Human Biology: Organic and Biochem

Anna and I have been reviewing Organic Nomenclature WS 10.4 (Key), Organic Nomenclature 10.7 (Key), Biochem Basics (Key), and Organic Functional Groups.  Some of the material is review.  We invested several classes reviewing them basics.

Apologia Chemistry: Extra Labs and Activities for Atoms

Three of the kids in my class of eight have finished the Stoich lab and are writing up the lab report.  The two boys at SeaPearch will do the lab Tuesday.  Three other kids are still doing mole problems and are not ready for the lab.  Everyone is going to do the POGIL Nuclear Atom activity at home.  (I had hoped to do it together in class. (Key))  On Tuesday, the three kids who have finished the Stoich lab are weighing the precipitate and calculating the percent error.  Then, they are doing two labs and filming demos for the rest of the class.  (I'll post the videos when they finish.)  The two labs are Drawing a Scale Model of the Atom and the experiment in Module 5 Measure a Molecule (This link is similar to the lab in the text.  The kids will follow the directions from the book.)  The kids will do the labs and debate what the labs mean before they film demos.  These three are substantially ahead of the rest of the class.  I like to give kids in this position meaningful activities.

During my career, I filmed labs frequently.  (I had release forms I distributed at the beginning of the year.)  Kids like to film.  I upload the videos to my Youtube channel; I can embed the videos into the blog.  Videos are an excellent way to assess understanding of any topic.  I used to film kids during lab and ask them to explain the purpose of the lab.  Consider making a video as an alternate assessment in your class.

Science Kits

Good Will has a Chem Kit listed; it’s current bid is $65.  It is a fair value because it has a ring stand, glassware, and useful supplies, such as a weigh boat.  It does not appear to have a digital scale or thermometer. It is over-priced.  However, if you do need basic equipment, this kit is priced fairly and includes most of the basic materials for lab.  Compare the Good Will kit with this eBay Labpaq kit.  The eBay kit has a digital scale ($8 on Amazon) and a thermometer ($8 on Amazon).  The eBay kit has a burner stand—not a ring stand.  The bottom line is to price the kits based on their contents of equipment and compare prices on Amazon.  I like to pay about $30 with shipping for an eScience or Labpaq Kit.

Lab Report Rubric and Instructions

The Stoichiometry lab, Can You Make 2 Grams, is a good opportunity to assign a formal lab report.  My goal is to assign four reports this year; this is the second one.  Lab reports are good examples of technical writing.  For this lab, the kids need to research Stoichiometry and moles to include in the background section of the lab.  Lab reports may be organized into sections.  However, each section should be written in paragraph format using the third person, present tense, active voice, and indicative mood.  Below is my rubric.  I will post good examples next week.

Here is the lab report rubric.
Lab Report Rubric


1. ________ (10 points) Title of lab report

2. ________ (10 points) Background information (Use the third person, present tense, and active voice.)

3. ________ (10 points) Materials listed in paragraph format.

4. ________ (10 points) Procedures described in paragraph format. 

5. ________ (10 points) Balanced equation for the reaction

6. ________ (10 points) Results. Use paragraph format and state what happened. Include the percent error.

7. ________ (10 points) Discussion.   Discuss the percent error and possible sources of error.

8. ________ (10 points) Conclusion.  How could the lab be modified if repeated?  (More trials are indicated.  More study is needed.)

9. ________ (10 points) Correct grammar, punctuation, spelling, person, voice, tense, and mood.

10. ________ (10 points) Cite all sources of information including the textbook and the lab packet.

Apologia Chemistry: Can You Make 2 Grams Lab

Yes, I do realize I have already posted several times about the 2 Grams lab.  Here is another example with the steps.
1.  The reactants are zinc sulfate heptahydrate +  potassium carbonate
2.  Write the equation for the double replacement in words.
zinc sulfate heptahydrate + potassium carbonate ----- zinc carbonate  + potassium sulfate  + water
3.   Write and balance the equation  (Number 4 in the answer key)
  ZnSO4 • 7H2O  +   K2CO3   -------    ZnCO3   +   K2SO4   +  7 H2O
4.  Identify the precipitate zinc carbonate.
5.  Convert 2 grams of zinc carbonate into moles (0.01595 moles)
6.  Determine the number of moles of each reactant; in this example, there is one to one mole ratio.  0.01595 moles of zinc sulfate heptahydrate and 0.01595 moles of potassium carbonate.
7.  Convert moles of each reactant into grams, 4.59 g zinc sulfate heptahydrate and 2.20 g potassium carbonate.
8.  Dissolve each reactant separately into 25 mL of water, combine the two reactants, and filter the precipitate.

