During the past 2 weeks of class,
we did several experiments to get an idea of what we are in store for this year
in chemistry.
One experiment we did that I liked a
lot were when we tested the physical and chemical change in matter. I liked this experiment because it was very
hands-on, which I always like in an experiment.
The main ideas in these experiments were to realize that not everything
is a physical change, based on what we can plainly see. Another activity we did in class, that had the
same idea as the previous activity, was when we recorded positive/negative/zero
change and physical or chemical changes with the steel wool, precipitates, ice
and water, alka seltzer, and the dissolving sugar. We concluded that, most of the time, there
was no change among the testers. However,
although there was no change, mass wise, there were a lot of changes between the
physical and chemical aspects. For example,
with the steel wool, when we weighed it in the beginning, its volume was
smaller than it was after we pulled it apart; the mass didn't change throughout
the experiment. So, even though its
volume changed, its mass wasn't, and it was a physical change. Another experiment we ran in this activity
was when we combined two liquids to form a new substance. In the beginning, one of the liquids was
clear, and the other was pink. Initially,
I thought that after we would combine the two, the new substance would be an
even lighter pink. However, after we actually
mixed them, it turned thick and turned a dark, blood-red color. This contradicted my thoughts and made me
think twice about what could happen in the future. With
this experiment too, when we measured the two separate liquids in the
beginning, the mass didn't change after we combined them. Instead, the volume increased. This experiment was a chemical change as
well, although the color of the new substance was different. It was a chemical change because it made a
new substance.
In conclusion, after we ran all these
experiments, I understood that there can be a physical or chemical change even
though there isn't necessarily a change in mass or volume. Throughout the past few weeks, I didn't really
have any particular questions; I understood fairly well what I was doing in
every task. I think my participation in
the learning process was good. I
participated often in class, as well as when we were in groups running the
experiments. I think I need to work more
on going the extra mile, as far as getting the answers I need to the questions I
do ask myself (when I think of questions).
Video of my favorite part of the experiment we ran (burning the magnesium ribbon)
