Chilean Earthquake…Wednesday September 16, 2015

The west coast of the United States main land and Hawaii had tsunami alerts posted after the quake near Coquimbo, Chile Wednesday morning.  This quake was determined to be an 8.3 on the Richter Scale.  In an article from the (Tsunami Alarm System) web site it was stated that the quake’s energy had to be at least 7.0 on the Richter Scale.  From Australian Geographic in an article entitled (“Tsunamis: how they form”)  Professor Dale Dominey-Howes, co-director of the Australian Tsunami Research and Natural Hazards Research Centre at UNSW stated “ Broadly speaking earthquakes have to be a magnitude 6 or above to trigger a tsunami, and the closer to the sea floor an earthquake is the more likely it is to generate a tsunami.”   Professor also said that while regular ocean waves have a wavelength (distance from wave crest to wave crest) of 30 to 40 meters, tsunami wavelengths can be from 100 to 200 kilometers.  These waves could arrive on shore anywhere from ten minutes to nearly an hour apart.  In miles this is from 62 miles to 124 miles. (Fact Monster)

Now how is a tsunami formed?  On the ocean floor where fault lines form at plate boundaries you will have two types of boundaries.  A convergent boundary is when plates move toward each other.  The older and denser crust will be subducted (go under) the other plate where they meet.  This is called a subduction zone.  At the subduction zone the older denser plate will slowly bend the leading edge of the younger, less dense plate.  Crustal rock (rock in the crust of the Earth) has a property called elastic rebound.  Which means the crustal rock is like a stretched rubber band.  It wants to snap back to its original shape.  At the fault line after a very long period of time the friction between the two plates, grinding past each other, will no longer be able to stop the younger, less dense plate from rising back up to its original position.  This is when an earthquake happens.  As the sea floor rises up to its original position the water above the quake will be pushed up.  Remember unlike gases, liquids cannot be compressed.  As in the earthquake off Indonesia in 2004, the water rose by 10 meters/ 30 feet.  Next the raised dome of water creates waves that started moving away from each other in opposite directions.  In Lindsey Springer’s (springle@uwec.edu) article the tsunami wave in deep ocean moves at speeds from 450-650 mph and the wave is only 20 inches tall.  In other words boats would not even noticed it passed by.  As the wave approaches a coastline the leading edge slows down due to friction with the rising sea floor.  As the leading edge slows the rest of the wave behind still moving at speeds of 30 to 200 mph.  Thus the large waves are formed.  Lindsey also reported that the waves can be as high as 100 feet or more, and the wave from front to back could be from 5,000 to 10, 000 feet.  Imagine a wave 100 feet high and nearly two miles size from the front of the wave to the back of the wave.  This wave just does not wave up on the shore and recede quickly.  The tsunami wave will continue to push in land for miles taking everything with it.

http://observe.arc.nasa/exhibits/tsunami/tsun_physics.html

http://observe.arc.nasa/exhibits/tsunami/tsu_physics.html

            Other ways tsunamis can be formed are: volcanic eruptions, huge landslides into the ocean, and even meteor or asteroid impacts.  In 1883 the Krakatoa Volcano off the coast of Sumatra, Indonesia blew itself apart in a massive explosion that created a tsunami wave that was 120 feet tall when it struck the surrounding islands.  Over 33,000 people died. 

There is a volcanic mountain in Canary Islands off the west coast of Africa.  Scientists are stating that one day a massive chunk of rock, some 220 square miles, in an eruption of the Cumbre Vieja volcano on La Palma Island will crash into the Atlantic Ocean creating a tsunami wave that would be the biggest ever. (Steve Connor: The Independent-London)  In Connor’s article “Scientists Warn of Massive Tidal Wave from Canary Island Volcano”, he writes that the resulting wave could be as high as 169 feet as it crashes into eastern seaboard of America, Brazil, and inundate much of southern Britain.  (Rense.com/general13/tidal.htm)   (http://news.independent.co.uk/world/africa/story.jsp?)  

But other geologists are even saying that this 220 square mile chunk of the volcano will slide into the ocean as a result water erosion in the mountain and the force of gravity. 

