User:DHafner
From MariachiWiki
I uploaded the file, I thought I made it smaller, but I guess I didn't. It is a picture of Devils Tower in Wyoming. Devils Tower is a volcanic stock, or magma that never made it to the surface and cooled. Over time the less resistant surrounding bedrock and sediments have eroded away. I am in the picture with the black shirt on, just below the trees, to give you an idea of how big this actually is.
Hello, my name is Dan Hafner and I am an Earth Science and Science 9 teacher at Riverhead High School. This is my fourth year, third full year teaching, the first year I came in for the fourth quarter. I also coach middle school soccer and lacrosse. I earned my undergraduate degree in geology and education from Buffalo State College. I originally went to Buffalo State to play hockey, which I did for a few years, but this ultimately is what got me interested in teaching. I started teaching younger kids how to skate and play hockey in my spare time, which I enjoyed so much that I knew I wanted to teach. I am now half way done with the MALS graduate program at Stony Brook, which must include 12 credit hours of my initial content certificate, or any related science course and I am also including the classes needed to get my coaching certificate. I am really interested in the study of cosmic rays because of the idea that they are traveling at nearly the speed of light, throughout our solar system, from distant parts of our galaxy and interacting with our planet.Cosmic Rays I still play hockey once in a while and I am an Islanders fan. I am also a big Yankees and Jets fan.
NOVA I was searching this site for information on lightning for my ninth grade class and I came across this video about the study of lightning. They suggest that a possible cause of lightning is cosmic rays. They suggest that the energy from the cosmic rays gives the "jump start" needed for the big discharge of electricity. Just click on watch the segment, its a short nine minute video.
Since I really enjoy meteorology, especially storms, snow storms to be specific here is a neat site. NOAA
efficiency data
Media:Efficiency data.xls 9-16-07
I felt that the best voltage to run the detector at would be between 5.6 and 5.7 volts. There seems to be the best percentage of coincidence at these voltages, as well as a a lower difference in the number of hits between each of the detectors individually.9-17-07
Possible Experiment 9-18-07
One possible experiment I came up with would involve a two counter setup and measure a flat rate of cosmic rays. We could set the detectors up in a stacked pattern and run them for set time intervals and monitor the comparison of cosmic rays reaching the detector compared to angle of the sun in the sky. So as the sun sets we we can determine if there is any change in cosmic rays reaching Earth. We could also keep running the detector after sunset to see if that effects our data. One thing that would help this experiment is the fact that over the next few weeks and months the sun will be setting earlier and taking a path across the sky at a lower angle. So if we ran this for the next few weeks it should give us an idea or not if the angle of insolation effects the rate at which cosmic rays strike Earth. Also we might be able to compare the rate of cosmic rays to the duration of insolation.
9-24-07
Last week in class we looked at the idea of error bars on our data graphs. The error bars are calculated by the square root of the number of counts that are taken. The error bars are calculated and then placed on the graph and if all of the calculations are correct the correct plot would fall within the error bars, most likely making a smooth curve. After that we got the chance to use the detectors in different ways to try and cause a noticeable change in cosmic rays detected.
The trial and error experiment
At first Abaid and I tried various different arrangements of the detectors. We placed them on thier side, upside down, and turned the middle detector perpendicular to the top and bottom detector. The problem we ran into was we were changing so many different variables it was hard to compare each set of data we took, although the detection rate changed drastically each time. So we started over and came up with a way to test a single variable. We kept the detectors the same and ran them for one minute and then turned the middle detector at a 45 degree angle to the top and bottom and ran it for one minute. Finally we turned the middle detector at a 90 degree angle to the top and bottom detector. As we hypothesized the cosmic rays went down as the angle the middle detector was turned to increased.
Data Results
Results on surface area
As you can see the amount of counts goes down as the angle of the middle detector increases. The biggest reason is due to the fact that in an inline setup all three detectors approximately 2800 square cm's of detection surface space line up. As compared to under 1000 square cm's of detector surface space when the detectors are perpendicular to eachother. By determining the difference between the two figures you should accurately be able to figure out the amount of counts at various angles or amount of surface space of the detectors.
One question that comes to mind when I think about how accurate I could be in my data, is how much data is enough?
