Practice Chemical Equations

 Lately, my kids have been writing equations for the Stoichiometry unit.  I noticed many formulas were incorrect.  Nomenclature, balancing, molar mass all rear their ugly heads over and over in Chemistry.  I made this worksheet, using equations from this worksheet to practice writing and balancing equations.(BTW this is normal teen behavior to want to move along and flush earlier lessons.)  Let me share a few resources: Flinn’s Ionic Formulas Chart, this Nomenclature post, and the  Acid Naming Song. Below are four videos explaining how to balance equations.  

Treasury X Aliens Ultimate Dissection

 Update: Top Secret Toys has Dissect-It: a frog, salamander, and piranha.  I just ordered the frog and salamander.  Paul is studying fish and amphibians in Science.  After the kits arrive, we’ll assemble them and dissect.  The Dissect-It kits are $14.99, less expensive than most synthetic frog dissection kits.

Paul, ten, and my husband, Rob, are extremely squeamish.  Both of them freaked over an Owl Pellet Dissection and get queasy over anatomy diagrams.  I’m bidding on a Treasure X Alien Ultimate Dissection toy and am considering this  Synthetic Frog Dissection kit.  (I bought a synthetic frog kit years ago; the refill goo is impossible to find.  I tried gelatin as a substitute, which just created a mess.)   Originally, I used the synthetic frog to demonstrate dissection procedures and the location of organs.  Since I want Paul to experience a dissection, it may mean using a toy.  Sigh. 

Stoichiometry Practice

 Today my kids are working on Stoichiometry—still.  We are using this equation worksheet.  The kids are balancing, naming, and determining the molar masses for each element or compound.  We use these reactions in class for Stoichiometry.  Before class, I sent the kids the worksheet and gave each student a different equation.  Each teen wrote, balanced, named and calculated the grams to make 5 g of product.  Below are examples with screenshots from class today.

Stoichiometry: Limiting Reactants

My Co-op Chemistry class is working on Stoichiometry, including limiting reactants.  I use both virtual and live labs for class.  I have been using virtual labs, simulations, and videos to supplement the online instruction.  PhET has this Limiting Reactant simulation.  Here is a video lecture about limiting reactants from TEKS.  Here is a virtual lab from ChemCollective.  These virtual labs help the kids get ready to do the Experiment 6.1, Limiting Reactants.  Here is a similar lab with baking soda and vinegar.  I will let you know how things progress.

Still More about Precipitates

One student worked through Precipitates and completed a list with the formulas of the ionic compounds.  He also wrote two of the solubility rules.  After your teen determines the formulas, look for generalizations.  For example, sodium compounds are soluble.  Below are the original chart and list of compounds one student submitted.  The others in the Co-op class are still struggling with the instructions.

Family STEM: Knitting

When you think STEM you probably don’t think about knitting.   We use math in recipes all the time.  Math multiples apply to knitting as well.  You have to use a bit of math to adjust 3 x 3 or 4 x 4 ribbing patterns or blocks of knit and purl stitches.  Here, here,  and here are articles about math and knitting.  Here is STEM and Knitting, the article I found the most helpful in terms of setting STEM challenges.   

Even More about Precipitates

 One aspect of Stoichiometry is predicting products and determining which product is a solid precipitate.  My Co-op class is working on Precipitate Reactions.  After the kids watch the lab video and complete the data chart, they should name all of the compounds.  For example Ag+ and Cl- form AgCl.  Next they use their data table to separate all of the compounds into two groups: precipitates and clear solutions.  Clear solutions are soluble; precipitates are insoluble.  Put aside those compounds which are slightly insoluble.  Instead focus on precipitates and clear solutions to identify patterns.  This exercise is a good review of ionic nomenclature.  This is the approach scientists take to identify patterns and form rules.  Below is a screenshot from the website for the virtual lab.

MEL Chemistry

 Did you have a flood of ads for MEL Chemistry kits before Christmas?  Good Will online has MEL kits listed quite often.  eBay has individual kits for around $20.  Many of the kits listed are unopened.  I bought two kits from Good Will and eBay.  Once we whittle down some of the other science kits, I will test them.  The image below is from one of the eBay listings.

