Induction, Thurs. HMWK

Due Thursday:  READ p 392-399, including p.397! p. 399#1-7


Today in class: Induction!  
First we discussed the answer to the homework due today.  Not surprisingly, a great many people had no idea that the answer was actually verified for you in the reading on the next page (that was assigned - that means you aren't reading or aren't reading carefully at all!!!!)  
We started notes today by sketching how we were able to get the electroscope's leaves to move apart without giving it a net charge (keeping equal numbers of + and - ).  
For example, if a negatively charged rod was brought near the top of the electroscope, it pulls on (attracts) + charges and pushes (repels) - charges.  The + charges in a solid are representations of protons, so they can't move (they can move in a liquid/gas, or at least positively charged materials may move around).
The - charges in a solid are representing electrons.  These may move, as long as the solid is conductive enough.  Our electroscope was metal, so electrons move freely within it.  
Resulting from the repulsion of - charges, some electrons move down the electroscope into the foil leaves.  This separation of charge leaves the top of the electroscope (+) and the bottom of the electroscope (-).  Since the leaves have the same charge, they repel and the electroscope is said to be charged by induction.
Induction happens when charges within a conductor (usually we say a neutral conductor to keep things simple) move or separate within the conductor.  This happens without contact charging, or without gaining or losing any electrons.  
HOW???? can you motivate electrons to move within something?  The answer is invisible electric fields - 
Electric field: the space around a charge where electric force acts.  (the same force as magnetism, and will share some similarities with what we know about gravity)


We then got out lab materials: small sticks of PVC pipe, some rabbit fur, and Styrofoam balls with metallic (conductive!) paint on them.  Some Styrofoam balls were hanging from the ceiling by thin strings to allow for easy viewing of motions resulting from electric force.  People quickly discovered that a charged PVC rod attracted the balls, but only until they touched, then the ball quickly bounced away and repelled.  This appeared to be a parallel to yesterday's demonstration where neutral water was attracted to a charged balloon!  Everyone eagerly grabbed their notebooks and tried to make sense of this with a diagram depicting a charged rod and the conductive, neutral sphere.  Eventually we answered the question: the charged rod induces a charge (separates + and - regions) on the sphere, and the sphere is attracted to opposite charges and repelled from like charges.  
This still didn't answer the question, because it seemed that the charges were equal strength and these forces would cancel.  A few brave, bright individuals came up with the answer:  The attractive force between opposite charges was over a shorter distance than the repulsive charge!  Even when this difference in distance is small to our eyes, it's large relative to an atom, and we'll see tomorrow that electricity and magnetism, like gravity, are inverse - r squared relationships - double the distance (radius) between items, and the force changes by a factor of 2^2, or 4.  So yeah, distance between charges is a big deal.

Tomorrow we'll get a chance to look at the equation for electricity, you'll draw diagrams and answer questions about charging by contact and induction, and we'll learn a bit more about Electric Fields and how they're arranged/determined.  (plus go over the test - essay!)

Electroscopes - Charging by Contact, Thurs HMWK

Due Thursday:  READ p 392-399, including p.397! p. 399#1-7.  Two classes will have random quizzes over the reading as well, so please do read through - it will give you some good background for class discussions!

Today in class we warmed up with some algebra- exponent practice to help everyone with the homework problem due Tuesday, and then we got out electroscopes to experiment with charging by contact - see the 2nd part of the video below (it's a different type of electroscope than ours).  Tonight's question is how you could get the electroscope to move without touching it (without actually transferring electrons onto or off of it) - everyone saw this happen in class - moving a charged object near you could make the electroscope "dance" but when you moved away, the foil leaves fell back to a neutral position, which would not have happened if you had changed the balance of charge in the electroscope.  Finally, most classes got a chance to see the same phenomenon when holding a balloon near a stream of water - neutral water - so why did the water bend toward the balloon?  The answer is a big topic we'll discuss tomorrow and the first part of this video: Charging by Induction.

HMWK Tues! plus Atomic Structure/basis for electricity

HMWK Due Tuesday:  READ p. 579 (top paragraph), 583, and 584.  Work p. 583, #6 (at least to the best of your ability)

On Thursday we had some notes in class regarding the atom's components and layout.  