Handy rule of thumb - look at the variations and make sure your error bars are
a few times smaller than that - if the error bars of 2 points overlap it is likely just statistical error - if they don't it is more likely a real effect - we can quantify this. Nice work
9-25-07
On Tuesday Abaid, Ted and I got the chance to take Cosmic Chris around the physics building. We were testing the effect of altitude vs. the rate of cosmic rays. We already had the idea that there was going to be an increase in rays as we went up in altitude. So we started on floor D which was the top floor and we took 3 sixty second counts and we did this for each floor all the way down to the basement. We made sure to align the detector in the same directional orientation and in the same place in comparison to the elevator. We then realized that the basement had one very important difference, there was no window. So we took the counter back up to the top floor and two others on the way down, we took the same amount of readings, except we moved into the middle of the hallway away from the window on each of the floors. We knew that if we did not see a difference in the number of counts, which we didn't, between the window and the hallway we could efficiently use our data, to compare each floor.
Media:Cosmic_Cris.xls
As you can see by the graph our data shows a consitent rate of decrease in the rate of cosmic rays as you go down each floor. One difference from this counter is that we were only measureing a coincidence between two counters instead of three.
10-2-07
In class on Tuesday, we were given the task of determining the velocity of cosmic rays. One interesting thing we had to take note of is the consistency of the equipment we were using. In order to measure the speed of the cosmic rays we had to know the distance they were traveling and how long it took them. The way we came up with to determine their velocity was by using the oscilliscope. By measuring the lag time between the peaks of the cosmic rays. We had to make sure the detectors had even lengths of wire, because by changing the length of the second detectors wire, we changed the arrival of the pulse. Once we determined the wires were the same length we began the experiment.
We started with the detectors at 13" apart and moved them to 26", after that we then moved the bottom detector to 54", 80" and 104". We hypothesized that the lag time between pulses would increase as distance increases and we were infact correct.
Media:Copy of Distance change in detectors.xls
If you look at our data the delay in nano seconds increases as we seperate the detectors. Once we added the error bars we took the steepest and gentlest slopes and cut them in half giving us the midway point and then we converted it to meters per second and that gave us out measurement for the velocity of the cosmic rays and we were within 90 percent accuracy of the speed of light.
10-9-07
Refined Data with X error bars
10-15-07
In class last tuesday, Ted and I worked on placing horizontal error bars on our data. What we did was measure the length of the detector and we already new the distance we moved the detectors down, so using the pythagorean therom we determined the hypotenuse angle of the right triangle, which was also the longest possible distance a cosmic ray could travel through between the two detectors. What we noticed is as the detectors moved farther apart the longest possible path got closer to the shortest possible path. When we put the error bars on the graph we realized that they were telling us that our data could have actually been off by more than we thought. So what we are going to do next is take different lengths of wire and use them to determine the speed of the cosmic ray. This will give us less error, because now we are fixing the distance, so there really won't be any error on a known distance.
One interesting thing I have noticed in the experiments we have done in class so far is the amount of variables we have to look out for. Obviously the less things that can change give you a more specific measurement, but it seems that it is extremely hard to single out specific variables of cosmic rays.
10-16-07
Speed through cable
10-23-07
The above data was from class on 10-16-07. What we did was try to determined the speed of the pulse through the coaxial cable created by the cosmic ray. We obtained 6 different lengths of RG58 cable 15 1/8", 39", 48", 62", 68" and 121". We then started up the oscilloscope and took three readings with similar length cables. At each length of wire we took three readings as well. We observed the pulse of the detector with the increasing cable length coming later and later with each increase. When we recorded our results we took the average for each length of cable and plotted it on the above speed through the cable graph. Cable specs The cable specs link shows the specs of the RG 58 coax cable we used. We determined the speed to be about 65% that of light and according to the link the actual is 65.9% so we were off by about .9%, which is not bad at all.
10-23-07
Data steps 10-23-07 Determining error of velocity calculation
1. Took 40 readings with same length cables
2. Put data into excel
3. Broke data into 1 second bins
4. Placed onto histogram
5. Determined average of the time in ns (all 40 counts)
6. Determined the standard deviation
Frequency Histogram
By making the frequency histogram, we were trying to get a bell curve, which was close, but not quite there or a visual for what our error should look like. 66% of the measurements were within 2 bins of the average.