Once the kids finish the lab and recover the precipitate, they will dry and weigh the precipitate.  Then, they will write a formal lab report which include the balanced chemical reaction, data, and percent error.  Hopefully, everyone will finish this lab in early February.

Apologia Chemistry: Module 6 Moles and Stoichiometry

Today is typical in the life of Home-school Co-ops.  Two of the kids are at the Marine Corps Museum building under water robots. (Seaperch). Three kids are present who missed class last week.  One kid was present but still struggles with the material.  Sound familiar?  I did a quick review of the germane mole and Stoich. concepts.  I gave two kids the Can You Make Two Grams lab.  I gave the other kids the empirical formula quiz we did last week—after a quick review of empirical or molecular formulas.  For the remainder of class four of the kids worked on last week’s homework assignment here while the other two worked on the lab.  Next week, the two guys at Seaperch will start the lab.  Arrrrggghhhh.

Chemistry Kits

Chemistry kits vary in quality.  Thames and Kosmos is a good example.  (Here is more retail information.).  Good Will often has chemistry kits.  I am not tempted.  Take a hard look at the kits.  Usually they do not have much equipment such as beakers, flasks, or thermometers.  The Thames and Kosmos C3000 Kit includes a clothes pin.  (A clothes pin can serve as a test tube holder or tube clip.). When I evaluate a chem kit, I ignore the chemicals.  Chemicals degrade; their shelf life is about five years.   This type of commercial chem kit is more of a toy than a tool.  Compare commercial chemistry kits with Labpaq Chem Kits.  The Labpaq kits offer more equipment; this example has a digital scale and glassware.  Here are a few key terms I use to search for kits on eBay or Good Will: ‘lab kit’, ‘science kit’, ‘Labpaq’, ‘eScience’, ‘microchem’, or ‘chem Kit’.  By all means try Facebook Marketplace or other e-commerce sites.  I have had the best luck with Good Will and eBay.  Don’t forget to check the prices on Amazon!

Apologia Chemistry: Module 6 Stoichiometry Can You Make 2 Grams Lab

Can You Make 2 Grams from Flinn Science is one of the best labs for high school chemistry.  The lab itself is quick once the kids finish their calculations.  Each kid gets a different pair of reactants and must determine the number of grams of each reactant necessary to product two grams of a precipitate.  The kids prepare the two reactants in 25–50 mL of water and combine.  The precipitate may be recovered with gravity filtration.  I use a filtering kit with a vacuum pump—much quicker.  Amazon’s Kit is $60.  (Guess where I bought mine?  Yes, Good Will.). $60 includes the pump, Büchner funnel, and a side-arm flask.  The side arm flask can be used for this Charles Law lab when you study Gas Laws.  I’ll post pix next week when we do the lab.

E-science Lab Kits

Good Will and eBay frequently have eScience lab kits available.  These kits are designed for online college science kits.  They can retail for $150.  I like the Bio and Chem kits.  I am buying the kits for their contents: cylinders, beakers, pH paper, thermometers, etc.  Usually I pay around $30 (with shipping) for these kits.  Look at several on eBay to compare prices and contents.  These kits are good values for families looking for basic science equipment.

Apologia Chemistry: Moles Mop up Modules 5 and 6

The kids took a quiz on empirical and molecular formulas first.  Then, we mopped up.   Modules 5 and 6 have moles and Stoichiometry.  Topics include mass to mole conversions, moles to mass conversions, moles to atoms or molecules, percent composition or percent by mass, molar mass, and empirical and molecular formulas.  The kids are working on sample problems.  Next week, we hit the ground running with Stoichiometry in chemical equations.

Sensors

Good Will has a CBL kit recently listed.  The CBL2 system is a data devise.  It collects data with probes.  I have used several types of CBL devises.  Most CBLs connect to TI 83/84 calculators.  The data collected through the CBL is stored in the Stat tables, L1 or L2.  Even if the CBL does not function, there are several probes included: temperature, light, and voltage.  eBay  has an older version of the CBL for about $20 and CBL 2  for around $30.  I would not pay more than $30.  The three probes are worth around $30; there is not guarantee the CBL works.  More often than not, the probes work well.  The probes can be used with TI84 and Vernier’s Easylink. (Here  are the probes compatible with the TI84 and Easylink.). Often, I use TI 84 calculators with temperature sensors in lab.  Remember, when you bid on a kit or set, determine what you can cannibalize from the kit.  Usually, I restrict my bid to about $20 (including shipping) for kits and sets similar to the CBL kit.