We discussed things you already knew (I was impressed overall!) and organized knowledge into a data table of sorts:

Name     Symbol    Location     Mass         Charge

Proton      p+          Nucleus      1a.m.u.         +

Neutron   n0           Nucleus       1a.m.u.        N/A

Electron   e-      electron cloud   almost none   -

Some notes:  The size of the negative charge on the electron is equal to the size of the positive charge on the proton; they are equal in size, just opposite.

a.m.u. stands for "atomic mass unit", which is just simpler to use to refer to tiny masses than a unit like grams or kilograms, which would be in units WAY less than billionths.

"positive" and "negative" are just arbitrary names; there's nothing inherently good or additive about protons; nothing bad or subtractive about electrons - they are just handy, universally accepted opposites - the names might as well be "ketchup" and "mustard".  

"electron cloud" refers to the space outside the nucleus, not too specific beyond that, according to most recent atomic theory.

If atoms do exchange any of these particles, it's almost always got to be the electron.  Why? 2 reasons:

1.  the electron is on the outside of the atom - WAAAAAY far away from the protons and neutrons in the center.  They're what actually can get bumped into.

2. The electron's mass (therefore its INERTIA) is WAAAY smaller than that of a proton or neutron.  Much easier to move around, if you recall anything from last semester.

We looked at an example of a neutral atom, a Carbon having 6 protons, 6 neutrons, and 6 electrons.  Since protons and electrons are equal, the atom is said to be electrically equal.  

Now what happens if this Carbon were to lose an electron?  only 5 electrons and 6 protons, so an overall positive charge remains.  That's right, loss of a particle from an atom makes it positive.  Somewhat counter intuitive, but that's what we're left with - blame the founding scholars of electricity who named things + and - inconveniently.  :)  Geez, Ben Franklin!  

Test tomorrow! Study!!! see Wed. post for links

Today in class we had a TGT review game for bonus points.  A few crafty individuals did notice that I already posted them online last Wednesday.  (you can still go to that post and get a copy for yourself).
Other review materials and ideas are on that post, plus any reading of your notes and chapter 12 since we've been back this year.
Bring a #2 pencil and a calculator tomorrow.

Study!! Exam Tuesday, Wednesday's links-review, Movie-Monday

Today classes finished notes and got answers corrected on the Earthquake Epicenters packet and the p.378 hmwk.  We discussed volcanoes quite a bit and I answered many interesting questions.
Next week:
Monday we'll have a review game, or you may work on independent study or ask me questions.

Monday after school: Supervolcano Movie for those of you who want to attend.  Popcorn and cookies privided, ok to bring soda or your own food too.  Several parents have expressed interest in rating info/details (it's a BBC movie that was shown on the discovery channel in the US a couple of times in 2005).  Get more details here at IMDb.  Check out the reviews to get the best idea of what it's about since there's not much on the main page.  It's rated 12 (see UK video classification system) since it does involve a scary subject, and there are deaths (millions) cited in the film.  Mild bad language is minimal, and not glamorized.  The only reasons I'm not showing it in class are:  Time (2 hours = 2.5 class periods) and Fiction:  it's not a documentary, although it's a pretty darn good docu-drama, not like most others.  (Dante's Peak, Volcano, Twister, Titanic, Pearl Harbor, etc)  As one critic put it, it's what isn't in this film that makes it good:
"No annoying child who refuses to obey his/her parents in a moment of dire emergency.
No cute dog to be dragged from the jaws of death.
No lean-jawed hero type performing super-human feats amid searing lava/magma/steam/boiling water.
No sweet young woman to grow progressively grubbier as she escapes impending disaster.
No tedious romance between the previous two characters.
No scenes of self-sacrifice as someone gets squashed under fallen debris - the squashed person gets out, and he lives!
No long winded,slow motion, pyrotechnic extravaganzas of major cities being blown up,crushed, swamped, engulfed, set on fire or otherwise obliterated."
Tuesday we'll have our exam - there will be a component that is multiple choice and a short answer / diagram / problem solving / essay portion depending on which test form you receive.

