## Friday, November 6, 2009

### Percent Composition

Today students learned how to calculate percent composition based on formulas using molar mass and based on weights from word-based math problems. Once they got the hang of it, it was time for Science Friday festivities.

Students each had a piece of gum - one they brought in or one from me. They all brought in chewing gum (even though the board said bubble gum) and I brought in bubblegum, so there was some trading. Students observed the gum by weighing it, drawing it, and smelling it.

Next they chewed the gum for ten minutes. While they were waiting we watched How Its Made on bubblegum which is linked to the side if you want to see it (and then another episode about potato chips because we had time). We also had a little fun blowing bubbles. Ethan could blow the biggest bubbles.
After ten minutes, students did more observations and re-weighed the gum. The gum weighed less... why? Because the sugar dissolved and was lost. Using this weight difference, students determined the percent composition of sugar in the gum they chewed. We worked on making a data chart to make some comparisons and we will finish this on Friday.