10-30-07
What we were trying to do in class last week was gather more data to try and make our errors smaller. We decided to take 575 counts using the "elev" program, which electronically records the difference in pulse time and the difference in pulse intensity. We took 575 so that we would have atleast 500 useable counts. Once we obtained the data we used the data converter to make the data readable by excel, which we then pasted the data into excel. We then used the pulse heights to eliminate any inconsistencies or negative pusle heights. Then we made a histogram of the difference between pulses arrival times. Which in the data was the difference between channel 1 and channel 2. When we completed the histogram we noticed that we had a much better shape to our bell curve compared to using 40 counts.
error histogram
11-6-07
To date in class so far we have done various experiments involving cosmic rays. We have determined the rate of cosmic rays compared to altitude as well as the rate depending on proximity to a window or away from the window. We have also determined the speed of cosmic rays through the distance between two detectors as well as through RG 58 coaxial cable. To this point I have a few different ideas of possible experiments we could run over the next three classes. One idea I have is to use the two detector setup where we can move the bottom detector down a few feet and then place different materials inbetween the detectors and see if we can lower the rate of coincedence or possible change the speed. For example, if we put aluminum foil between the detectors would the foil deflect the particle, cause it to change speed or direction where it would miss the bottom detector all together. We could try a tray of water, foil, sand or any other kind of material. The idea would be to see if we could lower the coincedence rate or if we can change the speed.
11-13-07
Distance from under the bridge graph
11-13-07
On Tuesday the 13th, Abaid and I took Cosmic Chris on a field trip. The idea we had was to see how the bridge between the Physics and Math buildings would effect the rate of cosmic rays. Our hypothesis was, as we moved further from the bridge the rate would increase. We were also curious to see how far away we would have to get to see no change in the rate. We started directly under the bridge and moved 8.5 meters each time till we were 34 meters away from our starting spot. As the graph shows, as we moved from under the bridge the rate of cosmic rays increases. We stopped at 34 meters because from 25.5 meters to 34 meters there was only a slight increase in the rate. We stopped because of time, but in order to find out if this was far enough away for the bridge to no longer have an effect on the rate we would have to continue to move further away from the bridge until we no longer see a difference.
11-27-07
Distance from under the bridge, updated graph
To finish up our experiment from last class we took measurements at two more distances from the math to physics bridge. With these two measurements at 42.5 meters and 51 meters, it appeared that are rate of cosmic rays leveled out. Although it probably would still have an effect on the rate, because it would still be effecting the lower angle cosmic rays. We just moved into an area where there was nothing from the building effecting the higer angle rays. The reason it did not seem to effect the data that much would be due to the fact that a higher percentage of cosmic rays are coming from higher angles.
Distance from library cove graph
After we finished taking the last two data points for our brige experiment, we decided to do a similar experiment starting from the entrance way to the library, which also has a roof over it, except it is surrounded by 3 walls. We started from underneath and moved out 10 feet each time. At each spot we took three 60 second counts. When we graphed the information we noticed that being surrounded by three walls lowered the starting count about 10 percent, but eventually the count climbed up to a similar rate as the bridge experiment.
What we are thinking of trying next is a similar experiment, except possibly being surrounded by 4 walls and move towards the middle.
12-4-07
Our expeirment last class was an interesting one. We decided to take data in the library atrium to construct a topographic map of cosmic ray rates. We started from the far end of the library just before the atrium and under four stories worth of material. We took three 60 second readings at each of the five spots. When we went to spots 2 and 3, which were underneath the atrium we noticed about a 20 percent increase in the rate. From spot 3 to 4 and 5 we noticed about a 10 percent decrease per spot, due to a large 2 story cement stair case. At spot 5 which was the entrance way to the library the rate was back to the same as our start point, which makes sense because both spots have about four stories of library overhead.
Atrium X-ray & Outside data combo
In the above graph we put the inside library data together as if you started in the back of the atrium and walked to the front of the library, out the door to one hundred feet away from the building. The most interesting part of the data is that even something like a glass roof inside the atrium is enough to affect the rate of cosmic rays. Although, to understand how much the atrium truly affects cosmic rays, we would have to determine the rate at different angles and determine the percent that is coming in at an angle, which puts it through the library walls and not through the roof. Overall our data matches our hypothesis. The more overhead material you have above you or around you the lower the counts and the furthest from any obstacles you get the highest counts.
It would be interesting to see what a three dimensional graph would have looked like if we would have had time to take data in a third axis across the atrium at each spot.
