers. If they rate the earthquake a 5.0 or below on the moment magnitude scale then the earthquake was small and had little damage. If the earthquake was above a 5.0 then it caused a lot of damage. A magnitude of 6.0 produces 32 times as much energy than a 5.0 magnitude, and almost 1,000 times as much energy as a 4.0 magnitude earthquake.

Subduction zone earthquakes are normally the most destructive and dangerous earthquakes. They occur at a converging plate boundary, causing a lot of the stress to build up before the fault breaks from the pressure of two plates colliding, which is why it’s so damaging. A subduction zone is when an oceanic plate and a continental plate converge and the denser oceanic plate subducts into the mantle. Subduction zone earthquakes can often create tsunamis if they’re located on a coastline.  The continental plate overlies the oceanic plate and they get stuck together because of high friction and the continental plate drags backwards. The thin layer above the oceanic plate gets scraped off of the plate and onto the ledge of the continental plate creating a wedge of ocean sediments and seamount. The continental plate responds to the stress building upon it with the coast range rising and the inland subsiding, while the oceanic plate is still subducting. Over a long period of time the overriding continental plate will go through elastic rebound pushing the plate outward into the ocean causing a large earthquake and tsunami. The tsunami occurs because the ground beneath the ocean is displaced from the elastic rebound. As the depth of the ocean increases the wave speed and wavelength increase as well. When the wavelength increases the wave amplitude decreases. When the tsunami travels towards the shore, its wavelength shortens causing the amplitude to grow.

Subduction Zone

http://www.webanswers.com/science/earth-sciences-geology/what-type-of-tectonic-plate-boundary-sometimes-has-a-subduction-zone-395c8e

Tsunami Wavelength and Amplitude from Ocean to Shore

http://www.sms-tsunami-warning.com/pages/wave-shoaling-process#.UUfGs6V8vdk

Along subduction zones the earthquake depth can vary. The farther the earthquake is from the subduction zone, the deeper the earthquake. Meaning the closer the earthquake is to the subduction zone, the shallower the earthquake. Earthquakes only occur on the plate that is not subducting into the mantle. If you wanted to know the slope of the subducting plate you would take the depth of the center of an earthquake and measure the distance from the focus of that earthquake to the ocean trench.

Diagram of Earthquake Depth Along Subduction Zones

http://blogs.agu.org/mountainbeltway/2011/03/11/japan-m8-9-quake-tsunami/

Here is a short animation to give you a better understanding of how earthquakes cause tsunamis.

http://www.youtube.com/watch?v=qQ9Mw_rtDng

HEAT TRANSFER by Brad Litchfield

Heat can be transferred by radiation. Radiation is the transfer of heat through empty space by waves. In class, we did an experiment with a black can, a silver can, and a lamp. We put water in each can and lit the lamp, recording the temperature of the water in each can as time went on. We left the lamp shining on the cans for 10 minutes then recorded the results. The temperature of the water in the black can was greater than the temperature of the water in the silver can. This tells us that different colors absorb heat differently. For example, the black can’s water had a greater temperature because the color of the black can absorbs all of the heat. The silver can’s water wasn’t as hot because the silver color doesn’t absorb all the heat that black does, that’s why it’s a lighter color, not dark, like black.
Because different materials and colors absorb heat differently, the Earth’s surfaces are also heated differently. Because of this, dark surfaces get hotter faster than light surfaces. This is why water heats slower than land, because it is a lighter surface.
The weather on Earth is also caused by radiation. The Sun warms the planet, drives the hydrologic cycle, and makes life on Earth possible. The amount of sunlight received on Earth’s surface is affected by the reflectivity of the surface, the angle of the Sun, the output of the Sun, and the cyclic variations of the Earth’s orbit around the Sun.

  Electromagnetic spectrum            Sun heating the Earth by radiation
http://www.cernea.net/wp-content/uploads/2010/09/ElectromagneticSpectrum.png http://www.geography.hunter.cuny.edu/tbw/wc.notes/2.heating.earth.surface/images/incoming.soler.rad.budget.jpg

Heat can also be transferred by conduction. Conduction is the transfer of heat by physical contact, or solids. When heat is being transferred from an object to another, the molecules start heating up, which makes them move faster. It starts off as the heat source making molecules near it move faster, which makes molecules near those molecules move faster, and so on, until the whole object’s molecules are moving faster and the object is hotter. One day in class, we watched a video called Eureka. In the video, there were witches with broomsticks stirring a pot of hot liquid. The witches all burnt their hands because of the conduction that was happening. The hot liquid was heating the broomsticks which had that ripple effect and made all the molecules in the broomsticks speed up and get hotter. Conduction also has a role in the weather on Earth. Conduction refers to how well a substance absorbs heat & lets it go. So, for instance, water (oceans, lakes) take a long time to heat up & cool down. They in fact will regulate the temperature in areas so that in the winter it is warmer (vs. same latitude places) and in the summer it's cooler. Air molecules will conduct through different surfaces differently. The surface needs to be able to have the molecules speed up when bumped into by other speeding molecules to make it warmer.