There is also disagreement of whether or not a tsunami wave of such great size would even reach the east coast of the United States.  These scientists say that a tsunami created by a landslide from an exploding volcano would be short-lived with there being little or no waves that reach the east coast.  The tsunami wave created by the explosion of Krakatoa Volcano in 1883 was over 100 feet high but there were no reports of damage outside areas of Indonesia.  While the 2004 earthquake-created tsunami in Indonesia affected large areas as far away as Africa; killing nearly 300,000 people along the coastlines of nearby countries. 

So only time will tell who is correct.  But all do agree it will happen, but no one knows when.  Scientists are calling for better monitoring the volcano’s activity to warn of possible danger, and give countries enough time to get people out of the way of the tsunami.

Sources, Follow-up links:

Information about terms, causes, characteristics, occurrences, prevention and list of past tsunamis  (www.en.wikipedia.org)  

(www.ess.washington.edu)

(http://www.tsunami.org/index.html)

www.teachervision.fen.com

Behavior in case of a tsunami (http://gfz-potsdam.de/index-en.html

(www.tsunami-alarm-system.com/en/phenomenon-tsunami-formation.html)

(http://www.australiangeographic.com.au/blogs/on-this-day-in-history-boxing-day-tsunami)

Academic.evergreen.edu/g/grossmaz/springle

Rense.com/general13/tidal.htm

(http://news.independent.co.uk/world/africa/story.jsp)

(http://www.thisislondon.com)

Finding the Density of an regular shaped object.

The Density of an Object Method

            Density of an object is more important than you might think.  Have you ever seen how some people can float in a pool without even having to move a muscle while others have to move to stay afloat?  Have you been able to float in the ocean better than you can float in the pool?  This is all about density.  Why is it that most rocks sink in water while pumice rock floats very well in water?  How can a silver dollar coin float on liquid mercury?  Again, it is all about density.  Why does cold air sink and warm air move up?  Why does granite rock carry seismic waves better than sandstone?  Why will salt water remain at the bottom of a beaker below freshwater in the same beaker?  Why does cold water sink and warm water rise.  Guess what?  It is all density!

            In my years of teaching sixth grade science, students had a hard time of understanding density.  So they were introduced to it in my classes.  There are two ways to find density: for objects that you can measure with a metric ruler.  These were regularly shaped objects that have a length, width, and height; and the other was using a graduated cylinder and water as part of the process to find the density.

            Now density is described as the relationship of an object’s mass in grams to it volume in milliliter or cubic centimeters.  This above named mass and volume units would be larger for big objects.   Such as kilograms or liters.  Now rereading the definition of density, you may have a questioning look on your face.  I know my sixth graders did.  So we discussed it a lot.  In this case what we were trying to understand was this.  So if I have 1 cubic centimeter piece of something; that 1 cubic centimeter of that something would have a certain mass.  In other words…say you have an object that has a volume of 1 cubic centimeters and its mass is 2 grams. 

            Here is where the math comes in.  The equation for calculating density is: density is equal to the mass of the object divided by its volume.

D= mass divided by volume

D= M/V

So density is equal to 2 grams divided by 1 cubic centimeter

D= 2 grams/1 cubic centimeter

D= 2g/1 cm³

D= 2g/cm³  (2 grams per cubic centimeter)

Therefore each cubic centimeter of that object will have a mass of 2 grams.

The object’s density is 2 grams per cubic centimeter.

1.                   If an object has a mass of 10 grams and a volume of 5 cubic centimeter, what is its density?  Remember to divide the mass by the volume and the units in the answer are grams per cubic centimeter.

D= 10g divided by 5 cm³.  10 divided by 5 = 2   D= 2 g/cm³

2.                  If a rock has a mass 25 grams and a volume of 5 milliliters, what is its density?  Remember to divide the mass by the volume.  Your answer will have the units of grams per milliliter.

3.                  This object has a volume of 50 mL and a mass of 400 g.  What is its density?   Remember your units will g/mL.

Finding Volume of a block of wood

1.                  You will use a metric ruler that is correct for what you are going to measure.  In this case a 30 cm metric rulers works very well.

2.                  You will be measuring the block’s length (longest side), them width (next longest side), and finally the block’s height or thickness.

