Apologia Physical Science Lab – Module 4

Welcome back to Module 4 and The Wonder of Water.

Due to lack of test tubes, we skipped Experiment 4.1 The Chemical Composition of Water.

….and, since we are being honest, we don’t have pictures to all the labs. Somewhere along the line I put the camera down and didn’t pick it back up until the next lab. OOPS! And that would include Experiment 4.2 Water’s Polarity.

But, anyway on with Experiment 4.3 Solvents and Solutes

In this experiment we will look at what makes a solution.

First, five glasses…. four with warm water, one with Canola Oil

The first glass 1/2 tsp sugar is added, second 1/2 tsp canola oil, third 1/2 tsp salt, fourth 1/2 tsp olive oil and into the fifth a little olive oil.

Results? The substances made up of polar molecules (i.e. the first 3 items) dissolved in the water. Since olive and canola oil are made of nonpolar molecules the water cannot dissolve them.

Well….this is kinda embarrassing. Due to operator error (mine) there are no pictures of Experiment 4.4 Comparing Solid Water to Solid Butter.

Moving onto Experiment 4.5 Water’s Cohesion

After filling the bowl with water, tear off a square of toilet paper. Set a paper clip in the middle of the toilet paper. While carefully lifting the toilet paper by the corners, gently lay it down on the water. Observe.

Once the toilet paper gets completely soaked, it should fall to the bottom of the bowl, but the paper clip should continue floating. Once the paper clip is floating freely, add a few drops of soap to the water. Observe.

Prior to adding the dish soap, you are witnessing cohesion. Once the dish soap is added, the molecules in the dish soap force the bonds of the water molecules apart. This phenomenon is called surface tension.

Join us next time for Module 5 The Hydrosphere. I promise to keep my camera handy!