TODAY IS 15 SEPTEMBER 2007 -- Transform faults

Its not your fault; its not my fault! Transform faults are part of our planet's geology. We need to understand them for our own survival, as they are the source of innumerable, destructive earthquakes. Transform faults are long and relatively continuous where they cut across continents, but tend to appear as short discontinuous segments offsetting sections of spreading ridges on the ocean floor. The transform fault is simply a fault connecting two other kinds of active plate boundaries, but that is a deceptively simple definition. Follow the link about paper models of transform faults. Do that now, please, and print out the model. (The web address is http://web.mala.bc.ca/earle/transform-model/ if you have trouble with the link.) Directions for printing the model are contained in that website. Then, return here:

Welcome back. Now, assemble your model from the directions given. Your model is very similar to small portions of the Mid-Atlantic Ridge between South America and Africa.

Begin with the model in its closed position. The two points marked A and B should be juxtaposed (what does "juxtaposed" mean?), and the gaps at the two spreading ridges should be closed tightly. Now open the model. Note how new plate material is "created" at each spreading ridge and an equal area is added to each of plate A (the shaded plate) and plate B (unshaded). Also, notice that after spreading has occurred, the two ridges are no farther apart than before spreading. Verify this by measuring distance DD' with the model closed and distance EE' with the model open.

The model illustrates the fact that the shape of an oceanic ridge does not change with time.

Now turn your attention to the fault itself. With the model closed, imagine yourself standing on point A, looking across the fault to the juxtaposed point A'. Slowly open the model, watching how point A' moves as seen from point A. If you are standing at point A, you will see point A' move to your right.

Turn the model around and repeat the process. If you are standing at point A', you will see point A moving to your right. Because of this independence of where you happen to stand, this particular transform fault is said to display right-lateral motion. That is, the motion is side-to-side and the other side of the fault always moves to your right.

Transform faults may also be left-lateral, if the ridges are offset in the opposite sense. To see this, turn the model page over to the other side and trace the positions of points A and A' on the reverse side of the paper. Holding the closed model so that you are looking at its reverse side, open it and note the motions of points A and A'. If you are standing at point A, you will see point A' move to your left.

The combination of ridge segments and transform faults forms a rectilinear zigzag pattern for oceanic plate boundaries that may be seen clearly in Figure 3-3 (on the website). It is still not clear just how this zigzag pattern is formed initially, but because the pattern does not generally change shape with time, it must have come into existence at about the same time as the ridges themselves. The process by which this happens is still not fully understood.

Where transform faults cut across continents, however, they tend to be long and relatively continuous, with few, if any, spreading segments. The best known and most studied example of a continental transform fault is California's San Andreas.

Now look at the satellite photo below:

It shows land and ocean floor to the west of the San Andreas Fault. This area is part of the Pacific Plate and is moving to the northwest, parallel to the fault. To the east of the fault is the North American Plate. Where the San Andreas Fault crosses the North American continent it is long and unbroken, but where it goes out to sea, it is cut into shorter segments separated by spreading ridges. Some of the ridge segments themselves are quite short, as in the Gulf of California.

Note that the ridge and fault geometry is similar to that of your paper model, for which right-lateral motion is expected along the fault. This is in fact what is observed along the length of the San Andreas. It is a classic transform fault, where the Pacific Plate is sliding past the North American Plate, carrying Los Angeles and Baja California along with it.

Along the fault, the rocky edges of the plates grind against one another. In a few places, the slippage occurs smoothly. Here, any structure such as a fence or road that crosses the fault is offset at a rate of up to six centimeters (2-1/2 inches) per year. But in other places, the fault is jammed and does not move steadily. As the plates continue their inexorable motion, the forces exerted on the pinned fault build up with each passing year. Finally the rock can stand no more and it breaks, unleashing the pent-up energy as strong vibrations of the ground: an earthquake.

Today is 27 September 2007 - Analyzing soil for total organic content

After drying the soil, we will want to determine how much of it is due to organic matter. We can find this out by combustion analysis:

1. Purpose: to determine the amount of organic matter in the soil.

2. Materials: well mixed soil sample (from sampling ring) -- about 50 grams, hot plate, balance, evaporating dish (watch glass)

3. Procedure: Scoop out or scrape out about 200 grams of soil. Mix it well. Then take about 50 grams of this portion and weigh it accurately. Put it on the hot plate set at mid heat -- not HOT -- and note its location on the hot plate. There is room for about 9 dishes or watch glasses on the hot plate. That is why I said to note its location. Weigh it periodically. When the sample is at constant weight, it is dry. Weigh it again and record this weight. Then transfer all or a weighed portion to a crucible. It is important to know exactly how much you have placed in the crucible! Then, heat it with a bunsen burner until all organic materials have burned off. You can tell when combustion is complete because soot which deposits on the crucible in the early stage of burning will be oxidized and gone. If possible, do the combustion in the fume hood. Let it cool and reweigh. If we have a desiccator in which to cool the sample, use it.

4. Data: record the weights at each step.

The difference between the initial dry weight and the final weight is the mass of organic material which was present.

Today is 27 September 2007 -- Solar Cell Experiment

Have you ever wondered how a solar cell -- or photovoltaic cell, as it is properly named -- is made and how they operate? You have an opportunity to make one in this lab assignment. First, you should read information on solar cells. There is a good article about them on Wikipedia. Follow the link here to go to "Solar Cells." Then, follow this link to the UCLA Nanoscience page on about solar cells. Please study these sites before you come to class so you will know how the solar cell works.

After you complete the experiment, please write your report using the format that you have been taught. Also answer the "Discussion Questions" on the Nanoscience website.

Today is 28 September 2007 – We are studying Dynamic Earth Processes

Dynamic Earth Processes is a course of study identified by California as Standard 3.