Apologia Chemistry: Module 6 Stoichiometry Can You Make 2 Grams Lab

Once the kids do some more mole problems, we are doing Flinn's Can You Make 2 Grams lab.  (Here are pre-lab calculations.  Here are the reactants for the lab and the answer key for each reaction.)  Each kid gets a different pair of reactants.  Below are the steps for the lab.  I plan to post lab reports and issues which arise next week.

Step 1: Write the number and reactants in the lab notebook.
 #6: magnesium sulfate heptahydrate + sodium carbonate
Step 2: Write and balance the equation.  All of the equations are double replacement reactions.
  magnesium sulfate heptahydrate and sodium carbonate yield magnesium carbonate and sodium sulfate and water.  (See page 2 and 3 for the answers with the balanced equations.) 
Step 3: Identify the precipitate formed.  (The sulfate or carbonate products are the precipitates.)
The precipitate for #6 is magnesium carbonate.
Step 4: Convert 2 g of MgCO3 into moles.  2g/84 g/mol = 0.238 mol
Step 5: Determine the ratio.  The ratio for each reactant is 1:1.  Therefore 0.238 mol of magnesium sulfate heptahydrate require 0.238 mol of sodium carbonate.
Step 6: Convert the moles of each reactant into grams.
   0.238 mol x 246.50 g/mole = 5.85 g
   0.238 mol x 105.99 g/mole = 2.51 g
Step 7: Prepare the two reactants.  Add each to 25 mL of distilled water.  Combine the two solutions, filter the precipitate, and allow to dry.
Step 8: Weigh the dry precipitate.  It should be about 2.0 grams.  If the sample is more than 2 gram, it is still wet.
Step 9: Calculate the percent error.
Step 10: Write a formal lab report.Here is a similar report.

Apologia Chemistry: Module 6 Stoichiometry--Even more practice problems!

Stoichiometry is tricky.  Students struggle with this module.  Period.  Here is an example with the steps for the solution.  (Here is another stoichiometry worksheet with answers.) 

For the following unbalanced equation, calculate the number of grams of copper (II) chloride would be required to react completely with 25.0 grams of magnesium.
Mg  +   CuCl2 ------  MgCl2  +   Cu 
Step 1: Balance the equation.  This equation is already balanced.
Step 2: Convert grams of magnesium into moles
         25.0g/24.3 g/mol = 1.0288 mol
Step 3: Determine the mole ratio.
   Mg  +  CuCl2  ------MgCl2  +  Cu
   1 mol   1 mol 
One mole of magnesium requires one mole of copper (II) chloride.
Step 3: There is a 1:1 ratio; 1.0288 mol of Mg require 1.0288 mole of CuCl2.
Step 4: Convert the moles into grams.
   1.0288 mol of CuCl2  is 1.0288 mol x 134.446 = 138.318 g of CuCl2



For the following balanced equation, calculate the number of grams of sodium hydroxide would be required to react completely with 25.0 gram of sodium bisulfite.
NaHSO3   +   NaOH ------- Na2SO3  +   H2O
Step 1: Balance the equation.  This equation is already balanced.
Step 2: Convert 25.0 grams of sodium bisulfite into moles
      25.0 g/104.01 = 0.24 mol
Step 3: Determine the mole ratio.
         The mole ratio is 1:1  There is 0.24 mol of NaOH
Step 4: Convert the moles into grams.
   0.24 mol x 40.01 = 9.6 g NaOH


For the following equation, calculate the number of grams of boron produced from 15.0 grams of boron trichloride.
BCl3  + H2  -----  B + HCl
Step 1: Balance the equation.
2BCl3  + 3H2 ----- 2 B  + 6HCl
Step 2: Convert 15g of BCl3 into moles
    15/117.16 = 0.128 mol
Step 3: Determine the mole ratio.
   2 mol BCl3  produce 2 mol B  2:2 or 1:1 ratio
   0.128 mol BCl3 produces 0.128 mol B
Step 4: Convert the moles into grams.
  0.128 mol x 10.81 g/mol = 1.38 g B or boron