Wednesday I will display scores for the multiple choice exam and we'll follow up with one more video on volcanoes (the least focus on our test) that will be, as the others have been, very visual and interesting.

Thursday and Friday we'll start laying groundwork for out next unit: Electricity & Magnetism.  This won't be closely connected with our current studies, but there will be a good deal of Earth Science in learning about the earth's magnetic field and also later in astronomical implications...

Exam Tues. New due dates for Op Assign, Monday Movie

Exam Tuesday (chapter 12).  See yesterday's post.
Optional Assignment (see last Tuesday's post....) Part I now due next Tuesday, Part II due by Jan 31.
Movie: Supervolcano - now will be played next Monday after school.

Today:
Classes finished notes on plate tectonics, (evidence), and finished the documentary - "The Truth About Yellowstone" - showing what Yellowstone is (a hot spot volcano over continental crust, which has made multiple huge calderas in "super" eruptions in the past), and what would happen in a worst-case scenario of if Yellowstone erupted again as powerfully as it has several times in the past.  (really bad, but we can be prepared for events that aren't necessarily worst case)

Recommended review:

https://docs.google.com/document/d/10DpRh4aq6DqmsupqKuG01RR6wJDEMmUMWar4YdMCnrs/edit?hl=en_US

https://docs.google.com/document/d/1lUcguZJ7rrp8X6BX3G-I6dhxP3eER71PIQdj-xirDBk/edit?hl=en_US

https://docs.google.com/document/d/13tzimJ3seS1JxRotx8HjR5X3vAnRrlpoldI8-aYt5BM/edit?hl=en_US

https://docs.google.com/document/d/1QXolDojRSitPYuJvNcs6efHiL1MJcsNK7yLp6664Nho/edit?hl=en_US

Also p. 384#1-13, 16-22 and p. 884 # 128,131,134,135,137 are good review.
My teacher's edition with answers is available upon request to check your answers; our numbers will differ on some of the p.884 problems though if you use the 8km/s p waves and 4km/s s wave speeds we used in class.

HMWK due tomorrow... Facebook users, follow link!

Read p. 372-378, p. 378#2-7
This will provide background for our discussions and in-depth study of volcanoes this week. 
Next Exam will be 1 week from today, Tuesday, the 24th.  Content:  Earth's interior, Earthquakes & plate tectonics, and Volcanoes. 

Today in class:
Discussed any questions to tomorrow's homework.  (was assigned last Wednesday)
Honors Chemistry I students came to speak to classes and answer questions.
Most classes finished notes on Plate Tectonics & Evidence thereof.

Tomorrow:  Discuss homework answers, why volcanoes occur, and finish video - "the truth about Yellowstone" & discuss. 
Next MONDAY:  Video after school if you're interested:  Supervolcano  (a fictional, but based on mostly possible events, movie).  Free popcorn & cookies & fun.  2:30-4:30.

Optional Assign: New Madrid Turns 200!

Part I  (problems #1-8) Due No later than Tuesday, January 24
Part II may be completed with Part I or later, as late as Jan 31. https://docs.google.com/document/d/1sgWVnshZSLCfiheeiNWwrSurQIh1oGl3Hi7cPrMKhGI/edit?hl=en_US

Epicenter Location, Friday hmwk

Friday; Read p. 373-378, and p. 378 #2-7.  Our Exam will be next Friday.

Today classes turned in homework and had some questions answered, then we jumped into applying yesterday's notes on how to find distance from an epicenter to a seismic station based on looking at a seismograph:

By knowing approximate speeds of P & S waves (we used 8km/s and 4km/s), we came up with a basic equation to explain distance from an epicenter:
P-S arrival time delay * 8 km/s = distance in km from earthquake epicenter.

Today we used this knowledge to find distances from an earthquake to three different seismic stations, then drew circles around each station to show where the earthquake could have originated.  The first circle wasn't very specific, but when a second circle overlapped, two points could have possibly been the source of the earthquake.  A third station's data confirmed which of the two points was the location of the epicenter.
This is a process called triangulation.  It is the same technique used by GPS units; they must be within range of 3 satellites to determine the unit's distance from each, which pinpoints a location.


