Tag Archives: results

Group One’s Data: Radiation on Vassar’s Campus

For our research project, we attempted to measure the counts of radiation in academic buildings around campus using a Geiger Müller (GM) tube attached to a LabQuest 2. We were also interested in seeing if the radiation levels observed correlated with the ages of the buildings tested. This is an important type of testing to do, as over-exposure to radiation, especially \gamma particles, which are high energy photons without mass, can lead to negative results. These can include radiation poisoning, as well as cancer and other genetic mutations. To conduct our research, we walked around each of the buildings at a steady pace for 5 minutes, moving the GM tube from side to side. When there was an indication of possible radiation contamination, the tube was focused on that area to determine if there was a higher radiation count.  For example, there are areas in Olmstead that have radiation warnings on the door, and we stopped and waved the Geiger tube there for a considerable amount of time to test for any radiation contamination that may have been leaking through.


Figure 1. The apparatus used for recording radiation. The GM tube is located on the right. It is a gas filled detector, which functions using a low-pressured inert gas to amplify the signal of any radiation entering the tube. Radiation passes through the gas in the device and the molecules in that gas are ionized, leaving positive and negative ions in the chamber. These ions move toward separate charged sides (the anode and cathode), creating a current which is then sent through the wire to the LabQuest 2 Device to be measured and recorded. Each \alpha, \beta, or \gamma particle entering the tube is measured as one “count” of radiation.

Average (Counts/0.1 Min)

Max (Counts/0.1 Min)






Blodgett Hall




Chicago Hall












Mudd Chemistry




Old Observatory












Rocky Hall




Sanders English




Skinner Hall




Swift Hall







Figure 2. Table of Average and Maximum radiation counts as compared with the age of the building. As read from left to right, the columns are labeled as (1) the buildings tested, with “Background” representing the data we collected between buildings to determine an average radiation level, (2) the average count of radiation observed in each building (per 0.1 of a minute over the course of 5 minutes), and (3) the highest amount of radiation observed in each building, and the age of the buildings that we observed. We initially hoped to be able to distinguish \alpha, \beta, and \gamma radiation from each other, but upon further review, we determined the only types of radiation we were likely to detect were \gamma and high energy \beta. This is because these travel further from their source than \alpha, and are generally emitted by the same type of material.

Figure 3. The average radiation counts compared with the age of the buildings. A trend line has been plotted to show the direction of correlation.


Figure 4. The maximum radiation counts compared with the age of the buildings tested. A trend line has been plotted to show the direction of correlation.


We plotted the above data observed in two graphs (Figures 3 & 4).  Figure 3 shows the average radiation levels by the year that the building was built, while figure 4 shows the maximum radiation level observed by the year the building was built.  As you can see, there is little to no association between the variables in either figure (figure 3: r=0.275, r²=0.076; figure 3: r=0.228, r²=0.052, where the “r” value indicates the closeness of correlation of the data, and the r² value indicates the percent of data that fits within that correlation).

The literature provided by Vernier, the makers of M tube and the LabQuest 2 device, states that expected background radiation levels should be between between 0-2.5 counts of radiation/0.1 min. Our average background radiation testing was within this range (avg=1.32 counts/0.1 min, max=3 counts/0.1 min). All of the average readings from buildings were also within this range (the highest average being taken in Skinner Hall: 2.44). With this information, we can conclude that Vassar campus is safe in terms of radiation levels.


Power Consumption of Flash Drives

Historical Introduction to Flash Drive Price Versus Memory Capacity

Flash drive manufacturers typically advertise their products based on memory capacity, not on power consumption efficiency. One might believe that the two necessarily go hand in hand, with newer memory storage devices making considerable gains in both domains every year.

This is certainly the case with memory capacity. $200 could buy you 8 MB of memory in 2000 (year that USB 2.0 flash drives were first introduced to the public), as opposed to 2GB of memory in 2005, and 128 GB of memory in 2010.  Today, the average-sized 4 GB flash drive sells for around $10. Perhaps these increases in memory capacity reflect changes in everyday flash drive use – particularly in the domains of computer maintenance, law enforcement, business, and entertainment, where 4 GB of memory represents optimal balance between cost and desired memory capacity.

However, this does not imply that the power consumption efficiency of flash drives has seen similar gains. Our investigation attempted to establish whether or not larger drives are associated with smaller power consumptions.

Source: www.ehow.com

Results and Conclusions

The graphs in figures 1-3 show the power consumption of the laptop at rest and of the laptop with the flash drive when it is plugged in, as it opens files, and as it is ejected. Tables 1-3 summarize the data (in a previous blog post).

The data does not point to there being a significant difference among the flash drives and the amount of power they consume. Though we believed that flash drives with greater capacity would be more efficient and would consume less power than would smaller ones, especially older ones like the 256 MB, we did not observe a trend in our experiment. The differences that we did observe may be due to normal fluctuations in power consumption of each flash drive and may not be statistically significant. Some background tests in which a file was opened from the same flash drive more than once show that the power consumption reading on the watts up? PRO fluctuates and is not the same each time. It is clear from the data that a computer into which a flash drive has been plugged in consumes more power overall than a computer that has nothing running on it (figure 1). Ejection of a flash drive consumes about the same amount of power regardless of the size of the flash drive, though the 2 GB drive consumed the most power (+7.6 W), and the 2 GB micro flash drive consumed the least (+5.8 W). Whether this is a real trend, however, is uncertain because it was not observed when opening documents from flash drives.

In order to check whether the power consumption recorded when opening files is due to the flash drive or the computer, the same file was also opened from the computer. The data are inconsistent, however, and it is difficult to tell which device is consuming power, or whether there is a trend among different flash drive sizes. Power consumption was greater when opening files from the computer for only some of the files; for others, it was greater when opening them from a flash drive. This suggests that there is no difference among flash drives, and also that we cannot tell which device is consuming power, a confounding variable that must be eliminated in future experiments.

Overall, power consumption increases when a flash drive is plugged into a laptop, but it is unclear whether larger-capacity flash drives consume more or less power, whether they are merely plugged in or opening files. Future experiments should focus on a more rigorous statistical treatment of data, more of which should be collected using many different types of flash drives. Each type of flash drive should be tested multiple times (preferably three or more) and its power consumption should be recorded. Standard deviations should be determined, which can help eliminate or, at the least, pinpoint some of the uncertainties regarding fluctuations in power readings. It would also be interesting to test particular sizes of flash drives and determine if there is a difference in power consumption among different brands.

Power Consumption of Flash Drives


A laptop was plugged into the watts up? PRO and a baseline reading of its power consumption when it is turned off was taken (0 W). The laptop was then turned on and its power consumption was taken again (12.9 W). With no other programs running, a flash drive was inserted into a USB 2.0 port and a reading was taken of the total power consumption after equilibration. One document or video was opened from the flash drive and the maximum power reading was recorded. The same document or video was then opened directly from the laptop and the power reading was recorded again for comparison. A fourth reading of power consumption was taken when the flash drive was ejected from the laptop. This was done using flash drives of 256 MB, 2 GB (two separate flash drives; one is a micro), and 4 GB capacity.


Table 1 summarizes the change in power consumption when a flash drive was plugged into the laptop, when a document or video was opened, and when the flash drive was ejected. Tables 2 and 3 provide more detailed data of the experiments.

Click for full-size image.