“Earth sciences use concepts, principles, and theories from the physical sciences and mathematics and often draw on facts and information from the biological sciences. To understand Earth’s magnetic field and magnetic patterns of the sea floor, students will need to recall, or in some cases learn, the basics of magnetism. To understand circulation in the atmosphere, hydrosphere, and lithosphere, students should know about convection, density and buoyancy, and the Coriolis effect. Earthquake epicenters are located by using geometry. To understand the formation of igneous and sedimentary minerals, students must master concepts related to crystallization and solution chemistry. “

“Because students in grades nine through twelve may take earth science before they study chemistry or physics, some background information from the physical sciences needs to be introduced in sufficient detail. From standards presented earlier, students should know about plate tectonics as a driving force that shapes Earth’s surface. They should know that evidence supporting plate tectonics includes the shape of the continents, the global distribution of fossils and rock types, and the location of earthquakes and volcanoes. They should also understand that plates float on a hot, though mostly solid, slowly convecting mantle. They should be familiar with basic characteristics of volcanoes and earthquakes and the resulting changes in features of Earth’s surface from volcanic and earthquake activity.”

3. Plate tectonics operating over geologic time has changed the patterns of land, sea, and mountains on Earth’s surface. As the basis for understanding this concept:

a. Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence of plate tectonics.

Much of the evidence for continental drift came from the seafloor rather than from the continents themselves. The longest topographic feature in the world is the midoceanic ridge system—a chain of volcanoes and rift valleys about 40,000 miles long that rings the planet like the seams of a giant baseball. A portion of this system is the Mid-Atlantic Ridge, which runs parallel to the coasts of Europe and Africa and of North and South America and is located halfway between them. The ridge system is made from the youngest rock on the ocean floor, and the floor gets progressively older, symmetrically, on both sides of the ridge. No portion of the ocean floor is more than about 200 million years old. Sediment is thin on and near the ridge. Sediment found away from the ridge thickens and contains progressively older fossils, a phenomenon that also occurs symmetrically.

Mapping the magnetic field anywhere across the ridge system produces a striking pattern of high and low fields in almost perfect symmetrical stripes. A brilliant piece of scientific detective work inferred that these “zebra stripes” arose because lava had erupted and cooled, locking into the rocks a residual magnetic field whose direction matched that of Earth’s field when cooling took place. The magnetic field near the rocks is the sum of the residual field and Earth’s present-day field. Near the lavas that cooled during times of normal polarity, the residual field points along Earth’s field; therefore, the total field is high. Near the lavas that cooled during times of reversed polarity, the residual field points counter to Earth’s field; therefore, the total field is low.

The “stripes” provide strong support for the idea of seafloor spreading because the lava in these stripes can be dated independently and because regions of reversed polarity correspond with times of known geomagnetic field reversals. This theory states that new seafloor is created by volcanic eruptions at the midoceanic ridge and that this erupted material continuously spreads out convectively and opens and creates the ocean basin. At some continental margins deep ocean trenches mark the places where the oldest ocean floor sinks back into the mantle to complete the convective cycle. Continental drift and seafloor spreading form the modern theory of plate tectonics.

3. b. Students know the principal structures that form at the three different kinds of plate boundaries.

There are three different types of plate boundaries, classified according to their relative motions: divergent boundaries; convergent boundaries; and transform, or parallel slip, boundaries. Divergent boundaries occur where plates are spreading apart. Young divergence is characterized by thin or thinning crust and rift valleys; if divergence goes on long enough, midocean ridges eventually develop, such as the Mid-Atlantic Ridge and the East Pacific Rise.

Convergent boundaries occur where plates are moving toward each other. At a convergent boundary, material that is dense enough, such as oceanic crust, may sink back into the mantle and produce a deep ocean trench. This process is known as subduction.

Transform boundaries occur where two plates, or fractured portions of a plate, attempt to slide by each other. These boundaries are known as “faults” and are the source of much earthquake activity.

Today is 24 October 2007 -- How does a transistor work?

We will shortly be studying how the transistor works. Please go to the following web site and study the article on the history of this remarkable device. You can also jump to the transistor article by the hyperlink here. Develop five questions about the transistor based on the history article. In class, we will exchange questions with each other and answer them. Plan on two days from the assignment date for the class work.

Today is 28 October 2007 -- Here is how we start analyzing soil

The weight of an empty container is the TARE WEIGHT. The weight of the container WITH a sample is the GROSS WEIGHT. By subtracting the tare weight from the gross weight, you have the weight of the sample itself. This is the NET WEIGHT. When you begin an experiment, you have a STARTING or INITIAL WEIGHT. At the end of the experiment, you have a FINAL WEIGHT. When you express a fraction gained or lost in terms of the whole sample, you calculate a PERCENTAGE. Please answer the following questions:

"The tare weight of a watch glass is 3.025 grams. The gross weight (wet) of a soil sample is 9.034 grams. After drying the gross weight (dry) is 7.084 grams."

A. What is the weight of the water in the sample?

(All you have to do is subtract the dry gross weight from the wet gross weight. You don't have to account for the weight of the watch glass since it has not changed in weight.)

B. What is the dry weight of the soil in the sample?

(Subtract the tare weight from the dry gross weight.)

C. What is the percentage water in the sample?

(You want to know how much water was in the dry soil, as a percentage. Divide the amount of water by the amount of soil and multiply by 100.)

Today is 29 October 2007 -- We model atomic bonding with "magnetic floatees!"