Tomorrow, classes will work to complete the assignment and we'll finish notes on plate tectonics.  If you finish early, I will ask some people to help their peers understand/complete the assignment - otherwise you may get started on your assignment for Friday; Read p. 373-378, and p. 378 #2-7.  Our Exam will be next Friday.

Epicenter Location using P-S delay, HMWK tonight

Homework tonight:  Read p. 370-372, p. 372#1-5.   On #5, change the wording from "mantle" to "mantle's thickness".  (thanks to Maura for pointing that out).
Our test will likely be next Friday, the 20th.  Topics will be:  Earth's interior, plate tectonics, earthquakes, and volcanoes.  You need to know vocabulary, understand concepts related to our understandings, be able to cite and explain evidence supporting our knowledge, and use math to solve related problems.
Today in class we worked a problem to start out:  An Earthquake is 150 km away.  Find:
1. time for P wave to arrive
2. time for S wave to arrive
3. P-S delay
4. Equation relating delay to P&S wave speeds & distance
For answers to 1&2, we used the basic "speed = distance / time" equation and some algebra to solve for time:
1. 18.75 s
2. 37.5 s
For 3, subtract the P time from the S time and get a familiar number:  18.75s.  The reason this comes out the same as the P time is due to the numbers we're assuming for P wave and S wave speed, which aren't exactly the exact values we would have in the Crust, but close enough that the math is easier and you hopefully get the concepts.
For #4, we worked with different ideas in different classes, but eventually came up with the simplest equation that works for our numbers:  distance to epicenter = P-S delay * 8 km/s

Finally, we looked at a sample seismograph and:
a. labeled P,S, surface waves
b. used P-S delay to find distance to epicenter from seismograph station
c. found time of earthquake origination.

Afterward we continued on with our plate tectonics notes, found here.

Tomorrow we'll work on more notes, answer the homework questions, and work more epicenter location practice before embarking on a large project to use real data to find real earthquakes.

H Chem? and HMWK for Tuesday.

HMWK for Tuesday:  Read p. 370-372, work p. 372#1-5.  This will be easier than your two previous assignments.  :)
Today in class:
Everyone received their "algebra review for chemistry" worksheet, graded.  Mrs. Greene came to visit and discuss answers/solutions to the worksheet, expectations for Honors Chemistry I, the Honors Science course sequence, and summer homework (packet handed out - you must sign up for an element to make a 3D model of an element.  You can't choose H or He, and you must sign up on the sheet in her classroom (rm. 213) by the 1st week of May.
After Mrs. Greene's visit, we had a competition for naming tectonic plates.  Individual class winners were:  Cheney (20), Thompson (23), Robinson/Sekarski (23), Wolk (17), and Vance/Goetz (8).
Classes had a few minutes to spare, and depending on where notes were, we either took notes, discussed the Earth's interior without notes, or discussed some general science news.
Have a great weekend!

PlateTectonics (HMWK tonight!)

HMWK tonight:  Read 362-369.  On p. 369, #1-7.  For #6 and #7, please change the numbers in your book. Use P waves @ 8km/s and S waves @ 4km/s.  Feel free to fix this in pen - will prevent future troubles for me!

FRIDAY:   Competition for bonus points:  Name the most tectonic plates out of your class.  There are 7 major plates, many small plates, and lots of microplates.  All are fair game.  You must memorize and then write from memory in the competition.

In class today:  Reviewed how waves provide the bulk of evidence for what we know about the Earth's interior (from yesterday).
Watched a couple of video clips on subduction zones, convergence, and earthquakes as well as divergent plate boundaries forming new oceanic plate at a mid ocean ridge.
Took notes and discussed plate tectonics.
Get a copy of notes (with images) here.

Several classes also got answers to last night's homework.  Will finish tomorrow if not.

Tomorrow we'll continue notes and discuss answers to homework from today and tomorrow.

Friday Mrs. Greene (Honors Chem I teacher) will come give you your algebra quizzes back and speak to you regarding Honors Chemistry to help you decide if you are interested in the challenge.