3.                  You will measure to the tenth of a centimeter also known as 0.1 centimeters.  Be sure to record what you  have written down what you measure on a data chart to a tenth of a centimeter.

4.                  First measure the length.  Refer to the picture below.

a.      This measurement is 14.8 cm

5.         Now measure the width of the block in centimeters.  

Refer to the picture below.

            a.         This measurement is 4.4 cm.

6.         Finally you will measure the height or thickness of the block.  

Refer to the picture below.

            a.         The measurement is 1.8 cm.

7.         Now you are ready to use the math formula of Volume is equal to the                   length times the width times the height.  It can be written this way:
           V=LxWxH.

            a.         First multiply 14.8 times 4.4

                                                               14.8

                                                              X4.4  

                                                                582

                                                            +582 

                                                              6512

            b.         Now multiply 6512 by 1.8.

                                                              6512

                                                              X1.8 

                                                            52096

                                                          +6512

                                                         117.216   cubic centimeters       

c.         But for a scientist this is not the final answer.  For scientific                                    accuracy the answer can only be as accurate as the measurements                          which in this case are only accurate to one decimal place or 0.1                              cm.

d.         Using your math skills in rounding, you will round the above answer                     to one decimal place or 0.1 cm.

                    i.          Looking at the answer: 117.216 the 6 digit is greater than 5                                   so the 1 to the left is rounded up to a 2.  But since the 2 is                                       less than 5 the .2 digit is not affected and stays a 2.

e.         Therefore the final answer for a scientist is 117.2 cm³   
            This answer tells other scientists that the measurements to find the
            volume of the block were only made to a tenth (0.10 of a centimeter.

8.         The next part is the measure the mass of the block of wood in grams 
            using a balance or digital weight device.  Again the mass is measured to a
            tenth (0.1) of a gram.  Hopefully you already have been trained to use
            that equipment.

            a.         The mass of the block is 58.8 grams.

9.         The formula for calculating density is:  Density is equal to the mass of the
            object divided by its volume.

            a.         D=M/V

10.       In this problem you will be dividing a larger number (divisor) into a
            smaller number (dividend).  This means you will have a zero point (0.)
            some number answer (quotient).

a.         In this math process you will divide 117.2 cm³ (divisor) into 58.8 g (dividend).  Remember your quotient will be less than 1.  Meaning you will start with a 0. then a number.

b.         When 58.8 g (dividend) is divided by 117.2 cm³ (divisor), your answer will be:

            0.5017064846 g/cm³

c.         This answer is not yet finalized.  Look at the number of decimal places your measurements were made to.  As you can see it was only 0.1.  This means your answer can only be accurate to a tenth or 0.

d.         So you round your answer to 0.5 g/cm³.

11.       Your final answer for the density of this block of wood is 0.5 g/cm³.

QUESTION:

If the density of distilled water is 1.0 g/ml, and 1 cm³ is equal to 1 mL; will this block of wood sink or float in distilled water?

The Stuff under Our Feet

           On you stand on solid ground the next time give some thought to what geologists theorize is happening under us.  Of course theories are based on a lot of collected information and data from years of research and experimentation.  With the earth's interior structure much of this information and data is called "second-hand" due to the fact that what they are stating has never been tested or seem directly.  So geologists use this information to formulate a theory about what is happening under our feet.  A theory is the best explanation for what is happen inside the Earth.

REMEMBER THIS IS THE STUFF THAT THEORIES ARE MADE OF.

NOT ALL GEOLOGISTS AGREE ON THE INFORMATION BELOW.

SOURCES OF INFORMATION MAY NOT BE IN TOTAL AGREEMENT.


(From EnchantedLearning.com)

The layers:

1.  Lithosphere

     a. Crust

          i. Continental crust

         ii. Oceanic crust

        iii. Mohorovicic Discontinuity...marks the lower boundary of the crust[i]

     b. Uppermost solid rock mantle is included in the lithosphere.