In class we used mini magnets mounted on foam floats to model how atoms self-arrange into a configuration where they all have minimum energy. To prepare for this activity, we used pennies in various arrangements to demonstrate packing and studied the High School Nanoscience Program Self Assembly website. You were shown how the self-arrangement occurs. Use the hyperlink Self Assembly to go to the site. Read and study it all, especially the section on the floating magnets. Answer the 4 study questions on that website. Then, write a lab report on how the magnet self-assembly demonstration relates to atomic bonding and self-assembly of molecules from atoms. Use the website as the main reference. You should check out other references on-line, in the library or in your text.

Today is 14 November 2007 -- Students identified existing energy sources

Students were requested to come up with a list of ten energy sources that humans on Planet Earth use, or have been using over our history. We wrote the following list on the board:

Period 1

1. Wood

2. Solar

3. Wind

4. Gas

5. Coal

6. Hydro

7. Petroleum

8. Hydroelectric

9. Nuclear (fission reactors)

10. Electricity

Period 2

1. Manpower

2. Wood

3. Wind

4. Water

5. Coal

6. Petroleum

7. Gas

8. Geothermal

9. Nuclear (fission reactors)

10. Solar

Now, for your assignment:

1. Is this list complete? What other energy sources can you think of? Although the "ultimate" source of energy is our sun, you may also list conversion processes such as thermionic, for example. Please identify another five sources.

2. Once you have a list of 15 sources, place them in historical order and write dates of first use, if possible. For example, human manpower is likely the oldest source of energy, having been in use since there were people in a real society, perhaps 50,000 years ago.

3. Select one energy source. Research it at the library or through the Internet. Write a report about the energy source of not less than four typed pages (at least 1,000 words). Make sure you include at least the following four items:

a. Discovery -- Who discovered it? When was it discovered? What prompted the discovery?

b. Use -- How is the source mainly used? Are there other ways in which it can be used? What are they?

c. Pollution impact -- Is the source renewable? How? What byproducts result? Can they be used? How? Is the energy source hazardous to plant or animal life? What about the byproducts?

d. Cost -- How expensive is the source? What does it cost to produce per Watt (joule per second) of power?

Remember, these four items are the minimum. You should write about other aspects of the energy source, as well.

4. Select one of the inventors, discoverers or "notable individuals" associated with the energy source and provide a brief biography of that person. For example, who was Edwin Drake? For what is he remembered?

This assignment is to be completed in stages. You will have two days from date of assignment to complete parts 1 and 2. Part 3 is due 5 days later. Part 4 is due 2 days after that. This means that if the assignment is given on a Monday, the list of energy sources in historical order is due that Wednesday. The report on the energy source is due the following week Wednesday and the report on the notable person is due that Friday.

The unit assessment is planned for the same day Part 4 is handed in. Expect an essay question (3 paragraph), a design (drawing, chart, etc.) and an "evaluation" question (cost-to-energy ratio, life of resource, cost to society, etc.).

Today is 6 February 2008 -- Please complete the following "Basic Science Skills" assessment.

Download the assessment or copy to a word processor. You may turn in your work on-line or in class.

1. What is 5/8 of 16/30?

2. Divide 27/32 by 3/8.

3. The concentration of a chemical in a mixture is 0.023%. How much of the chemical is in 78 grams?

4. 3/8 of a pound of iron is added to 2/3 of a pound of carbon. What is the total weight?

5. 3/26 of an ounce of magnesium oxide is taken from 29/13 ounces of it. How much is left?

6. How many feet in a yard?

7. How many inches in a yard?

8. How many centimeters in an inch?

9. How many centimeters in a yard?

10. 200 milligrams of a substance is added to 2.79 grams of the same substance. What percentage has been added?

11. A mixture is analyzed. It contains 4.5 grams of “A,” 17.06 grams of “B,” 0.06 grams of “C” and the balance is “D.” The overall weight is 30.19 grams. How much “D” is present? What is the percentage each of A, B, C and D in the mixture?

12. Express 0.0011 in scientific notation.

13. What is “standard format?” Give an example.

14. Express 3,259,609 in scientific notation.

15. How many significant figures in each of the following (NOTE: Not multiple choice!):

a. 3.104?

b. 1.0400?

c. 4000?

d. 0.0023

e. 1.9 x 10-3

16. The formula for a certain chemical compound is HxSyOz where "x, y and z" are subscripts that tell how many of a particular atom is present. For example, H2O -- water contains two atoms of hydrogen and one atom of oxygen for a total of three atoms in the molecule. Now, for the problem, if z = 4, x = 1/2 z and y = 1/2 x, how many atoms are present?

17. Carbon-14 is a radioactive isotope of carbon that decays to nitrogen at a predictable rate. The decay rate is used as a "clock" to determine the date of archelogical specimens. The "half-life" is the time it takes for one half of the radioactive carbon in a sample to decay. The half life for carbon-14 is 5730 years. In other words, if you have 10 grams of carbon-14 to begin with, then after one half life, you have 5 grams left. (Make sure you understand the question. Explain to yourself what "half-life" means. )

a. How many half lives will have passed if the sample has 2.5 grams of carbon-14 left?

b. How many years will have passed in two half-lives for carbon-14?

18. The atomic weight of methane gas (CH4) is 16. The atomic weight of air is about 29. This means that methane gas is less dense than air so it will rise. We can demonstrate this by blowing a soap bubble with gas. As it rises, we can touch a flame to the bubble and watch it ignite. It's really fun to watch. But here is my question: if the bubble is 4 inches in diameter, how much gas is in it? (In other words, what is the volume of a sphere whose diameter is 4 inches? The formula is V = (4/3) x Pi (the value is 3.14, if you have forgotten) x radius cubed.

