Secular Science Resources for Homeschoolers

Honors Chemistry 09 – Percent Composition

Modern Chemistry Chapter 7, Chemical Formulas and Chemical Compounds was fairly boring, the first half of the chapter was all about chemical names which really put me to sleep. I’m not about to memorize that so I’m not asking my students to either.  The last part of the chapter was about molar mass and percent composition, some of which we’d already covered earlier this semester.  I did give the students a worksheet about naming covalent compounds that I got from Covalent Bonding Interactive Graphic Organizers for the Chemistry Notebook or Lapbook by Bond with James ( The worksheet had half a page explaining naming rules and then half a page where the students had to name the compound or write out the formula.  One of the students did find one typo on that page, the answer key had a different compound than the question sheet.

img_5115The lab for this class, Chapter 7 Percent Composition Lab,  was taken from Ian Guch’s 24 Lessons that Rocked the World.  I really liked this lab, it was fairly straight forward, measure the mass of your container, the mass of container + epson salts, heat epson salts then find mass of what’s left.   Heating the epson salts drives out the water and the change in mass is very significant, so its the not typical small change that you might miss if you’re not careful.  The visible change is also very big and got lots of suprised ‘Wow!’s from the students.  I hadn’t done this lab before so I hadn’t known what to expect either.  One of the students wondered out loud what it would like under the microscope, so I pulled it out and we took some pictures. The photo on the left with the large crystals is hydrated magnesium sulfate (epsom salts before heating), and the photo on the right is anhydrous magnesium sulfate (epsom salts after heating).  The microscope was on the same magnification for both images so you can see the change was pretty drastic.

The lab handout steps the students through the process of calculating the percent composition of water for the epsom salts and then finding the chemical formula.  The last page of the lab includes a worksheet with additional practice in calculating percent composition which I assigned as homework.

This is a great lab for homeschoolers since all you need is epson salts, which you can buy at a grocery store, a scale (and a kitchen scale would probably work since the mass change is so large) and a heat source.  We didn’t get exactly the right numerical answer for the lab, our numbers were all a little low but the students quickly realized that meant they probably didn’t heat the salts long enough so there was still some water left in the cruicible.  We left the lids on the cruicibles while heating, so we didn’t watch the reaction and just heated the 10 minutes stated in the lab handout.  I would like to try this again with the lids off so we could tell when the reaction is done and see if we get better numbers.  The only safety concern with this lab is the heat source.

Tyler DeWitt has a nice set of videos on how to calculate percent composition.

Intro Chem 08 – Periodic Table

This class was a slightly simpler version of the high school class.  We started out watching Crash Course Chemistry on the Periodic Table. I stopped it  a few times and we discussed the different groups and I drew electrons in the different shells for some of the groups.

Then we did a quick run through of the Coloring the Periodic Table Families slideshow that can be found on  And it looks like she already updated that slideshow, I really need to go check her website before class to get the latest stuff!  I did not have the kids color as we went through the slideshow.  When we were done with the slideshow I taped a copy of a periodic table to my whiteboard and we all colored in the different families together and made a legend.  img_5111

I also gave out this really cool periodic table with pictures for each element showing what the element is used for, and had them tape that in the back of their book for easy reference. The website,, where I found this has quite a few nice printables, including element cards.img_5112

The last thing we did was a worksheet called Periodic Table Notes: Determining # of shells and valence electrons from (again the link goes to an updated version of the file I used).  Just like the high school class this made the students take a close look at the periodic table, looking up elements and finding their period, # of shells, their group number and # of valence electrons.

Great apps for playing around with atoms and elements include the NOVA Elements app where you can add the correct number of protons and electrons to make a particular element and of course the Elements app by TouchPress is beautiful.