Hot Ice

With all of the snow and ice outside my brain seems to be fixed in snow and ice experiments.   I have tried Hot Ice unsuccessfully. Here are the instructions from Frugal Fun.  Here are Steve Spangler’s instructions for Hot Ice using the sodium acetate chemical, instead of making your own sodium acetate.  I have had students try Hot Ice experiments with sodium acetate obsessively, with uneven results.  Here is an inspirational video.

The Benzoic Acid Blizzard and Instant Snow or Polysnow experiments work consistently.  

Precipitates

 Update: My kids are struggling with the idea of determining solubility rules.  After the kids watch the video from precipitates and complete the chart, I am going to have my class write the formulas.  Next, I’m going to have them make two columns: clear, cloudy, or solid.  Clear compounds are soluble: cloudy or solids are precipitates and insoluble.  Once, the two categories are complete, the kids will look for patterns to determine groups of compounds which are soluble.  I’ll let you know if this approach helps.

My Co-op Chemistry class is working through the exercises from TEKS, Precipitates.  My kids are creating the ion chart from the video lab.  Have your teen write the formulas for the ions and precipitates.  As I teach Stoichiometry, I review nomenclature, equations, reaction prediction, balancing equations, molar mass, and mole calculations—all the skills the kids have learned.  Below is one student’s chart.  See how your teen could write the formulas?

Biomolecules

 One key concept in Anatomy or Biology in general, is Biomolecules.  I bought this Lab Aid kit for my Biology Co-op classes.  The kit has packets or worksheets similar to this one (Key) for Biomolecules.  The class builds each molecules as they work to answer the questions in the packet.  Make clay molecules and use toothpicks for your Biomolecules.  Molecule kits are widely available on eBay, Good Will, and Walmart, Amazon for less than $20.  The time invested building molecules helps kids see and understand  the structures.  The molecule below is built from the Lab Aid kit.

Chemistry Lab Kit: Part Three

My husband and I spent a couple hours assembling another Lab Kit for the kids.  This round has materials for Precipitates, 2 Grams lab, Instant Snow, Benzoic Acid Blizzard, and Thermoplastics.  Once we finish moles and Stoichiometry, we are going to need some fun labs.

Precipitates

My kids are in the doldrums of moles and Stoichiometry.  Before they can do a Stoichiometry lab, they need to understand precipitates.  The Stoichiometry lab they will do involves making two grams of a precipitate.  Here are three precipitate reactions to try.  Don’t confuse sodium carbonate, Na2CO3 with baking soda, NaHCO3.  My kids are learning how to predict and write the equations, too.  Best of luck!

Solubility Rules

 My Co-op Chemistry class is working on moles and Stoichiometry.  Usually, we do a solubility rules lab, similar to this lab.  Here is a solubility chart.  The kids are going to do the Stoichiometry lab, Can you make 2 grams?  The 2 Grams lab requires kids to determine the formula of the precipitate, which is insoluble.  Ideally, the kids predict the products and use the solubility chart to determine which product is insoluble and the precipitate—or I just tell them.  In any case, I want the kids to do the Solubility Rules lab to see precipitates and use deductive reasoning to determine the rules.  The problem is the best compounds for precipitates are silver nitrate and barium nitrate.  Silver nitrate is expensive.  My kids are going to work through the Precipitation Reactions from TEKS, which has a video lab.  Not ideal, just practical.  Here is the blog post about a solubility lab we did last year.

Calculators in a Caddy

I keep my calculators in a caddy for Co-op classes.  Good Will has a set of TI-15 calculators with a caddy just listed. Here is a similar listing on eBay.   Take a look.

Claim Evidence Reasoning with Far Side Cartoons

 There was a post on social media about using Far Side cartons to instruct Claim-Evidence-Reasoning.  I put the links and sample cartoons into a slideshow with the links.  What a fun idea!  Yes, my kids are doing this!  Take a look.

Trials and Experimental Design

 After yesterday’s fiasco with cola and Mentos, we are doing one more experiment with Coke Zero and Mentos, using six half liter bottles, three warm or 65 degrees F. and three cold at 38 degrees F.  Paul, ten, is comparing the effect of temperature on the volume of the geyser. Paul’s hypothesis was the cold would gush more soda than warm.  Rob said warm would gush more.  We added the null hypothesis: warm and cold soda would gush the same amounts of soda.   Paul and my husband, Rob, added Mentos to the warm Coke Zero bottles and averaged the volume remaining.  They repeated the process with three bottles of cold soda.  Paul will write a lab report next week.  My goal is to teach experimental design, hypotheses, controlled and independent variables, a minimum of three trials, and data tables with fun experiments.  Take a look.