2.  Asthenosphere...upper mantle which is made up of weaker, plastics rocks

3.  Lower mantle

4.  D" layer (dee double prime)[ii]

5.  Outer core

6.  Inner core   

Layer Details

 1.  Lithosphere: 

      a.     It contains the continental crust.  This topmost layer contains the least dense                       rock.

          i. The thickness of this layer is from 35 km.[iii]   The continental crust will be                         thicker under mountain ranges sometimes as thick as 60 km.

         ii. This layer is made of lighter volcanic granitic rock with a density of 2.6                               gm/cm^3.[iv]

      b.     On the ocean floors is the oceanic crust.  This volcanic rock is basaltic and the                    thickness averages 5-10 km.  This layer has a higher density about 
               3 gm/cm³. [v]

      c.       This part of the lithosphere is the upper area of the upper mantle.  It is thought                    to be solid, rigid and somewhat cool.  Scientists also think the rock to be even                     denser.[vi]

      d.       The entire lithosphere has a thickness of 100 to 20 km.[vii]

---

[i] Geology.com

[ii] D’’ Layer Demystified

[iii] Lithosphere: World of Earth Science

[iv] Structure of the Earth-HyperPhysics

[v] Structure of the Earth-HyperPhysics

[vi] Lithosphere: World of Earth Science

[vii] Inside the Earth-Enchanted Learning

2.  Mohorovicic Discontinuty

     a.        The word discontinuity means that at this surface is where the speed of                           seismic waves from earthquakes change speed and sometimes direction.

     b.        This layer is found 32 km below the surface.[i]

---

[i] Geology.com

3.  Asthenosphere: Upper Mantle

     a.       This layer, which most areas are in solid rock form, also contains regions                        of hot bendable rock that can slowly flow.  The asthenosphere is found                          anywhere between 80 to 200 km beneath the surface and can extend up                          to 700 km down.   The asthenosphere thickness is affected by the                          b.         This means some regions of hard and rigid rock can become bendable 

                       and plastic-like as heat and pressure increases in that region 

                       of the asthenosphere.[ii]

     c.         Since some regions of the asthenosphere contain hot, slow flowing 

                        rock and this slowly flowing rock is called convection currents that 

                        circulate between the outer core and the lithosphere.

(from joidesresolution.org/node/1897)

     d.        The upper mantle has a thickness of about 410 km stretching 

                       from the crust down into the Earth's interior.

     e.        The transition zone is an area from 410 km to 660 km where there 

                       is no melting of rock, but instead the rocks undergo changes 

                       in their crystalline structure becoming a lot denser.[iii]  In other words                            the rock crystals are put under great heat and pressure and the crystals 

                       change into new and denser crystals.

4.  Lower Mantle:

     a.         The composition of the rock in this layer is in dispute among geologists.                         Some think the subducted slabs of lithosphere slowly sink into the lower                        mantle.  This means that they see the rock as hot and bendable.  Others                          feel that the lower mantle is not moving nor transferring heat through 

                       the process of convection.[iv]

     b.        The rock in this layer is hotter and denser than the layers above it.

     c.        This layer is at a depth of 650 to 2890 km.

           

5.  D’’ (Dee double prime)

     a.        Found a location from 2,700-2890 km below the earth’s surface and 

                      is often included in the lower mantle..[v]

     b.       This region can be very thin in some places, have large build-ups of 

                      iron and silicates, and even areas of large melts which maybe form a 

                      mantle plume. [vi]

6.  Outer core:

     a.           Located at 2890 to 5,150 km.

     b.          This layer is melted iron with other elements mixed in to make it 

                       less dense than the inner core.

     c.           Convection currents move about the outer core created the Earth’s                                  magnetic field.  NOTE: a, b, and c.[vii]

7.   Inner core:

      a.             At a depth of 5,150 to 6,370 km.

      b.            Thought to be solid iron and nickel.

