Blog Post #3

This week in SG Chem1 the main ideas we looked at were mass, volume, and density. On Monday, we measured an amount of water in a cubic container and a graduated cylinder.

For measurements on the cubic container we used cubic centimeters and we used milliliters for the graduated cylinder. We made a chart and it became apparent that milliliters are equal to cubic centimeters. Our chart is pictured below.

Milliliters and cubic centimeters are both used to measure volume. Volume is the amount of space that an object occupies. When using a graduated cylinder to measure volume, you can often use uncertainty to express that the measurement could be greater or less. If you use uncertainty depends on the graduated cylinder you're using.
Mass is the measure of the amount of atoms in an object. To measure this we used grams. We used a scale to measure the mass of five rods of steel, acrylic, and aluminum. We also measured their volumes. Then we put these measurements into a graph to compare the volume to mass using LoggerPro. We looked for how much mass per volume there was. That's the density of an object. This is our graph:

As you can see, g/mL, or the density, is written for each line. This is the slope of each line, rise over run. The densities for each material differ greatly. In class, we went over the densities. Our table's information turned out to be outliers, but the steel had the largest density, and the acrylic had the least, according to the class. The graph is below. We're table 6.

On Friday, we went over problems from a worksheet in class. One problem we went over said something like this: Object E is the same volume as Object F. The particles in Object E are larger and therefore have more mass, but are uniformly distributed throughout the object. Compare their densities. 

After reading this problem, we worked out what we thought our answers were on whiteboards, then had a board meeting. My group's first answer was that Object E and Object F had the same density, because they had the same amount of particles per unit of volume. However, then we realized that, since the particles in Object E were bigger, the object literally had more mass per unit of volume, which would alter the density. 

Since some of the class refused to admit that Object E had more mass, the problem went unsolved, but I believe that our answer is correct based on what we know about density and what it is.

The main ideas this week connect because they're all used to measure. To measure the mass of something is to measure the amount of particles it has, to measure volume is to measure the amount of space an object takes up, and density is the measurement of how much mass per volume there is in an object. Some important details to these main ideas include units of measurement, such as grams (mass), cubic centimeters (volume), and milliliters (volume), and knowing how to use a scale, knowing how measure using a graduated cylinder and knowing what uncertainty is. 

I don't have many questions about what we learned this week, but one that I do have is: did Object E have a greater density than Object F? It would be great if we went over that again.

In the future in these topics I think I need to work on measuring more carefully, so we don't have ridiculous outliers like we did this week.