Activity 1: On Measurement

Last Monday, we discussed about measurements. I think every laboratory class has to allot time for simple discussion regarding measurement. Especially, this is a Physics lab course, so measurement is a part and parcel of every topic. Well, I've learned new things and few techniques which is actually handy for laboratory class. I guess I'll mention my favorites of those. First is that measurement units are products of arbitration, that no measurement is literally exact. It kinda struck me, though. Second, is that all the measurements are based on the judgement of the person, like if you see a reading between 1 and 2 mm., most people  would probably bet that reading is exactly 1.5 mm regardless of many considerable yet small decimal values. And last, the limitations of the device you're using affect your measurement.

Activity 2: Using Calipers

So this is the activity that we will finally apply and get to see what the results would be like... We're going to measure the length of a rice grain. Sounds simple. But personally it's a no. Honestly because, back when I was in high school, I've never touched or seen this:

A Vernier caliper. (image from amazonsupply.com)

and even this:

                                                 A micrometer caliper.  (image from amazonsupply.com)

 So apparently, that was my first time to use laboratory apparatus like these. Although, we did not have enough time to the micrometer for this meeting..  Okay I'm going to tell how our group measured the rice grain. At first, we were warned by our instructor using the Vernier caliper. He said that you must check the measurement readings by holding the caliper upright because a little parallax could cause you a big trouble while measuring. I tried it myself, reading the measurement slightly slanted and it is true! 

Then, we measured the rice grain one by one, piece by piece. It's kind of hard because whenever it's my turn to measure the grain, my thumb and index finger got stuck as well. We set our goal to 50 grains but then our group ended up measuring only 43 grains. One thing I noticed from our results is that all our measurements (in mm.) are relatively close to each other. If I remembered our data right, we only had 2 out of 43 readings containing 6.00+ mm. The rest mostly measured as 7.00 + mm. .Our instructor also shared the results from a research about the average length of rice grain from a high-resolution experiment. He said that those researchers were able to measure at least a thousand grains of rice. Woah, they were so patient!

Overall the two activities, I think, train us to be careful or meticulous about the objects we want to measure.... and be patient, of course. It's hard to measure a grain of rice, especially if you're trying to measure a thousand of them!