Week 3

Chemistry was very intriguing this week. We learned some new concepts and we also did some labs.
On Monday, we were informed about the difference between precision and accuracy and how we should record data. Precision was how certain a measurement was limited on the measuring tool that you use. Accuracy differs in the fact that its the correctness of the measurment limited by the observer. Also, your answer cannot be more precise than your least precise measure. So if, for example, you had the measurements 2.2 , 2.6, and 4.5 and had to mulitply them together to get the volume, you couldn't go past one digit to the right of the decimal place. We were also informed about when zero is a significant digit in your measurement. Its not siginificant if its a place holder like this : .3600, but it is important it its at the end of a decimal like this : .000 It is also important to include the zero if its in what we call a "zero sandwich" like this: .303
On Tuesday, we learned a new phsyical property of matter besides mass and volume which is...density! Density is basically how the matter is distributed in a certain amount of space. It can be expressed in multiple ways such as pictures, graphs, algebraicly and linguisticly. Examples of these ways are shown below:

 

That day, we did a lab to find out the density of water. We by measuring the mass of the measuring tube and the mass of the liquid in the measuring tube and subtracting the measuring tube from it. We found out that the density of water was .98 g/mL. But, on Wednesday, we found out differently.

Wednesday, we did a lab to figure out the densities of different liquids: water, Coke, Diet Coke, Sprite, Fruit Punch, Dr. Pepper, Apple Juice, and oil. We figured out the following densities of each one and ranked them in order of least dense to most dense.

After we figured this out, on Thursday we realized from google that the actually density of water is 1.000 g/mL so there was some room for human error here. The reason why all of these liquids besides oil were so close to the density of water was because all of them are made up of mostly water. Since oil is a lot less dense than water is, it rises and does not mix with water. It floated on top of the water when we tried to mix them together.

Overall, this week I got to experience lots of new things about chemistry that I really didn't know before.