Controlled Variables

 Update.  If you use the geyser tube, be careful to close the lever holding the Mentos candies.  If you jar the geyser tube as you walk outside, the Mentos will dislodge, and spew all over the walls, floor, and notebook.  Ask me how I know.

Paul,  ten, is doing several soda and Mentos experiments to learn about experimental design.  Yesterday, he tested 2 L bottles of  Coke and Coke Zero.  Today, he’s testing 2 L Sam’s Cola and Sam’s Diet Cola.  The bottle were left on the counter at an ambient temperature of 65 degrees F.  Today, Paul and I discussed controlled variables and hypotheses.  Note, all of these tests are different experiments.  We should be doing a minimum of three trials.  (We will test six small Coke Zero bottles tomorrow, three refrigerated and three at ambient temperature.). Today, we talked about yesterday’s experiment.  Yesterday, Paul thought the Coke would spew more than Coke Zero.  In fact Coke Zero produced a greater geyser.  I explained that the evidence refuted his hypothesis.  As we work through these experiments, we are discussing format, data tables, metric measures, etc.  Today, Paul wrote a list of controlled variables.  Once he finishes the experiments, he is going to write a formal lab report.  Experimental design is a process.  My goal is to help Paul learn about the components of a lab through experimentation, rather than memorize the parts or steps in the scientific method.

Isolate a Variable

 Paul is going to do the soda and Mentos experiment today; the weather is calling for snow.  Coke and Mentos labs are best performed outside.  I bought several bottles of soda.  Paul is learning how to isolate a variable and controlled variables.  Here is the post from Steve Spangler suggesting different experiments.  Paul and I talked about different factors to test: volume, temperature, brands, sugar or sugar-free.  He asked if the geyser tube fits different size bottles of soda.  Paul put three bottles of soda in the fridge yesterday.  Each change in conditions is a different experiment.  So the lab is about experimental design not geysers of soda.  Geysers of soda spewing all over the deck makes science more fun.

Family Science: Ice Art

 The weather forecast is calling for more snow.  The Chemistry Co-op class is working through moles.  My brain is half-frozen.  Consequently I thought about an ice experiment.  I tried this experiment, Ice Art with Watercolors at Science Camp one summer.  I froze bowls of ice and let the kids sprinkle salt and tempera paints.  I thought the experiment might prove a bit lame.  The kids enjoyed the artsy effect of paint on the ice for over 20 minutes.  If it’s cold enough, freeze several bowls of water outside.  Try different paints.  I use tempera because it’s cheap.  Food coloring or water colors are expensive.  You might try leftover acrylic paint from a paint by number set, too.  

When we did the ice activity, the paints I had were too thick.  I ended up freezing the bowl of water in the freezer because the temperature outside warmed.  Be sure to look at both sides of the ice.  The underside was even cooler than the top.  We used food dye instead.  Paul tested three salts, and took photos.  He’ll do a watercolor background, mount the photos, and frame them for presents.

Things You Never Knew You Needed: Instructional Kits

 Good Will has the Rocks of the World and The Story of Oil.  Both are old-school instructional sets.  In the 1960s-1970s science instruction was largely industrial.  It’s fun to see how science has changed.

Beanium Lab

 My Co-op Chemistry class is working through the Beanium Lab.  Here is the slideshow I made for the lab with sample calculations.  I took a sample of mixed, dry beans, and went through the lab step by step.  When I go over these calculations with the kids, we compare our calculations.  I request the kids to divide the beans into a minimum of five categories.  The kids must weigh and count beans for each category.  There are several versions of Beanium available.  Northern reason we are doing Beanium is to help kids understand that the atomic mass of an element is a weighted average of the relative abundance of each isotope of the element.  I hope the slideshow helps. I just added an analogy of weighted grades.

Family Science: Magnetic Levitation Kit

 The Magnet Levitation Kit I bought from Good Will arrived.  (eBay has other for about $20, too.)  Paul, ten, and my husband, Rob are working through the experiments.  I did not realize the kit had several experiments and projects, along with instructions.  I thought it would be a maglev model.  Rob and Paul wanted to try the kit.  Why not?  Below are a few photos of the first experiment.  This is a nice kit.  Rob will be able to use the kit for the Magnet section in Physics or Physical Science.