19. In biology and chemistry we often use equations of the form A = B divided by C. (A=B/C). If you know any two of these variables, you can solve for the third. For example, the volume (V) of a solid is 5.75 cubic inches and its mass (m) is 11.50 lbs. What is the density? (D = m / V)

20. This is the last question and it contains a trick. Think carefully before you answer.

a. What is the order of the numbers 1, 3, 5, 7, 9 ?

b. What is the order of the numbers 2, 4, 8, 16, 32, 64 ?

c. What is the order of the numbers eight, five, four, nine, one, seven, six, three, two, zero?

Today is 8 March 2008 -- Why is carbon able to enter into chemical reactions with so many other elements? And other questions.

Carbon has four electrons in its outer shell.  It needs to gain four to complete the shell, or to lose four so the underlying shell is seen as complete.  The energy to remove the four electrons is enormous so that doesn't happen (on this planet, normally, anyhow).  Gaining electrons would give it a high negative charge (four electrons, remember) and the charge imbalance between the four positive protons and four more electrons results in a very unstable ion.  So THAT doesn't happen.  Instead, the carbon shares electrons covalently with other atoms.  If it is in a salt like calcium carbonate, CaCO3, it is still covalently bound to the oxygen.    Further, since there are four bonds to be formed, the number of combinations are large.  Carbon can form single, double and triple bonds.  When it bonds to other carbon atoms, it forms a crystal or lattice as in diamond or Buckyballs.

2.  Why is water a liquid under normal atmospheric conditions?

Because although the hydrogen atoms in a molecule of water are covalently bound to an oxygen atom, they are not completely neutral in the sense that they are able to be attracted to the oxygen of an adjacent water molecule.  This "hydrogen bonding" is strong enough to keep the molecules from drifting apart under normal conditions.  In the atmosphere, when the air pressure is low, the molecules have enough energy to break free and form water vapor, or if heated, they gain enough energy to overcome the strength of the hydrogen bonds.  If our plant had a lower atmospheric pressure, or was hotter, there would be more water in the vapor phase and less in the liquid.

3.  Write and balance the decomposition of calcium carbonate:

This was discussed over and over in class.  I'm really disappointed that more of you did not write the correct answer.  When calcium carbonate is heated, it forms carbon dioxide and calcium oxide.  

CaCO3 --> CaO + CO2 .

4.  Write and balance the following reaction:  Complete oxidation of sugar (C6H12O6) in the body to produce CO2 and H2O.  Again, we went over this in class.

C6H12O6 + 6O2 --> 6CO2 + 6H2O

5.  Show the Lewis dot diagram for CaCl2

You know that this means one calcium and two chlorine.  You should know that chlorine has 7 electrons in its outer orbital and wants to gain one.  You also should know that calcium has two electrons in its outer orbital and can lose them in forming a bond.  Draw the dot diagram with chlorine on either side of the calcium like this:  Cl : Ca : Cl   Then, add two dots over each Cl, two under them and two between each of the atoms.  Now, check:  There are 16 electrons in all, seven from each of two chlorine atoms and two from the one calcium atom.  That adds up to 16 electrons.  Two between the Cl and the Ca (on each side) uses 4, leaving 12.  Since we need the same number of electrons for each of two Cl, divide 12 electrons by 2 atoms and get 6 electrons for each Cl.  Arrange the dots around the Cl.  Then, stand back and admire your artwook.  

Today is 20 April 2008 -- Ecology Study Plan

Your next assessment is in about four or five weeks.  It will cover ecology and evolution.  I want you to have the opportunity to study for this assessment so I am going to defer the study of genetics until after the assessment.  Taking the topics out of the original order in which they were in will not harm your study.  Genetics and heredity are certainly factors in ecology and evolution, but we do not need to study inheritance to understand them.  (See standard 7, below, for example.)  For your convenience I have listed the standards for ecology.  Please make sure you write the standards in your notebooks:

Ecology

 Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept:

1.  Students know biodiversity is the sum total of different kinds of organisms and is affected by alterations of habitats.

2.  Students know how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, or changes in population size.

3.  Students know how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration, and death.

4.  Students know how water, carbon, and nitrogen cycle between abiotic resources and organic matter in the ecosystem and how oxygen cycles through photosynthesis and respiration.

5.  Students know a vital part of an ecosystem is the stability of its producers and decomposers.

6.  Students know at each link in a food web some energy is stored in newly made structures but much energy is dissipated into the environment as heat. This dissipation may be represented in an energy pyramid.

7.  * Students know how to distinguish between the accommodation of an individual organism to its environment and the gradual adaptation of a lineage of organisms through genetic change.

Here is a schedule of how we can proceed with our study:

Monday, 21 April --

1.  (Copy standards during roll-taking.)

2.  Watch the power point presentation

3.  Break into Groups

4.  Follow the assignment on power point

5.  complete the homework assignment tonight.

Tuesday, 22 April

1.  Meet in the Quad

2.  Idenfity and count organisms in different areas of the school

Wednesday, 23 April

1.  Invasive plant video clip

2.  Causes of fluctuations in population sizes

3.  Analysis of counting

Thursday, 24 April

1.  Energy flows in ecosystems -- Sect. 13.3 in text

2.  Food web, food chain

Friday, 25 April

1.  Quiz

2.  Element recycling; water cycle

Today is 17 July 2008 -- Periodic Table and Air Pressure lessons

Remember, period 1.  If you are going to claim extra credit for spelling names with the periodic table symbols, your images have to be emailed to me or transferred to my computer by Friday.  Send them to abinc@aol.com.  Remember also your homework and notebooks are due on Friday.  Do not procrastinate!

Period 2 students, remember that your barometers are due on Friday for me to inspect.  That means completely assembled with card pointer and calculations done to show what a change in pressure would read.  Tomorrow -- Thursday -- we either fly a hot air balloon or study how to find absolute zero. 

Yeah, yeah -- I know.  Buzz Lightyear would say, "To absolute zero -- and beyond!"