Apologia Chemistry: Module 6 Stoichiometry---More examples for Instruction

Over the past two weeks, we have discussed several disparate concepts in class.  Thursday, I want to clear up and tie concepts together.  First, I want to make sure the kids understand what operations I am asking them  to do.  This chemistry textbook has loads of examples. The answers are in parentheses.
1.  Convert grams of elements into moles.
    a. 63.45 g of zinc (0.9705 mol)
    b. 5.869 g of nickel (0.10 mol)
    c.  3.251 g of lithium (0.468 mol)

2. Convert moles to grams.
  a.  8.72 mole of carbon (105 g)
  b.  0.0125 mol of neon (0.252 g)
  c. 6.25 mol of aluminum (168.75 g)

3.  Calculate mass percent
  a. C10H14O  (79.95% C, 9.394%H, and 10.65%O)
  b.  Na2S (58.91% Na, 41.09% S)
  c.  PH3 (91.10%P, 8.896%H)

4.  Calculate empirical formulas
    a. A compound was analyzed and was found to contain the following percentages by mass: pho hydrogen 3.09%, phosphorus 31.60%, and oxygen 65.31%.  Determine the empirical formula of the compound.  (H3PO4)
    b.  A compound has the following percentages my mass: barium 58.84%, sulfur 13.74%, and oxygen 27.43%.  Determine the empirical formula of the compound.  (BaSO4)
    c.  If cobalt metal is mixed with excess sulfur and heated strongly, a sulfide compound is produced that contains 55.06% cobalt and 44.94% sulfur.  Calculate the empirical formula of the sulfide compound.  (Co2S3)

5.  Calculate molecular formulas.
   a. A compound with an empirical formula of CH was found to have a molar mass of 78g/mol.  What is the molecular formula?  (C6H6)
   b.  A compound with an empirical formula CH4O has a molar mass of 192 g/mol.  What is the molecular formula? (C6H24)6) 
   c.  A compound with 46.91% Na, 24.51% C, and 28.59% N has a molar mass of 50 g/mol.  Determine both the empirical and molecular formulas.  (Empirical is NaCN  Molecular is the same as the empirical formula NaCN.) (NaCN is sodium cyanide.)

Apologia Chemistry: Module 6 Stochiometry

Today, my goal was to teach a basic understanding of moles and stoichiometry.  The class began with a review of the equations from last week's Chemical Formula Lab.  The point was to help the kids see that the ratio of drops produces different ratios of the precipitate and clear solution.  We discussed the optimal ratios of the reactants and products which produced the most precipitate for each reaction.  The optimal ratio is the compound's formula. 

We used these four reactions to introduce stoichiometry.  Actually, before we used these equations, I used coins again to teach the concept of stoichiometry.  (Photos are below.)  I spent time showing the kids that the number of coins reacting equal the number of coins in the product.  We even calculated the total mass of the reactants and total mass of the products. 

I use one sandwich as a simple means to introduce Stoich. Once I was sure the kids understood that the coefficients in a balanced equation represent the number of moles of each reactant and the number of moles of product formed, I walked the kids through several examples.  Thursday we'll resume our work.  Stoich. is the hardest material to understand and apply.  On Thursday, I need to spend time on empirical formulas, too.  Below are pix of the examples we used in class.  The first two are the equations from the Chemical Formula Lab.  Go slowly!

Apologia Chemistry: Module 6 Empirical Formulas and Chemical Formulas

We reviewed empirical formulas before we did the Chemical Formulas Lab.  (Free lab is here.). The lab uses mole ratios, stoichiometry, and solubility.  I added a bit of reaction prediction.  I reminded the kids they need to know copper and iron use the stock system, cupric means copper (II), and ferric is iron (III).  I wrote out the reaction combinations and the kids predicted the products of the double replacement reaction—also precipitation reactions.  We have not studied solubility or solubility rules.  We have encountered loads of precipitates.  NaCl forms and is soluble.  The product which forms the greatest amount of precipitate has the mole ratio of the compound.  Tuesday, we need to finish debriefing the lab.

I have a huge bag of plastic test tubes which fit in standard test tube rack.  The lab is microscale; the reactants are measured in drops of 0.1 M concentrations.  The lab is safe and cheap.