Afterward we'll have our plate - naming competition and work some problems involving wave speed and P-S lag time to prepare for next week's work when we locate earthquake epicenters!

Waves: How we know what's inside the Earth

Homework tonight:  Read p. 354-361; p. 361#1-9.
Also, due Thursday:  Read p. 362-369; p. 369#1-7.
On the p. 369 assignment, change two values in problems #6 and 7, and make them IN PEN in your textbook please:
#6 make the p - wave speed 8 km/s
#7 make the s - wave speed 4 km/s

Today in class:  sharing of ways to show that the Earth is round.  Very creative solutions were shared by many, bringing up lots of engaging discussion.
After the "Round vs. Flat Earth" evidence, we:
--> took notes on waves:  Speed, Refraction (bending), and types, as well as the implications of Earthquake waves in giving us evidence of the Earth's interior composition and nature.
A basic outline of the notes follows:
Wave Speed:  Waves move at different speeds based on the medium (material the wave is moving through).
If a wave encounters a boundary between one medium and another, it may change speed (+ or -).
If this boundary is encountered at a right angle, the wave is largely unaffected in direction.
If the boundary is encountered at an angle other than 90 degrees, the wave will be bent, or refracted:
Good diagrams here:  http://www.ux1.eiu.edu/~cfadd/3050/Ch16R&R/RefR.html

This occurs with all waves: light, radio, sound, seismic, water, etc.  How is this at all connected to Earth Science?  The image below illustrates seismic body waves moving through the Earth away from an earthquake epicenter.  If the Earth's interior was uniform, waves would travel in straight lines.  They don't; they curve back toward the surface, and in some places curve multiple times.  This tells us that the Earth's interior has different densities and temperatures...  As for the Shadow Zones at the bottom, read on.

There are two main types of waves; longitudinal (forward and back) and transverse (side to side):

In a longitudinal wave, the medium vibrates in the same direction as the wave moves (parallel).  In a transverse wave, the medium vibrates perpendicular to the wave's direction of motion.
In Seismic waves, these waves both exist.  Longitudinal waves move fastest through the Earth and are called Primary waves, or P waves, because they arrive at distant locations first.  Transverse waves move a little slower and are called Secondary waves (S waves).  Here's the really weird thing:  S waves don't travel through the center part of the Earth at all; they are absorbed.  The best explanation for this to date is that S waves don't travel through liquids, and this region, now dubbed the "outer core" is probably liquid.

Happy New Year!

Homework: (3) Due tomorrow:  describe a way to show that the Earth is round/spherical, not flat.  This may be using any techniques as long as it's possible - bonus points will be awarded to those with unique/simple explanations of how this could be done, especially low-tech ways that the Greeks might have argued about (most scientists have long believed the world to be a sphere, long before Europeans started crossing the Atlantic).
Due Wednesday:  Read p. 354-361, p. 361#1-9
Due Thursday:  Read p. 362-369; p. 369#1-7

Today we discussed new policies for this school year and reviewed Earth Science topics learned in the past:
New policies:
->more strict control by Mr. F. over materials in class following thefts last semester
->Official Lab notebook writeups optional - if you do this, you're making your grade mostly governed by tests!
->Pop quizzes will appear based on the reading assignments.  Not for huge amounts of points, but the reading provides an important foundation (review, basic concepts, vocabulary) for the material I teach in class.  Many people did not read last semester, so I am doing this to reinforce the importance of reading and to provide evidence to parents worried about bad grades.
->Late Homework:  Late work may be turned in 1 day after the submission deadline for 50% credit.  Since the homework is often discussed / reviewed the day of submission or the day after, there's really no reason anyone can't get an assignment finished by this 1 day past.... except laziness and refusal to keep up with work.  You can still turn in homework from this week in May... it just won't be counted for credit toward your grade.
Earth Science topics:
Earth's composition / place in the solar system / Energy in the Earth, Plate Tectonics, weather, climate, seasons, the Moon, and many other ideas were thrown out by all.
Tomorrow we'll start to dissect the evidence that the Earth has layers with different qualities - since nobody's ever dug a hole deep enough - how do we know?