Quarter+3

toc =Quarter 3=

Gathering data through all the senses
In many of our labs, we simply collect quantitative data. What was the decrease in mass? How long did the reaction take? By how many degrees did the temperature increase? Typically, this data is collected visually by simply reading measuring tools. By analyzing such quantitative data, we can draw more solid conclusions backed by hard evidence. If you look at the video of the precipitate lab that we performed in Quarter 2, you'll see that even when we collected qualitative data, it was predominantly through visual means (in this case, we noted a change in color that was indicative of a chemical reaction taking place). On some occasions, we also employed our sense of smell to gather data, such as the times when we used acids or sulfur. However, this quarter, we used a sense that generally we avoid using in Chemistry as a safety precaution--using this sense with acids and bases would be disastrous--and that sense is: touch.

This quarter, we learned about exothermic and endothermic reactions. In lesson 1 of this unit, we performed[| simple experiments] and were asked to determine whether the reaction was an exothermic or an endothermic one. As exothermic reactions release heat and endothermic reactions absorb heat, the graduated cylinder would become warm if it was exothermic and would feel colder if it was endothermic. By feeling the change in temperature with our hands, we were able to determine the reaction type. Later in the unit, when we performed experiments with [|coffee cup calorimeters] and burning different types of food, it was confirmed through data that exothermic reactions would result in higher temperatures and endothermic reactions would lower temperatures.

[click on the links to see videos of the experiments!]

Thinking and communicating with clarity and precision
Writing a good lab report is a skill that teachers have stressed all throughout middle and high school. Surprisingly, though, the lab report we wrote on the lab comparing methanol and ethanol as fuel sources was actually the first one I'd written all year. We never write lab reports in AP Biology simply because it's not a skill that is tested on the exam, and it was the first one we'd done in Chemistry, so when it was time to write the lab report, my skills were a bit rusty. This was particularly evident in my conclusion and evaluation. I made very general statements about our conclusions and stated the flaws in our procedure and they ways they would impact the results, but I wasn't specific about what changes I would make to improve it. When it was time to write the lab report on the lab regarding rates of reactions, I was sure to be more clear about this. I pointed out sources of error in our procedure and described the ways we failed to control certain variables, and suggested ways to improve the accuracy of our procedure if it were to be performed again. I made a conscious effort to improve on the clarity and precision of my writing the second time around and to learn from my previous mistakes. First lab: Second lab: