The $150 Lab

"Don't let the machine fall off the ramp- it costs $150!!!!", Mr. Battlagia told our group this past week. Wow!!! I never thought such a little foot long machine would cost that much! As you can imagine, our group didn't want to pay $150, so we protected that tiny machine. So, what was this highly expensive lab you may ask???? Well, here's a clue- it involved a ramp, some books, a long piece of carbon paper, and a little machine that rolled down the ramp. 

Mr. Battlagia presented us with the question, "How does time affect the position of a cart on a ramp?" To solve the problem, my group immediately started getting all the supplies we needed. Our group was lucky enough where we didn't have to dot the ramp every second with a marker. We got to use carbon paper that was attached to the car. As the car rolled down the ramp, the paper received dots from a needle like object. The more space between the dots, the faster the car was moving. The data we found out was...

Time (sec)      Position (cm)

30.                            14.5

60.                             44

90.                              93

120.                           157

150.                          232

Once we collected our data and made our white board very colorful, the whole class got together for a group discussion.   In the discussion, we first talked about how everyone's data was extremely different. Our data was especially different from everyone else because we got to use the carbon paper. Other groups struggled just to get 5 seconds, but somehow we got 150. My group wasn't very sure how it was possible to get 150 seconds but we figured it had something to do with the carbon paper being more efficient than dotting the ramp with a marker. The class also discussed the graph. We ended up with a polynomial graph. Our next topic was about the equation for the graph. My groups equation was: 

P= .0084t^2 + .3124t-3.3. 

Of course none of the groups had the same equation because we didn't have the same data, but we determined the units for each section of the equation. •The .0084t^2 represents acceleration because of the cm/t^2. 

• the .3124t represents the speed. Cm/t

• the -3.3 was the starting point. Our group didn't know why it was negative because we couldn't have started at a negative number, but we thought it had to do with human error. 

Well, that wraps up another blog entry! I guess tomorrow we are doing computer programming. I never have programmed a computer before in my life, so this should be interesting! 

                        ¡Adiós!

Motion Maps

In physics class we talked about motion maps. At first, they were a little complicated, but as soon as I started doing more examples, I quickly got the hang of it!

We first learned about motion maps through doing a lab with motion detectors. The lab gave us the position vs. time part, and we had to act out the movement in front of the sensor. After we got the trend on the computer, we drew

the motion maps. The packet started off fairly easy, but then proceeded to get more challenging as I got to the end of the packet. My group was confused mostly when the lines started to go all over the place on the graph. We didn't know how to act out the motion. After getting help from Mr. Battlagia and other groups we were able to work through it line by line! 

Here are some motion maps-

In this example the object is moving in a positive direction at a constant speed. The arrows are going right because the object is moving in a positive direction. If the object was moving in a negative direction, then the arrows would be moving to the left. We established in class that the dots represented the object and the arrows represent velocity. Velocity is the speed and direction in which an object is going. If the object was traveling at a very fast speed, then the arrow would be longer than if the object was moving at a slower speed. 

Here's another motion map-

This is a more complicated motion map. The object moved to the right and then stops and then moves to the left. The orange arrows were moving at a faster velocity than the yellow because they have a longer arrow. The yellow arrows are moving at a slower velocity. Their arrows are shorter. Dots stacked on top of each other represent a stopped object.

Another example-   

In this example both objects are moving at the same velocity (yellow and the black arrows). The only difference is the yellow arrow started farther up than the black arrow. 

Well, that pretty much wraps it up for 

motion maps. In my upcoming blogs I'll be discussing velocity vs. time and position vs. time graphs! 

The Buggy Lab

"One, two, three, four, five, mark" is what I kept on repeating to my lab partners last Thursday. Yep, you guessed it, we were doing the Buggy Lab! Before I tell you what happened in this lab, here are two things you need to know-

•Reference Point-a chosen/ set point, which determines your position. 

•Position- where you are compared to the set point. 

Now I can begin!

With the help of two other partners- Brad and Julia, we were on a mission to answer the question, How does the time a car travels affect its position? We quickly found a small spot, but quickly realized that we would need a much bigger space because of how fast the blue buggy moved. So, we moved outside to the hallway. Our team decided on our positions in the lab. I would be the timekeeper, who would count with a stopwatch, and count up to 20. We marked our reference point and started the buggy. Every multiple of 5, Julia would mark with a sticky note, where the buggy was at that time. When I finished counting up to 20, Brad counted using cm, how far each sticky note was away from our reference point. He determined each sticky note's position. 

Here's what our results were.