About your Friday quiz:  Period 1 will be heavy on the Periodic table and trends.  I strongly advise you to answer the questions for HOLT Ch. 4 (Periodic table) in your workbooks.  Period 2 will be problem solving for gas laws and molarity.  Expect something on partial pressure and Graham's law of diffusion.  YOU WILL NEED YOUR SLIDERULES, SO GET COMFORTABLE USING THEM.  Ditto scientific notation.  

Today is 28 July 2008 -- Equilibrium chemistry

Scenario

You work for a company called, Merky Pharmaceuticals. Your team has been asked to give a presentation on how a new drug the company has developed. This drug helps to control the concentration of iron in the blood of people who have a genetic disease. The disease suppresses the protein that regulates blood-borne iron. Your team has been asked to present a 10 minute explanation of chemical equilibrium. Your audience is the stockholders. Most of them know little about chemistry except for the chemistry they took in high school.

Background

Many chemical reactions take place in our blood. We will look at the basics of two kinds of reactions that our blood performs every day: buffering and iron balancing. Buffers in our blood prevent our blood from becoming too acidic or too basic. When we exercise, for instance, the acidity of our blood tends to increase. If the acidity isn’t controlled, then all kind of nasty things can happen. Our blood contains chemicals that remove excess acids.

The amount of iron (in the form of iron ions) in our blood needs to be regulated chemically. We need just the right amount of iron to make hemoglobin that carries oxygen to every cell in our body. When the level of iron gets too high, chemical reactions remove iron from the blood. When the level of iron gets too low, other reactions occur that add more iron to our blood.

How can substances like acids and iron be removed? What does that mean? How can something as small as an ion of acid or iron be removed? (Very small tweezers?)

How can more iron be added to our blood? Do chemical reactions occur that release the iron trapped in substances in our body? How do these substances “know” when to release and when to capture the iron?

In this lab you will study a chemical law known as equilibrium. A French chemist by the name of Henri Louis Le Chatelier made sense of the rather complicated mathematics surrounding chemical equilibrium. In this lab you will see how equilibrium is applied in two chemical systems and use Le Chatelier’s Principle to interpret what you will experience.

Materials

For Part I -  Per Group            For Part II -  Per Group

Quantity            Item            Quantity            Item

1 dropper bottle            Fe(NO3)3  (0.045M)            1 dropper bottle            HCl (0.1M)

1 dropper bottle            KSCN (0.002M)            1 dropper bottle            NaOH (0.1M)

1 dropper bottle            deionized water            1 dropper bottle            acetate buffer

            Small crystals of KSCN            1 dropper bottle            bromcresol green indicator solution

            Small crystals of Na2HPO4           

1            24 well plate or spot plate                       

1            small plastic cup or 125mL beaker           

1            scoopulas           

1            beral pipet           

1            plastic stirrer           

Tasks

Part I: Can reactions go in reverse?

This lab will follow a format different from the format used in other labs. Begin by writing the names of the two ionic compounds used and write down the two kinds of ions in each of the two substances. Then read the directions at the right and write down your observations or responses on the left, as you go along step by step.

Part I

Name of Fe(NO3)3

Color:                          

Name of KSCN         

Color:           

Step 1: Place 45 drops of the KSCN solution into the plastic cup. Place one drop of the Fe(NO3)3 solution into the plastic cup, and swirl the cup to mix. On the report sheet write down your observation. Your teacher will help you determine the chemical equation for the reaction.

Step 2: Use the beral pipet to separate the contents of the plastic cup into 4 wells of the spot plate. You want to separate the solution so that all the wells will look the same color. Don’t completely fill each well, and you may have some solution left over.  Well #2 will be the reference, so that you can compare the color changes in the other wells to it.

Step 3: Add one or two tiny crystals of KSCN to well #1. Stir gently with a stirrer. Compare the color in well #1 to the reference well #2. Record your observation on the report sheet, and answer the question for step 3 on the report sheet.

Step 4: Add one drop of the Fe(NO3)3 solution to well #3. Stir gently with a clean stirrer. Compare the color in well #3 to the reference well #2. Record your observation on the report sheet, and answer the question for step 4 on the report sheet.

Step 5: Add one or two tiny crystals of Na2HPO4 to well #4. Stir gently with a clean stirrer. Record your observation on the report sheet, and answer the question for step 5 on the report sheet.

Clean out the well plate. Your teacher will give you directions.

Your teacher will give you directions for the debrief of Part I.

Ions present in solution    

+  Ions present in solution 

+   SCN- 

          

Step 1: Observation:  

         

Chemical Equation:           

Step 3: Observation           

Step 3: If cell #2 turned darker, more FeSCN2+ was produced. Which reactant, Fe3+ or SCN-, must have been present in excess in well #2 before you did step 3?           

           

Step 4: Observation           

Step 4: If cell #3 turned darker, more FeSCN2+ was present.

Today is 11 August 2008 -- Comprehensive Calorimetry Experiment Report

We conducted an experiment about heat capacity.  Specifically we investigated the calorie content of different foods.  Here is a very well written lab report covering the experiment.  The"Reference" section needs more detail, however.  Please study the report and you will learn both how to write a lab report and you will understand a lot about the energy content of substances. 