---

[i] 10 Facts About Asthenosphere: Fact File

[ii] 10 Facts About Asthenosphere: Fact File

[iii] The third rock from the sun-restless earth

[iv] The third rock from the sun-restless earth

[v] Earth’s Interior & Plate Tectonics

[vi] The third rock from the sun-restless earth

[vii] Earth’s Interior and Plate Tectonics

Bibliography:

D'' Layer Demystified

news.sciencemag.org/2004/03/d-layer-demystified

Earth's Interior & Plate Tectonics by Rosanna L. Hamilton

www.if.ufrgs.br/ast/solar/earthint.htm

Inside the Earth-Enchanted Learning

www.enchantedlearning.com/subjects/astronomy/planets/earth/inside.html

Lithosphere-World of Earth Science

www.encyclopedia.com/topic/lithosphere.aspx

Mohorovicic Discontinuity-  The Moho

geology.com/articles/mohorovicic-discontinuity.shtml

Structure of the Earth-HyperPhysics

hyperphysics.phy-astr.gsu.edu/hbase/geophys/earthstruct.html

10 Facts About Asthenosphere-Fact File

factfile.org/10facts-about-asthenosphere

The third rock from the sun-restless earth

education.nationalgeographic.com/encyclopedia/media

Scary but True

Anyone in the United States is noticing the decline in students being taught cursive writing.  I found this artice at www.huffingtonpost.com/michael-j-killing-cursive-is-killin_b_4261572.html.  This gives an interesting insight to what we are doing to our children by not teaching good cursive writing.

How Do I convert Units in the Metric System?

I think the first rule for the metric system is not to compare it with our standard system.

How to change from one unit in the metric system  to another.

(from www.mathstuff.com)

Try converting 10.1 kilometers to meters.  

1.  The meter is placed at the UNIT position on this chart.  

2.  Next you will move the decimal point three places to the right.

3.  The 10.1 km changes to 10100.0 meters.

Try converting 23.56 grams to kilograms.

1.  The gram is placed at the UNIT position on this chart.

2.  Next you will move the decimal point three places to the left.

3.  The 23.56 grams changes to 0.02356 kilograms.

Try converting 45.0 milliliters to Liters.

1.  The milliliter is at the right hand side of the chart.

2.  Next you will move the decimal point three places to the left.

3.  The 45.0 milliliters changes to 0.045 Liters.

Try converting 4,236.567 kilometers to millimeters.

1.  The kilometer is found at the left hand end of the chart.

2.  Next you will move the decimals point six places to the right.

3.  The 4,236.567 kilometers changes to 4,236,567,000.0 millimeters.

Try these conversions using the chart above.

1,000 grams to kilograms

294.563 gram to milligrams

3456.78 milliliters to Liters

987.376 centimeters to meters

Metric Units:

Meters...length              Grams...mass             Liters...liquid volume

Cubic centimeters...volume 

Metric Abbreviation: 

Kilometer (km)  Meter (m)   Centimeter (cm)     Millimeter (mm) 

Kilogram (kg)    Gram (g)     Milligram  (gm

Kiloliter (kl)      Liter (l)        Milliliter (ml)     

Area= Length times Width= some unit squared.  Ex: cm2, m2

Volume= Length times Width times Height (thickness)= V=LxWxH= some unit cubed.  Ex: cm3, m3.     

How to find volume

There are several ways to calculate the volume of liquids and solids; even irregularly shaped objects.

To find the volume of a sharp edged block of wood follow this process.

1.  Here is the math equation:  Volume of the object is equal to its length
     multiplied by its width then multiplied by its height.  V=L X W X H

2.  Measure the object's length, width and height.  You will measure in
     centimeters up to one decimal accuracy.  Example:  10.4 cm

3.  You measure the length to be 10.4 cm, width 8.3, and height 4.2.

4.  Next you will multiple the length and width.   Then multiply that answer 
     by the height.
          a.  For scientific accuracy your answer cannot have anymore decimal
               places than decimal accuracy of the measurements.
          b.  Note the measurements are only measured to one decimal place...tenth
               of a centimeter.
          c.  This means to a scientist that answer can only be to the tenth of a cubic
               centimeter.
          d.  If the block had been measured to a hundredth of a centimeter, then the                answer would be to the hundredth of a cubic centimeter.
          e.  So calculate the volume of an object will always be cubic(some unit).
          f.  Now how do you place the decimal point in the answer below?
              i.     Just count the number of decimal places in the measurements.
              ii.   In the above measurements, there are three measurements with one
                    decimal place accuracy.
              iii.  So count the number spaces from the right to the left then place the
                    decimal point in your answer.