Backyard Science

Our home is near Quantico outside Washington D.C.  Imagine loads of people and cars.  Yet, our backyard attracts a huge variety of birds.  We have one feeder.  (We have gone through many bird boxes; Mr. Squirrel and Mr. Raccoon knock them apart.  We plan to install a new bird box and bat box soon. )  Have you heard of Identiflyer Lyric or Birdsong Identiflyer?  The device plays birds calls.  Some birds answer the calls.  It can be helpful to identify the bird by its call—known as ‘birding by ear’.  You may want to start with birding apps, an electronic bird life list, or print a paper life list or check list.  (You may want to create a mammal list with a simple field guide.). Let me warn you; bird and bat boxes, feeders, etc. lead to Backyard Wildlife Habitats.  We have a small rain garden because the backyard is wet.  Our back faces a retention pond with several trees.  It’s enough. Children are often naturalists.  Winter is the time to make feeders.  I think wildlife identification is a terrific science supplement—especially if the kids research feeders and bird boxes.

Science Equipment

Good Will has Celestron LCD digital microscope available.  Note these microscopes are a gamble even if they power on.  Normally my kids use USB digital microscopes with a laptop to view slides.  This means the kids study microscopes at a low resolution.  Most of the time, this is enough.  Once in a while, such as mitosis slides, it’s better to use higher resolution microscopes.  N.B.  When the kids use high resolutions, they are more apt to scratch the lens; the kids forget and use the coarse adjustment and grind the lens into the microscope slide.  See why I use inexpensive digital microscopes?  I am still VERY tempted to bid on the Celestron microscope.  The local library has one for its Maker Space.  The resolution is amazing.  I find the librarians are reluctant to take out the Celestron microscope; they are expensive.  The result is few kids get to experience a good digital microscope.  I cannot rationalize buying one myself; I just want one very badly.

Human Biology: Organic Review

Anna and I are working through Biochemistry.  This week we are reviewing basic Organic nomenclature: Organic Naming WS (key) and 10.7 WS (key).  We began instruction with alkanes.  Organic chemistry nomenclature begins with alkanes because the base names, methane, ethane, propane, etc also form the basis for many substituent groups, such as methyl, ethyl, and propyl groups.  I always use these organic naming worksheets first; they include several means to represent the same compound. (Drawing Organic Molecules). Get out your molecular model kit.  Build the simple models first.  Anna and I have built a number of complicated models recently.  I built a simple model of hexane to show how the molecule is three dimensional; either end can be number 1.  Here are more instructions.  Go slowly and do loads of examples.

Apologia Chemistry: Module 6 Stoichiometry Empirical and Molecular Formulas

Today the class spent the entire period learning how to calculate empirical and molecular formulas.  We started with coins as a review.  We transitioned to compounds and instructions for determining empirical and molecular formulas.  Finally, we did some practice.  It took some time to get the kids to see the relation among percent composition, empirical formula, and molecular formula.  The kids try to memorize algorithms or steps rather than understand the concepts.  I go back to coins when they are confused.  For example, I show the kids combinations of quarters, dimes, and nickels and compare empirical and molecular formulas.  The kids know the respective mass of each coin, it’s molar mass.  I use the coins and their masses to help the kids apply the concept to chemical formulas.  No small feat.   We did examples in class and assigned problem sets to complete at home.  Kids need quite a bit of practice to master these.  I let the kids use their notes.
Here are the worksheets and photos. 
Worksheet 1. We did these in class.  The answers are at the bottom.

Worksheet 2. The kids are doing the first five problems for homework.

Quiz. Here is my quiz.  The kids should be ready for a quiz next week.

Apologia Chemistry: Articles

Most of my background teaching has been in private schools and home-school students.  I did teach in a public high school for several years.  The science teachers were instructed to increase the amount of reading and writing assigned to our students.  It was painful.  I learned that if the articles and writing topics were interesting the kids would participate.  I orders class subscriptions to ChemMatters.  I tried to devise interesting writing exercises.

1.  Should you get a tattoo?  We read Going Skin Deep and Tattoo Ink Chemistry.  In class we did a simple risk analysis by listing risks and benefits.  I asked the kids to write a paragraph to determine if the risks outweighed the benefits or vice versa.  They wrote volumes about whether or not a teen should get a tattoo.

2.  Otzi the Iceman and Bog Mummies.  How do scientists determine the age of accidental mummies?  

Start with this Smithsonian article about Otzi.  I like to show kids where the Dolomites are.  Then we discuss Radiocarbon dating.  How do scientists know Otzi’s mummy is 5300 years old?