I.  Purpose:  To determine the heating value (calorie content) of various substances, especially foods.

II.  Materials:  1.  Known volume of water in 250 ml Erlenmeyer flask

                         2.  Thermometer

                         3.  Known mass of vegetable oil (approx. 2 grams)

                         3a  Food-stuff or other combustible material (about 2 grams)

                         4.  Watch glass

                         5.  Cotton wick

                         6.  Apparatus stand and flask clamp

III.  Procedure: A.  Introduction:  The word calorimetry comes from the Latin word "Calor" meaning heat, and "-metry" meaning to measure.  The method depends on burning a known mass of something as fuel and recording the increase in temperature of a known mass of water.  The calorie is a unit of heat energy that is defined at the amount of heat required to raise the temperature of one gram of water (initially at 4 degrees Celsius) by one degree.  Thus, ten calories is the amount of heat to raise ten grams of water by one degree, or one gram of water by ten degrees.  Starting with water at its freezing point, it would take approximately 100 calories per gram to raise it to its boiling point.  To evaporate water at its boiling point takes an additional 540 calories per gram. 

                           B.  Method:  In this experiment, some students will measure the heat released by burning vegetable oil.  Other students will use a small amount of vegetable oil (weighed) as a fuel to start another substance, such as a corn chip, etc., to burn.  All materials are carefully weighed and the masses recorded in the student notebooks.    In all cases, the results will be expressed as "calories per gram."  The heat that is released by the combustion is used to raise the temperature of a known amount of water in a flask.   The final temperature of the water in the flask is read and from it is subtracted the initial temperature.  This temperature difference multiplied by the mass of the water in the flask represents the amount of heat liberated by the fuel in calories.  (In the event the fuel is very energy-rich, or if too much fuel is used, the water in the flask may boil.  In this case, the amount of liquid evaporated in grams must be determined (by subtraction from the amount initially present) and that difference must be multiplied by 540 calories to determine the amount of heat released by the fuel to vaporize the water.  That amount of heat plus the amount of heat to raise all of the water to the boiling point from the starting temperature is the total heating value of the fuel.

                          C.  Example:  50 ml of water initially at 22 degrees Celsius is heated by burning vegetable oil.  The amount of oil initially present was 5 grams.  When the experiment was stopped, 1.5 gram of oil remained and 10 ml of water had evaporated.  What is the heating value of the oil? 

IV.  Results:        Ans:  From the statement of the problem, we know that 10 ml of water, or 10 grams, had been converted to vapor.  Since it takes 540 calories per gram to evaporate at the boiling point, we know the amount of heat to evaporate the water was 540 cal/g X 10 g = 5,400 calories.  We also know that we started with 50 ml (50 g) of water and this went from 22 degrees to 100 degrees, a difference of 78 degrees.  We multiply 50 g X 78 degrees X 1 cal/degree/g = 3,900 calories.  We add 3,900 calories + 5,400 calories to get 9,300 calories.   The amount of oil that was burned was 5 g - 1.5 g = 3.5 g.  Dividing 9,300 calories by 3.5 g yields a heating value of 2,657 calories per gram of oil. 

V.  Error Analysis:  Some heat was lost to the surroundings because the experiment was not conducted inside of a thermally insulated calorimeter.  To give support to the oil as it burned, a cotton wick was used.  Combustion of the wick may have added a little energy to the water as it heated.  Combustion of the oil was not complete.  We know this because a layer of soot accumulated on the bottom of the flask.  Had the oil burned completely, there would not have been the soot layer and more water would probably have evaporated. 

VI.  Conclusions:  To a first approximation, this experiment allowed us to calculate the heating value, or enthalpy, of oil.  Had we used a mix of oil and a food, we could have used the data to determine how much of the heat came from the food and how much came from the oil. 

VII.  References:  Holt Chemistry

Today is 7 October 2008 -- Who are some of the "Greats" of early 20th century chemistry?

Jonathan C. researched several as part of a class project.  Here are his findings:

John Dalton- he is best known for his work in the development of modern atomic theory, and his research into colour blindness also known as Daltonism. a lunar crater was named  after Dalton.

Albert Einstein- received the 1921 Nobel Prize in Physics for his services to Teoretical Physics and for his discovery of the law of the photoelectric effect. he is also known for his theory of relativity and mass-energy equivalence, E =mc ².

Wolfgang Pauli- found that the current idea that it was magnetic moment of the core of the atom that was responsible for the splitting of the electron energy levels pf the outer electrons was incorrect. proposing a new model, his famous exclusion principle.

Friedrich Hund- discovered an observational rule of atomic chemistry, Rule of Maximum Multiplicity. This rule is used in atomic chemistry, spectroscopy, and quatum chemistry.

Niels Bohr- developed the "planetary" model of the atom. The model introduced the concpet of electron motion to the atomic model.

Amedeo Avogadro- found a resolution to the confusion surrounding atoms and molecules. he believed that particles could be composed of molecules and that molecules could be composed of atoms.

J.J. Thomson- discovered an even smaller and more fundamental partical called the electron.

Dmitri Mendeleev- found that by listing elements in order of increasing relative , their properties recurred in a periodic pattern.He proposed the periodic law and arranged early versions of the periodic table.

Today is 24 October 2008 - Here is practice for the biology Standard Assessment Test

These questions provide practice to assist the biology class to prepare for the Standard Assessment Test.  The questions are similar to those which are on the test, but they are not the same questions.   

1.  What are the following:

a.  Viruses

b. eukaryotic bacteria

c. prokaryotic bacteria

2.  What is an “organelle?”  What do the following organelles do?

a.  ribosome

b.  mitochondrian

c.  Golgi apparatus

d. nuclear membrane

3.  What is the difference between eukaryotes and prokaryotes?

a.  nucleus

b. protein coat

c. cell membrane

d. ribosome

e. ribosomal RNA

4.  What happens during the dark phase of photosynthesis?  What happens during the light phase?

5.  What do each of the following do?

a.  bases

b.  sugars

c.  fatty acids

d.  amino acids

6.  What is active transport?  Does it require or give up energy?

7.  What is facilitated diffusion?  Does it require or give up energy?

8.  What are the steps involved in protein synthesis? (I gave you an illustration of this.)

9.  Why do different cells have or make different proteins?

10.  What would produce an inactive protein that is smaller than it otherwise should be?

11.  Beside structural functions, what else do proteins do?

12.  What is a “codon?” Explain what a mRNA codon does or pairs with during translation.

13.  Dr. Frankenstein has spliced plant genes for chloroplasts into the chromosomes of termites.  His theory is that when the chloroplasts are exposed to sunshine, they will produce food for the termites so the insects will not need to bore into structural wood for food.  Where can you find reliable information on risks or benefits of his idea?

a.  T.V. news or radio talk shows.

b.  Internet news and blogs, especially “stop.com” (Stall Termites On Photosynthesis) 

c.  Science journals where other researchers analyze Dr. Frankenstein’s work.

d.  Igor, a spokesman for Dr. Frankenstein.

