No Lab, Just Talk

This week my class and I talked even more.  This time we discussed three other labs and then we talked a little about how to convert between metric units.  These labs were the Tile Lab, the Lever Lab, and the Pendulum Lab.  Now, just to let you know, my group and I only did one of these labs, so I won't be able to put down as much on the topic as I usually would.

The Tile Lab

Before I begin, I have to say that I did do this lab, so I know at least how the procedure went.

For the Tile Lab, we were asked, "Is there a relationship between the area and the mass of the tiles?"  My group and I thought that there was, and that it would be, a linear, direct, and proportional relationship (at least that's what we drew in our predictive graph).  We then set off to work.

To measure the area, we traced the tiles on graph paper and counted the squares inside the shape to find the area.  For the mass,  we measured it on a triple beam balance.  We then recorded the information and graphed it.  According to our graph, we did end up seeing a direct and linear relationship.  Was it proportional though?

This was where our class discussion came in.  We discussed for a while.  For this discussion, we found:

• The relationship would be proportional because we would expect the graph to go through (0,0).  It makes logical sense because, if there is 0 area, there has to be 0 mass because there wouldn't be anything there.  It is also proportional because the graph would go through the origin, fitting our definition of proportional.
• We also realized that our teacher must have cut the tiles into weird and different shapes on purpose to make us see what would happen if the tiles were all different.
• We decided that it was more efficient to count squares to find the area than to do anything else. Although, another idea was brought up where we would divide the tile into smaller shapes, find the area of each shape, and then add them together. We aren't sure if that would be more efficient however, because we didn't try it.
• The five percent rule tells how good the area relates to the mass.
• We are positive that there is a relationship that is direct and linear.
• We concluded that for every square the area increased, the mass would increas by 0.1975 grams.

The Lever Lab

After the Tile Lab, we discussed the lever lab.  We were asked, "Is there a relationship between the mass of the weight and the distance to the fulcrum." Keep in mind that my group did not do this lab, so I'm not sure exactly how the other groups did it.  According to the groups, they did say that their procedure was to balance a weight on a stick.  Depending on the mass of the weight, they would need to move the weight closer or farther to the fulcrum.  During our class discussion, we decided:

• Our clonclusion would be that for every gram of mass, the distance to the fulcrum would decrease by an exponent.
• The graph and data would never hit (0,0) because there would always be some weight on the stick. This would mean that the five percent rule wouldn't apply. 
• The relationship is indirect because when you increase one, the other decreases.
• The relationship is inversely proportional because as one doubles, the other halves.
• When choosing units, you should choose the one that makes the most sense and works the best for you.
• There is no y-intercept or x-intercept in this relationship.
• y and x go on infinitely. 
• The best type of graph for this relationship is a power graph.
• Distance= 1393x^-1
• Distance(inches)=1393(inches times grams)/mass(grams)
• inches times grams= unit of torque

The Pendulum Lab

The last lab we discussed was the pendulum lab.  For this lab, we were asked, "What is the relationship between the mass and the length of a period?" Again, my group and I did not do this lab, but I was told that the groups put a weight on a pendulum and timed how long it took to swing back and forth.  The groups would add mass to the weight and see if it would effect the time.  In the class discussion, we decided:

• For every 500 grams of mass added, the period stays relatively the same.
• The groups time depended on how long they decided a period was.  Some groups thought 10 swings was a period, while another thought 2 swings was.
• The more swings you measure the more accurate your data is?
• There was systematic error when the person clicked the timer to measure the time.
• Scientific notation: 7 E -5 and E= times 10, so 7 times 10^-5 is 0.00007.
• To be more accurate, we could use motion sensors or photo gates.
• The graph is a straight line, so the equation should be about y=17.
• Bowling Ball vs. Tennis Ball: The amount of time for a period wouldn't change.  Their periods would both be the same.
• Periods are the same no matter how big or heavy an object is.  This is because of the acceleration of gravity.  No matter what the object is or where you are one Earth, the pull of gravity is always the same, causing it to fall, swing, or whatever it is doing at the same rate as another object.
• There is no relationship.  If you do something to one, nothing will happen to the other.
• It has a slope of 0.

Converting Between Metric Units

We also talked somewhat about converting between metric units.  We came up with the basic idea of KHDUDCM or King Henry Drinks Unlimited Delicious Chocolate Milk.  However, we know that there are other units that we need to convert to, so there has to be another way.  I think we will talk about it next class.

Reflection

I think that this week I definitely improved in my participation skills.  Our teacher told us to get our ideas out there, and that is exactly what I am trying to do.  I am just trying to get better every week, and I hope that I will be a master of all this by the end of the year.  I still feel like I am understanding the information we have been discussing, and I am beginning to become more comfortable with my fellow students. Until next week!