3.  Money.  The Captivating Chemistry of Coins, The Money Makers (Scroll down.), Counterfeiting Counter Measures, and The Chemistry of Money.  It’s fun to look at US and international bank notes with a digital microscope connected to a laptop—which allows two or three students to view the images.  I ask the kids questions such as, ‘How do governments deter counterfeits?’  ‘How can you detect fake bills?’  Here is a question from the October 2019 of ChemMatters.  ‘  

9. Digital currency and transactions (credit and debit cards, Venmo, online banking, etc.) have reduced the use of paper bills.  What are the pros and cons of using digital currency and transactions compared to traditional cash?

Students answers will vary, Examples

Pros:  Limits counterfeiting of paper money, Do not have to carry cash, Reduced cost for government to produce new money.

Cons: Cyber crime, fraud, identity theft, stolen information, prone to technology issues and failures.’

Ask the class if cash should be eliminated.  This should produce a lively discussion.  Do a brief risk analysis and have the kids list risks and benefits.  Do the risks outweigh the benefits or vice versa?

Apologia Chemistry: Empirical Formulas and Molecular Formulas WS

Next week the class is working through empirical and molecular formulas.  They are going to do problem sets.  The quiz will reflect the problems.  We’ll start with these worksheets (with answer keys).  Here is a worksheet with percent composition, empirical formulas, molecular formulas and an answer key.  My tests include 10-12 problems.  Usually, we start these types of problem sets in class so I can answer questions and check results.  Sometimes, a kid understands the concept immediately.  I ask the child to do three problems to demonstrate mastery.  If he or she is successful, I give them the quiz immediately.  Problems sets are designed for practice—not punishment.  If the child takes the quiz and fails, he or she resumes practice and retakes the quiz.  Some kids do not need the practice.  If a child is struggling with problems, take out coins and practice using different ratios of quarters, dimes, and nickels.

Apologia Chemistry: Empirical Formulas and Isotopes or Beanium

Today, we reviewed Percent Composition with coins and empirical formulas.  I'm going to use the coins for several examples of empirical formulas next week and until I think the kids are gaining an understanding of empirical formulas.  We began with three quarters (5.7 g each) , two dimes (2.3 g), and one nickel (5.0g).  I walked the kids through the steps to converts the coins into percents by mass, then to convert the percents into moles, and finally how to compare the mole ratios back to the original empirical formula.  I plan to do several similar examples with compounds and coins next week to drive home the concept.

Then the kids did Beanium.  We discussed what an isotope is.  The reason I introduce isotopes and Beanium now is the kids are learning about percent composition in terms of empirical formulas.  Don't ask me why; I've learned that calculating weighted averages for an isotope in Beanium makes sense to the kids now when they are learning about empirical formulas.  I don't know of a good time to learn about isotopes.  The main point to Beanium is that all of the different types of beans are isotopes for the element, Beanium.  The kids submit neat lab tables and a definition of isotopes in their own words.  We spent time in class with talking about C-12, C-13, and C-14, their relative abundance in terms of the atomic mass.  I mentioned that C-14 forms in the upper atmosphere.  Next week, I want to assign Otzi the Iceman and Carbon dating.  The kids aren't ready for empirical formulas homework; I gave them an article to read, Feeding the World.  The kids are writing a summary paragraph.  Chemmatters are articles published by the American Chemical Society for high school students.  ACS has teacher's guides with background, questions, and lesson ideas.

Below are photos from class.  I'm trying to remember to take photos of the board as we work.  The Beanium photos are just evidence we actually do the labs cited here.

Apologia Chemistry: Back to School! Back to Moles!

The class spent most of the period reviewing the Percent Composition minilab and the the Weighing Moles lab.  We took the data and calculated the theoretical yield, experimental yield, and percent error for several hydrates.  We reviewed how to convert mass of elements and compounds into moles.

We spent the rest of the class doing What is Percent Composition? with quarters, nickels, and dimes.  I gave the coins to each child with a scale and asked what information they could derive.  The kids counted and weighed the coins.  They calculated the quarters as a percent of the total value and as percent by mass.  We did this for the nickels and dimes, too.  The idea is to understand empirical formulas.  Thursday, I am going to give the kids a combination of quarters and show how to use the mass percent to determine the empirical formula.  Here is a worksheet with an answer key.  I plan to do the Beanium lab and explain isotopes. 

Here are a few photos.  Note the  timelines below.  I like to include completed work as documentation our Co-op completes the work described.  As part of the timelines the kids has a worksheet and were to document the scientists' contributions to the development of the Atomic Theory.  Just as you would expect, I got some of the work--but not all of the work.  Sigh.  Thursday I will explain just what they are missing.  Again.