January | 2012 | jepedro

This week in class we were again working with our Lego robots. The goal of this weeks lab was to calculate the percent error of how far the robot traveled at 3 different power levels. The first step was to calculate the diameter and then the circumference of the robot’s wheel. My partner and I found that the diameter of the wheel was approximately .05m. Now having the diameter we could calculate the circumference using the formula for circumference which is: c= pi or 3.14 x d. Plugging the diameter into this formula we found that c=.15m. This is the number we plugged into the lab view panel on the computer.

After our robot was all hooked up to the computer we could begin having our robot move at the various power levels. We chose the power levels 25, 50, and 75. What follows is the data we recorded for each:

Test 1: Power= 25
Rotation 1= 325
Rotation 2= 326
# of turns=.9
Distance=.14
Velocity =.14

The distance we calculated=.20

Test 2: Power= 50
Rotation 1= 758
Rotation 2= 761
# of turns=2.11
Distance= .32
Velocity = .32

The distance we calculated=.42

Test 3: Power= 75
Rotation 1= 1183
Rotation 2=1187
# of turns=3.3
Distance=.49
Velocity =.49

The distance we calculated=.59

As I stated at the inception of this entry the main goal of this lab was to calculate the %error between what the computer says occurred and what we calculated the old fashioned way by measuring with a ruler. The formula we were given for % error was:

%error= measured distance – lab view distance / 1/2 (measured distance + lab view distance)

We computed this for each of the 3 power levels we tested and found that:

For Test 1 the % error was 27.03%

Test 2= 19%

Test 3=35.3%

What I got out of this lab was that although we sometimes believe that computers are always 100% correct this is not always the case. Because the robot was only traveling small distances we were able to do the actual calculations and find that although the computer calculations were close they were never identical to the measured distances.

Below is a picture of our robot during this experiment.

Apparently I was living under a rock for the past year or so. The reason I say this is because I had no idea about the nuclear disaster Japan experienced in March of last year. I am proud to say I did make it out of my cozy home under the rock a little bit because I did know about the tsunami that struck there but still, I knew nothing about the nuclear disaster that occurred soon after this. This blog entry aims to simplify what occurred during the Fukushima Daiichi Nuclear Disaster for those of you who are like me and had no clue!

WHERE? At the Fukushima Nuclear Power Plant in Japan.

Above is an aerial view of the plant with 6 numbered reactors.

WHEN? In March of 2011; soon after the Tohuku earthquake and tsunami.

WHAT? The power plant experienced equipment failure resulting in the release of radioactive materials.

WHY? After the earthquake the reactors in use on the plant shutdown. At this point the emergency generators came on. AKA they were still in good shape. But, after the tsunami hit the reactors connection to the power supply was broken and it all went downhill from there. After the connection to power was broken the reactors began to overheat consequently causing the reactors that were in use (1,2,3) to experience complete meltdowns.

At this point the main goal of the workers was to try to cool the malfunctioning reactors. Despite their early efforts a hydrogen explosion occurred. After this explosion the Japanese government became scared that radioactive materials would soon be released. They ordered evacuations around the plant and ordered ordered that an attempt be made in which ocean water would be used to cool down the reactors. This attempt completely ruined the reactors.

As aforementioned due to this nuclear disaster many people in areas around the plant were evacuated from their homes. Reports estimate that there were as many as 160,000 displaced people as a result of these evacuation. Additionally, because of the radioactive material that was released, not only into the air but into the ground and water as well, there is concern that there will be long term consequences. These include concern that the radioactive material will cause cancer and have lasting psychological effects on the individuals exposed to it. Another problem this disaster has caused is with food and water supplies in the area. The supplies have been contaminated and destroyed.

Japan has also received harsh criticism not because this disaster occurred but for their efforts after the fact. Many say that they did not do a sufficient job in communicating what was actually going on to the public. (Maybe that’s why I didn’t know about it??!) Also, it appears as if they were trying to cover things up and make the disaster appear to be not as bad as it actually was. A prime example of this would be how initially they rated the disaster as a 4 on the International Nuclear Event Scale (NES). But, later it was rated a 7 on the scale which is the highest number on the scale.