14.  What are proteins composed of?  Can different proteins (that is, different functions) contain the same number AND sequence of these components?

15.  In class, you chewed a cracker until it tasted sweet.  You learned  that the enzyme “amylase” in your saliva broke the starch in the cracker down to simple sugars.  What would taste sweet faster:  chewing a whole cracker all at once, or nibbling a little piece?  Why?

16.  What precisely do ribosomes do?  (Detailed explanation)

17.  If you have a skin condition, some doctors recommend soaking in salt water?  Why?  On the other hand, what would happen if you soak in distilled water?   What does this suggest to you about the balance of salts in or out of body cells?  What would happen if we soaked a stalk of celery in salt water?  In distilled water?

18.  We demonstrated how DNA is transcribed to messenger RNA which then travels to the ribosome.  At the ribosome, transfer RNA’s bearing amino acids bind to the mRNA bases such that a guanine on the tRNA binds to an cytosine on the mRNA, and an adenine on the tRNA binds to a uracil on the mRNA.  It takes a set of three bases on the mRNA, called codons, to bind to three opposite bases on the tRNA, called anticodons.  Find a genetic code chart in your book.  If the anticodon is Adenine-Adenine-Adenine (abbreviated AAA), what amino acid is specified by the codon?

19. Antibiotics lose effectiveness when bacteria mutate.  Surviving bacteria then grow to recolonize an infected site.  If the genetic material (genome) of the original bacteria is a little different from the genome of the now resistant organisms, what does that tell you about mutations?

20.  Sketch the process of protein synthesis starting with the double helix of DNA.

21.  Sickle-cell anemia is caused by a mutation that changes the DNA sequence from CAT to CTT.  Then, the mRNA codon sequence changes from GUA to GAA and the amino acid that is specified changes from Valine to what?  Use the genetic code chart in your book to find out.

22.  What is “genetic engineering?”  What are some of the success stories due to genetic engineering?

23.  What do the following organelles do?

a.  nucleolus

b.  ribosome

c.  lysosome

d.  mitochondrian

24.  How important is it to be accurate when you observe science experiments?

25.  When you study figures, understand them thoroughly before working on the problem that they serve to illustrate.

26. Viruses are a little like aliens in horror stories.  Once they infect you, they can add their genetic material to your own.  But they can lay dormant for years and, since their genetic material is mixed with yours, it can be transferred to subsequent generations.  What does this tell you about trying to “breed” infection out of a plant or animal? 

Today is 6 March 2009 -- . This note is about the salt dissolving experiment

The experiment was to see if a change in dissolving time occurred as more and more salt entered the solution.  This is one aspect of solution chemistry.  Three different water temperatures were studied; cold, room temperature and hot.  Students added about 7 grams of table salt, sodium chloride or NaCl,  to 100 ml of water, stirred until it dissolved and timed how long it took.  They weighed the container of water before and after.  The difference in weight was how much salt they had added.  Then they repeated this with another approximately 7 grams, stirred, timed and weighed.  They repeated it a third time.  The results were to be graphed as the total weight of salt on one axis and the dissolving time for each salt addition on the the other axis.  For example, let us say the first 7 grams took 50 seconds to dissolve, the second 7 grams took 62 seconds and the third took 72 seconds.  The student would make marks at the intersection of 7 g and 50 sec,  14 g (7g +7g) and 62 seconds and 21 g (7g + 7g + 7g) and 72 seconds.  This example shows that as more salt is added to the solution, it takes longer to dissolve.  What would it mean if less time was taken?  

Some students used three different temperatures of water and attempted to plot that data.  That was incorrect and the data was worthless.  They were to use the same water temperature; either cold, hot or room temperature, and add salt to it.  By comparing data between different groups of students, testing at different temperatures, the class was supposed to determine if hot water dissolved the salt the fastest and cold water the slowest, or some other way.  

Today is 6 July 2009 -- We started our study of chemistry

We:

1.  Prepared a self-study questionnaire and guide.  This guide reflects how you have been studying.  It is what we call a "reflection."  That means we thought about the question and wrote down the way it is for us now.  You were asked to keep the guide.  In a few weeks, we will revisit it and see if your study methods have changed (improved?) based on understanding how you can best study.

2.  Made "notebooks."  The notebooks are for use until we make more permanent ones.  They involved folding a cutting a couple of pieces of paper to make an 8-page booklet.  Always, always, always put your name, date and (when applicable) period/subject on the notebooks.

3.  Read chapter 1 in "Cartoon guide to Chemistry."  This chapter discussed the history of chemistry.  Quick!  What was the very first chemical reaction to impress our ancestors?  (NOTE:  The history of chemistry, even though very briefly presented in the "Guide," is something all chemistry students should know.)

4.  Learned how to "preread."    We will go into more detail when you get your textbooks, and practice summarizing from books, but until then, go over ch. 1 of the Guide again, tomorrow.  This time, use the hints you learned from the "preread" sheet to take notes in your notebook on ch. 1.