Time(sec)     Position(cm)

5.                          193

10                          375.5

15.                         566.5

20.                         762.5

Mr. Battlagia then juiced up our experiment a little more. We had to move our reference point 50 cm forward, and start there with our buggy. But we had to include the length of the previous reference point. I know it sounds really complicated, but all we did was start the buggy 50 cm. forward. Not that bad!

Here were our results:

Time(sec).           Position(cm)

5                               254

10.                             439

15.                                634

20.                                830

I was actually surprised by our results for the data table above. I thought that the position would only increase 50 cm. from the first data table's position. However, that was not the case.

After completing the experiment, our group headed back to the classroom, where we started right away creating our boards for discussion. This is what our board looked like-

So, to answer the question of the experiment, yes time does affect a car's position. For every second our buggy traveled, the buggy traveled about 30 cm. 

The blue is our first part of the experiment. The green is the "juiced up" part if the experiment, where we moved our starting point with the car up 50 cm. We had our board discussion soon after. Many great points were brought up such as, "why isn't the y intercept 0 in the blue one if we started at 0?" Well, our group made a simple mistake with not putting in 0,0 in as a point for our equation. We are also not robots, so nothing can be measured perfectly.

Here are more points we talked about-

• y intercept is the starting point of the buggy

• distance, is not the same as position.

• cannot have negative distance

• faster speed = steeper slope. 

•linear graphs

 

Our board discussions are improving, however I still feel like more people should talk, and ask questions more! I feel like I could improve on asking more questions. 

In order to succeed in this lab, we definitely had to work well with our partners. I believe that my group did a great job together! We all had specific roles, and we used our time efficiently. I'm really looking forward to the next time we get to work with buggys again!!!!

More skills we've been learning

In physics, we've been learning even more skills! We first learned converting between metric units. It sounds complicated, but it's actually really easy after you understand how to do it. When converting, I always reference this chart-

KHD(base)dcm. 

K: kilo

H:hecto

D:deca

d:deci

c:centi

m:mili

Your base unit could be meters, grams, or liters. The largest number is on the far left. Smallest number on the far right. I remember the saying as King Henry Died (base) drinking chocolate milk. What makes this really easy is each unit is based on a power of 10. You move the decimal point either to the left or right. 

Here are some example problems-

1.) 6 l.=_ ml.

             .000006mm

2.) 50mg=_ kg

            .00005 Kg

3.) 25 Km=_cm

            2500000 cm

We also learned scientific notation- 

1. 9,000,000=9•10^6 

2. 9,260,000= 9.26•10^6

3. .000006=6•10^-6

Dimensional analysis-

You use dimensional analysis when you have two units that do not have the same base, such as meters, grams, and liters.

An example-

1. 30 miles

  __________    = _ m/s.

       hr.

  

30miles.    1 hr.        1.609 km.    1000 m

______   • ______   • _______.  •_______

1 hr.        3600 s.       1 mile.          1 km

Answer- 13.41m/s

Dimensional analysis is the toughest subject that we learned so far. After doing a ton of practice problems, I think that I have it down pat. 

 

I think sooner than later, we are coming to an end with learning science skills, and will finally start doing physics soon! Very excited!

Difference Between Graph Trends

In Physics I've learned a ton about graph trends. Our discussions were so detailed, I would always walk out at the end of class with my head hurting. But, confusion was leaving my brain, so I guess that's a good thing! 

   Here are the differences between the graph trends I learned-

• direct- when the x increases, y increases OR when x decreases, y decreases.

•direct proportional- constant rate of change between x and y. The graph is linear, with zero as the y intercept. When x doubles/ triples/ etc, then y doubles/triples/etc. 

•indirect- not direct, so when one variable increases, the other decreases. 

•inverse proportional- when x is doubled/ tripled/ etc., y is halved/ thirded/ exc. There is no y- intercept. The graph for this trend typically looks like a hyperbola. 

•inverse- as x increases, y decreases OR as x decreases, y increases. 

To make a trend proportional, the x and y values have to be increasing/ decreasing equally, at the same value. 

Can't wait to learn more!!

How the experiments are going so far in physics

So far I'm having a good time in physics doing experiments! Our group had the toughest time doing the dowel lab. Measuring the length of the dowel and finding the mass took a longer time than some of the other experiments. The easiest experiment were Circle labs 1 and 2. Our group found it much easier to measure the radius and diameter of the circles. At the end of our labs I feel like the group sharing in the circle is helping me understand other peoples' viewpoints when our groups don't share the same conclusion. I'm excited for future labs!