My name is Shirley, and this is my blog! This blog will be sort of a diary for my freshman physics class with Mr. Battaglia. I've always wanted to try blogging, so this is sort of exciting.
Anyways, now down to the science-y stuff:
We recently did a laborama, and did a really good board discussion*** on the first lab, Circle Lab #1- which, unfortunately, we did not get to, since our group lollygagged a bit. But thankfully my classmates really cover things well, so I think I really got the gist/what I should have gotten from doing the lab.
We determined/discovered a few key things that should be useful in future labs:
- Data- We realized that if our data obviously doesn't make sense, we should use logic to pick the correct regression for the graph. For example, in this specific lab, which asked the relationship between diameter and circumference, one of the groups found that a quadratic equation best fit their data. However, using common sense will easily show that it's a linear relationship, and from there we found an outlier in their data.
- (0,0)- As a class, we decided that we should add this as a data point in our tables- obviously, only in the labs that make sense (if they have a necessary y-intercept, for instance a fixed weight that you're adding to, adding 0,0 would definitely mess up the data.). We shouldn't force the graph to go through the point (that is an option on Excel), but adding it as a point would definitely help.
- Y- intercept- Again, use our previous knowledge. If it should be zero, take a look at your graph and make sure it's not way out there.
- Slope- This should be easy, but I'll just touch on it for a quick review :). Slope is change in y over change in x. (or delta y over delta x). In this lab, it was change in circumference over change in diameter- and we discovered our slope was pi! That obviously comes from 2*pi*r.
- Units for slope- This was a little trickier for me- not sure I quite grasped it- but basically, I think it you are measuring both variables with the same unit, your slope won't have any real unit. Like for this lab- diameter was measured in centimeters, as was circumference. But if you have speed over distance for example, you will most definitely have a unit (unit for speed over unit for distance).
- 5% rule- This is a rule Mr. Battaglia taught us to make sure our data wasn't crazy wacky: You take the y-intercept and divide by your largest y value in your data, then multiply by 100. If it's 5 or less, your data is within the margin of error. If it's too big, someone made an oopsie somewhere. This proves to be a very good checker. In one of our labs, we got 0.52%!
- The overall equation- we solved 2*pi*r! This was very exciting for me (some people found it thoroughly uninteresting. Humph.).
***By the way, for the zeros of people reading my blog that aren't Mr. Battaglia, a board discussion is where we write all of our lab group results on big personal white boards and then stand on the outside of the room and take turns discussing our results and coming to an overall conclusion.