Conduction transferring heat from source to hand             Conduction in the atmosphere.
http://www.spectrose.com/wp-content/uploads/2012/12/heat-transfer-modes.jpg
http://forces.si.edu/atmosphere/images/media/library_022_lg.jpg
Convection is the transfer of heat by liquids and solids that flow. An example of this is the outer core heating the mantle. The outer core, which is a liquid heats up and also heats the mantle, which is a solid that can flow. Changes in temperature and density happen when convection is occurring. Warm, less dense air rises and cooler, denser air sinks, causing winds to form. Another thing we did in class was the smoke box lab. For the smokebox lab, we had a box with two tubes sticking out of the top of it. There was a lit candle and also incense inside of the box. What happened was the smoke rose out of the right tube, but not the left tube. This is because the warm air and smoke, which is less dense was being pushed by the cold, more dense air, which was sinking into the left tube. The cold air sank into the left tube and the warm smoke rose out of the right tube. It was cool because you could see the convection currents of smoke in the box. Convection also plays a role in the Earth’s weather. Due to its role in heat transfer, natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be seen as clouds, with stronger convection resulting in thunderstorms.

      Smoke box lab Convection currents in the atmosphere
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieTacGfbVTCqb8dTvdr_vM9oNdotwwmFP_h7K12gSIrLLofk4ozlabr-P9CHwSY5bxaCQIzMh3sLA2dKYDj_9jGehb69-SW4CZrvBDsEb_9VjXGkenGVbHnRckUXZM3pwz2pTijZDYpj84/s1600/convenction+Investigation+3A+earth+science+010.JPG
http://www.ucar.edu/learn/images/fastcirc.gif



Indeed

Air Pressure by Tony Park

Do you know what air actually is. NO.... thats what I thought. Get ready to learn all about the stuff around you everywhere you are. First of all its air has many basic properties. It takes up space, has mass thats measurable, it exerts pressure basically everywhere, and it has a temperature.  Air is a mixture. It is a mixture between these main chemicals. Nitrogen, oxygen, water vapor, argon, and carbon dioxide.  Air pressure is the amount of force exerted onto a surface by the air molecules.  As you go up higher in the atmosphere, the air pressure decreases more and more. This occurs because air is matter and gravity forces it to be pushed down. Therefore, there is much more density of air near the bottom of the atmosphere and less and less as you go up the atmosphere. There is more air molecules at the top and less at the bottom.

(Column of air with "visible" air molecules)            (Graph of altitude (atmosphere) vs air pressure)
https://www.itslearning.com/main.aspx?CourseID=848 http://www.npl.co.uk/upload/img_400/Altitude_vs_Pressure.gif

Like I said before, air pressure is the amount of force exerted onto a surface by the air molecules.  In class we did an experiment of putting water in a cup then putting a card to seal the cup of water and flipped it upside down. We discovered that the water and air inside the cup stayed inside when held upside down. The reason for this was because of air pressure. There was air pushing down from the cup pushing at the water and cup but outside of the card, air pressure was also pushing back at the cup and equaled the same pressure. The air pressure equaled the pressure inside so the card stayed the same and the water inside and air inside could not come out or air get in from outside. When we put a pin at the top of the cup, the water released. This was because the air pressure released at the hole where the pin was and therefore, broke the seal of air pressure collapsing the air pressure outside going at the cup so the water escaped the cup.

Cup with index card.  Purple arrow showing air pressure. (blue dots water molecules purple dots air molecules)
Original picture and drawing by Tony Park

In class we did a demo of having an aluminum can of water being heated up. Once hot enough, Mr. Battaglia put it in a pan of cold water and the can seemed to make a whooshing sound and basically collapsing inside itself.  The reason for this was because of the magnificent air pressure once again!  First, the can has air and water inside of it. These two things are pushing the air pressure on the outside that is forever pushing inwards and outwards at the same force making it stay normal. As the can heated, the air molecules moved faster and expanded out of the can. Water vapor then fills the can as the water evaporated. Once the can with the water vapor hit the water upside down with the opening in the water, the water vapor in the can condensed instantly creating a partial vacuum. The extremely low pressure of the partial vacuum inside the can made it possible for the pressure of the air outside the can everywhere to crush it inside.

Diagram of the four steps showing the can collapsing Original picture and drawing by Tony Park

In class, we did an experiment where we tested trying to drink water with straws in different ways. The first example of was when we one of our classmates drank water from a cup with a straw like a regular person. The sip was like a vacuum where the water is being sucked up. Because of this vacuum, the air pressure above the water in the cup helped push the water down and into the straw. The next trial was when our classmate once again drank water from a cup but with two straws this time. There is basically the same exact result with the two straws. There was still a vacuum being created and the air pressure so she would get the same amount of water. The last experiment, had some real excitement in it. This time, our fellow classmate once again (thanks classmate) “tried” to drink water but with a straw in the cup and a straw outside of the cup. This time however, she could not drink the water. This was because the vacuum that was once created before, was filled with air and could not be a vacuum because the straw outside of the cup took in water and filled the water. As she tried to suck in water, the vacuum kept on being filled with air and all she would suck in was air. The seal that was once there for the vacuum was broken.

First picture was classmate drinking water with regular one straw.
Second picture was classmate “trying” to drink water with a straw in cup and straw out of cup.
Original picture and drawing by Tony Park (sorry for bad drawing)

Air pressure changes in an airplane and this causes our ears to pop when the plane ascends and descends.  As you ascend in an airplane and the air pressure decreases at fast rates, the air trapped in your inner ear will cause your eardrums to push outward.  This pushing of eardrum causes you discomfort and also causes the “pop” in your ears. As you go down in an airplane and descend, our ears also pop once again. This time, the exact opposite thing happens and the eardrum is pushed inwards. This is because the air pressure increases at a very fast rate but your ears are still adjusted to the lower air pressure.
This diagram shows what happens to one's ear as the air pressure changes as you go up or down an airplane
http://www.merckmanuals.com/media/home/figures/ENT_eustachian_tube.gif

Here is a really swell video showing an explanation of why our ears pop as we fly  

http://www.youtube.com/watch?v=SWg4qKzrUoo