10.4 cm

X8.3 cm

312     

+832           

8632      

X 4.2      

17264       

+36528             

                                    362.544 cm3   (cubic centimeters)

Practice Problems

1.  Find the volume in cubic centimeters of this block of metal that has a length

     of 8.4 cm, a width of 6.6 cm, and a height of 4.2 cm.?

2.  What is the volume of a piece of wood that is 11.2 cm long, 8.5 cm wide, and

     4.7 cm thick (height measurement)?

3.  A square piece of wood has a length, width, and height of 8.21 cm.  What is 

     its volume?

Volume of a Liquid

1.  To find the volume of a liquid you would use a graduated cylinder and 

             pour the liquid in the cylinder.

2.  You look at the liquid in the cylinder to see how much liquid in milliliters.

3.  To find the correct volume look at the cylinder eye-level.
4.  You will notice there is a curved waterline.
     a.  One of my students once said it looks like a contact lens upside down on               the top of the liquid.
5.  At the bottom of the curved line is where you  look to find the correct volume      in milliliters.  This curved line is called the meniscus. 

(from quantum.esu.edu)

(from www.thetechieteacher.net)

         

Volume of an irregularly shaped object

1.   First pour water into the cylinder to a certain volume...30 mL.
2.  Then carefully lower the object into the cylinder so as not to splash out any           water.
3.   Place the cylinder on a flat surface.
4.  Look at the water level at eye level and record the new volume level in
     milliliters.

5.  To find the volume of the object you will subtract the being volume before the      object was put in the cylinder from the volume of the water after the object

     was placed in the cylinder.

Example:   If you pour water into the graduated cylinder to the 25 mL line. Then add in the small rock...of it has to be smaller than the cylinder... and see what is the new level in the cylinder.  Say the new level is 42 mL.  Subtract the 25 mL from the 42 mL and you now know the volume of the small rock.  It is? Good answer!!!

     Of course the larger the object the larger the graduated cylinder.  If you have a really large object like a human body, this is what you would do.

1.  For large objects, you will use a container large enough to hold the object.
2. The container is filled with water until the water is just ready to flow out the
    container's spout.

3. Then have a way to measure the amount of water that flows out when the 

    object is carefully placed in the large water filled container.  

4. The amount of the water that flows out will show the volume of the object in
     milliliters or liters.

Decimals mean accuracy of measurement in science.

       This is where the scientific accuracy is applied.  This is not like in math where you do not round your answer.  But because the measurements were only accurate to one decimal place, your answer can only be accurate to one decimal place.  So the science answer is 362.5 cm3.

     Unlike math...in science measurements the number of decimal places indicates the accuracy of the measurements.  So if you have an answer of 3.4; it is not as accurate as an answer of 3.421.  In science even a zero behind the decimal point means accuracy where 4.000 is a lot much accurate than 4.0 or even 4.  If you had an answer of 4, this means your measurements were made as whole numbers.  For scientific accuracy your answer cannot have anymore decimal places than the number decimal places used in the measurements.  4 whole number, 4.1 measured to a tenth, 4.12 measured to a hundredth, 4.123 measured to a thousandth, and 4.1234 measured to a ten thousandth.

          Note the measurements on the block of wood were only measured to one decimal place...tenth of a centimeter.  This means to a scientist that the answer can only be to the tenth of a cubic centimeter.  If the block had been measured to a hundredth of a centimeter, then the answer would be to the hundredth of a cubic centimeter.  Did you know that 1 cubic centimeter is equal to 1 milliliter?

     Science Math Note

          Here is something else that is different in science.  When you read the answer from your measurements or the answer after your calculations is different in math and science. In math it would read fifty-three and 8 tenths cubic centimeters.  In science we read it as fifty-three point 8 cubic centimeters.  My experience as a science teacher is: when in science read the answer as a science answer and when in math read answer as a math answer.

          Case in point.   Where science is better for communication of data.  If you had a number that looks like this:  34.793 cm.  Would it be easier to read it as thirty-four and  seven hundred and ninety-three thousandth centimeters(math) or as thirty-four point seven nine three centimeters (science). In communicating data in science, it is important to keep it as easily understandable as possible.  How would you read this number....238.619034 kilometers according to how you would read it in math or reading it in science?  Which do you think would be easier to understand or even read?