In preparing for Middle School Chemistry with our co-op our family we are going through
Matter and Energy: Principles of Matter and Thermodynamics
. This volume has two chapters about chemical reactions and the periodic table so it makes a good transition.
The first chapter is about the Law of Conservation of Matter, and while we just read the chapter I've been inspired by something I found
here. I modified it for homeschoolers, taking out much of the school jargon and requirements, and
posted it here. I hope to try it and blog about it soon.
Meanwhile, the second chapter is "How the Elements Combine." Proust first figured out that chemicals combine by
mass in definite proportions. Dalton realized that some chemicals combine in several but definite proportions, a fact that fit in well with his proposition of matter being made up of atoms. Next Gay-Lussac showed that gases combined in the same proportions by
volume, leading to his law stating that equal volumes of gases have equal numbers of atoms (Avogadro figured out how many.)
This was all well and good, but I was not sure how much they got from this chapter. I did not have the materials the book listed to carry out electrolysis. I did an Internet search and found that some people used pencils with both ends sharpened, making holders from Styrofoam trays or cardboard, all powered with a 9V battery. (See
here and
here.) I wanted to capture the gas as was done in the book so we could test them, so this is what I did:
I filled a measuring cup with water and added a teaspoon of salt. I attached a piece of aluminum foil to one end of two wires with alligator clips. I filled the test tubes with water and placed them over the foil pieces, using the top of the test tube rack to hold them upright. Finally I connected the other end of the wires to each terminal of a 9V battery. As you can see at the top of the test tubes gas began to collect.
My boys knew water was H2O, and that meant 2 molecules of hydrogen and one of oxygen. I explained that electrolysis was "splitting" water with electricity. I posed the question, "How do you know which gas is collecting in which tube?" We went through the chapter again. Proust and Dalton both worked with mass while our experiment was based on volume. We discussed more about Gay-Lussac's law and asked how definite proportions relate to the creation of water with H and O. The wheels started turning and they then knew for certain that the tube with more gas had to be the hydrogen.
I do suggest a lantern battery for this, though, because the 9V ran out when only a fourth of the hydrogen tube was filled. But I am actually a bit glad. I pulled it out of the water, let the water fall into the measuring cup, lit a match and put it into the mouth of the tube. The loud whistle and pop was impressive enough to prove that indeed it was hydrogen.
To go with this we are reading The Wonder Book of Chemistry by Jean-Henri Fabre. It is available at Google Books or The Baldwin Project online, or through Yesterday's Classics in print form. It covers a lot of what Middle School Chemistry does plus a whole lot more, including a little plant biochemistry.
2L bottle with a cap filled with water 
I used the paperclip to attach the straw to the diver by first clipping one side of the straw and then clipping that onto the diver. I then gave the diver some clay boots to weigh it down a little but not have it sink altogether. You can see in the picture that when I put it into the water it bobbed at the top; I just pushed it in a little and put the cap on.
The rest of the chapter we discussed. The illustrations in the text are great, but I wanted to find or rig a container similar to what is pictured in the book with the connected water columns and the piston. They got a basic understanding of the concept but I extended it to remind them that what they gain in strength they have to make up in distance, just like other simple machines. A simulation or demonstration would have gone a long way here.
I thought about getting a set of density blocks for a demonstration but in the end I decided to use computer simulations instead. Both ExploreLearning and Adaptive Curriculum have several great simulations covering density and buoyancy. PhET has one for buoyancy and another for density that are free, as is the Floating Lab.
Yesterday was the dealine to submit results for the Journey North Mystery Classes. Here is what I came up with for the 10 locations. I include links to pages I made as to how these cities fit the final clues given.
The Edgerton Center at the Massachusetts Institute of Technology offers free project-based classes to school groups. This year our entire co-op and another homeschool family took part in the Quizboards program. Kids used a template to create quiz questions at home. The Edgerton staff then gave them the cardboard frame, wires, and paper fasteners so that, with a bit of soldering (the highlight of the class) they created their Quizboards.
The finished board has two alligator clips. One you hold next to the question, the other you touch to your selected answer. If it is correct then the small bulb on the clip lights up.
The final section of Objects in Motion is about angular momentum. We read this section and discussed how points farther from the center move faster than those closer. We also had a spinning chair in the room that they made use of to show how they spin faster with their limbs closer to their bodies.
This is our third year doing this project--an excellent example of projhect-based learning. Using sunlight and cultural clues, you try to locate 10 mystery locations around the globe. It combines science, math, and geography into one fabulous project. This Friday is the first data set so it is not too late to start. Just click the Journey North tag in the right sidebar to see my blog posts from last year.