5.  Discussed how to write a lab report.  There are 7 parts.  These are (a) statement of purpose, (b) materials and equipment, (c) procedure, (d) results with data, etc., (e) error analysis, (f) conclusions and recommendations, and (g) references. 

6. Had chance to start writing a lab report.  You titled it "The Hollow Penny," which was great title.  You learned how to use a triple beam balance to weigh a penny, then you learned the chemical reaction that would be involved (What was that reaction?) and you carried it out.  You saw the reaction start and you understand that it will go overnight.  You learned how to calculate dilution of an acid, and that the class of compounds called "salts" are composed of a metal and a nonmetal.  You began learning symbols for chemical elements and that the symbols used today are nowhere as complex as the symbols used by early alchemists.

We also discussed how many elements the ancients thought there were (earth, wind, fire and water), and how they realized there was something missing -- something mysterious that they named the "quintessence."  (You should define this, if you don't remember what we said in class.) 

We played with syringes to learn about air pressure. 

We also started talking about how to balance chemical reactions and what happens when something is "oxidized," or burned.  That led into the discussion of the different kinds of "airs" that Joseph Priestley discovered and we mentioned nitrogen, carbon dioxide, hydrogen and oxygen.    Other elements we mentioned today were zinc, sodium, gold, potassium, iron, bromine, chlorine, fluorine and iodine.  (Please make sure you know the symbols for these elements and compounds.) We said a few words about the "father" of the periodic table, Demetri Meendelev.

For tomorrow, we will finish the hollow penny experiment.  You will need to dry and weigh what's left, then write up your report.  

Today is 8 July 2009 -- We learned basics of scientific measurements

You used the "Hollow Penny" lab as a model for studying measurement.  You reweighed your penny and subtracted the final weight from the initial weight.  This gave you the amount of zinc that reacted with the HCl to produce hydrogen gas (H2) and ZnCl2.

We used this information in a discussion of density (density = mass divided by volume) and an introduction to the mole concept (moles = mass divided by atomic mass).  I explained that the mole referred to a specific quantity, like a dozen means 12, and a pair means 2.  I put the following words on the board for you to know:  meniscus and stoichiometry.  We also used the words divisor, density, limiting reagent, coefficient.  (PLEASE LEARN THESE WORDS AND THEIR MEANINGS).  You learned a little about the metric system, that 1 ml = 1 cubic centimeter (cc), and the prefixes:  mili = 1/1000, centi = 1/100, and deci = 1/10.  We gave examples like cent in century, or as in 1/100 of a dollar, and centavo, as 1/100 of a peso.  Millennium has the root "mil" and means 1000, as 1000 years.  Deci means "10" and is the basis of the decimal system. 

I showed you how to solve problems using addition (decimal points line up) or subtraction, and multiplication (with a brief introduction to scientific notation).  You learned that to divide numbers, the denominator (bottom number in a fraction) goes into the numerator (top number). 

We modeled dilution of an acid.  In particular, we had 37% hydrochloric acid (that is hydrogen chloride dissolved in water) and we diluted 20 ml of it to 100 ml with pure water.  That is what we used in the penny lab.  You solve it like this:

                    37%   100 ml

                   ----  =  ------

                     x       20 ml

Cross multiply and divide by 100   for x = (37%)(20ml)/(100ml) = 7.4%

You used the information on the weight of Zn that reacted with the acid solution to calculate the number of moles of zinc.  From there, you calculated the number of moles of ZnCl2.  Then you found the atomic weight of ZnCl2, multiplied it by the number of moles present and obtained the mass (in grams) of the ) ZnCl2. 

Today is 8 July 2009 -- We learned "historical chemistry"

We need to remember that chemistry has taken centuries to develop to its current state, and that it continues to evolve.  It is important to know of past accomplishments and how they impact the present as well as the future.  

Who was John Dalton?  Of Dalton's Laws, how many remain unchanged?  When did he formulate his ideas?  Who was Neils Bohr?  What did he do?  Remember, he was dyslexic and still accomplished much.  We discussed atomic structure and the relative size of an atom.  Quick!  If the nucleus was the size of a marble, where would the first electron be?  You learned about atomic number, atomic mass, protons, neutrons and electrons.  You also learned how to find the number of neutrons when the atomic mass and atomic number were known.

We discussed how chemical formulas are written.  For example, when ammonia NH3 (a gas) dissolves in water, it forms ammonium hydroxide, NH4OH.  That compound ionizes to form NH4(positive) and OH(negative).  They react with, for example, sulfuric acid, H2SO4 to form (NH4)2SO4 (where that "2" outside the parenthesis is also a subscript), and water.  

We started discussing scientific notation, significant figures, dimensional analysis (or unit conversion factors), the meaning of the mole and Avogadro's number.  I mentioned that one way of remembering Avogadro's number was to think of it as a telephone number:  "Ava  Gadro:  602-1023."

We saw just how big a number Avogadro's number was in comparison to the number of seconds since the universe formed `13.6 billion years ago:  4.688E17 compared to 6.02E23. 

A student came up with a clever way to remember the rows and columns of the periodic table:  "You climb a column, but run a row!"

You had a brief essay question to ponder:  "From your 'prior knowledge,' of chemistry and what you have been learning in this class, suggest a way to organize elements in some way OTHER than the current idea of the periodic table."

For homework, you were asked to develop your name (or other word) using periodic table symbols, and to send them to me at "abinc@aol.com."  I said I would print them onto thermal paper so you could transfer them to a garment.

Finally, we began to review the text (HOLT, Chemistry), Ch. 1 and 2.  You were asked to study the figures, the tables, the vocabulary and the highlighted words.  REMEMBER TO BRING YOUR BOOK BACK TO CLASS EACH DAY.