Honors Chemistry 08 – Ionic vs Covalent

We ran out of time last week with one activity left, so we started this week’s class labeling a periodic table with arrows showing trends in ionization energies, atomic radius, electronegativity, etc. This activity was from the Atoms and Chemistry Interactive Notebook Unit Bundle  by Stephanie Elkowitz.

fullsizerender-6Then we jumped into another lab from 24 Lessons That Rocked the World by Ian Guch.  In this lab I put 5 different substance in centrifuge tubes marked 1 through 5.  The lab only calls for four unknowns but I included distilled water as a fifth unknown.  Two of the substances were ionic (rock salt and sodium acetate) and the other two powders, coconut sugar and agar were the covalent samples.  We talked a bit about the differences in ionic and covalent compounds and what tests we could perform to figure this out.  Covalent compounds tend to have a lower melting point so students placed small samples of the unknowns in crucibles and placed them over the butane burners.

Coconut sugar beginning to melt

If the substance melted quickly then they knew it had a low melting point.   Some never melted, even after several minutes, indicating a high melting point, and some just turned into a black powder.

sodium acetate 

Another test is to look at the material under a microscope (sodium acetate to the left) to determine if it has a crystalline structure, which is more commonly found in ionic compounds.  And finally the students dissolved some of the substances in distilled water and checked its conductivity with a multimeter.  Ionic compounds are more likely to dissolve in water and the resistance was measured with a multimeter.  If the resistance dropped  (increased conductivity) significantly then the substance might be ionic.

Any one of these tests alone is not really enough to conclude whether something is ionic or covalent so the students had to look at all their test results before making a conclusion.

At the end of class I showed  the following two youtube videos, Dogs Teaching Chemistry – Chemical Bonds by snuggliepuppy and chemical party (this one just cracks me up).

I had asked the students to watch some of the videos below before coming to class.

or if they prefer Tyler DeWitt



Intro Chem 07 – Elements

Today I started class with a slideshow, Elements, Compounds and Mixtures from by Liz LaRosa.  I just went there and it looks like she’s updated the slideshow, I used the old one posted OLD PPT.  Its just a simple set of slides explaining the difference between elements, compounds and mixtures and it has a number of slides with just one picture (like sand) and the students have to guess whether its an element, compound or mixture.

img_4936After the slideshow, the students did the Elements, Compounds and Mixtures cut and paste activity from the same website.  I thought this was a nice activity to reinforce the slideshow and made them look at the diagrams of molecules and interpret what they represent.

When they were finished with that I gave them an Adopt-an-Element handout, which I found by following links from to  For this activity the kids pick one element and have to fill out a worksheet on that element.  They are asked for the symbol, atomic number, number of protons, number of neutrons, melting point, etc.  This was a good activity because the students had to look up their elements in a periodic table, dig out chemistry books for some additional information, or use the Elements app, or the deck of element cards.   51qefhedkul-_sx462_bo1204203200_We didn’t quite get to the advertising slogan and I told them they could do that at home because we wanted time to play bingo.  Element bingo cards can be found on the Jefferson Lab website.  I randomly pulled out cards from my element deck and only gave them the real name, like Carbon and they had to guess the symbol (C) to figure out if they had it on their card.  Carbon is pretty easy but elements like Potassium (K) are a bit more challenging.  I also read out some of the interesting notes on the back of each card. We played this til almost everyone had a bingo.


Honors Chemistry 07 – Periodic Table

No lab for this class, it was more of an interactive notebook day.  The Modern Chemistry curriculum comes with some labs (online) and they have one, The Mendeleev Lab of 1869, where you give the students some elements with data like density, reactivity with water, softness, conductivity, etc. img_4826 Most of the elements are labeled by name, but some are labeled unknown and the students have to figure out what they are by constructing a periodic table with the known cards and figure out where the unknowns fit in.  The filling in of the cards took up more time than I hoped so we didn’t get to all three activities that I had planned but I think having to lay out the cards  into a periodic table and really look at the properties of each element to place their unknowns was useful.  All three groups identified their elements correctly.

Then we moved on to coloring the periodic table, and this activity, Chapter 9: Periodic Table is from Science Interactive Notebooks: All About Atoms by Stephanie Elkowitz, which I purchased from  Again, its mainly an exercise to get students to really look at the periodic table and become familiar with it.img_4828

Before class I recommended students watch these videos:

I keep showing this video to my students hoping one of them will try to memorize it.

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