Electronic Journal for: Amit Aravapalli 

1. 11/7/00

2. 9:50 – 10:40am

3. Evan described our setup to us.  We are using the intravelometer software on a laptop.  The software allows us to put in an interval time for three flashes and a delay time for the first flash.  We familiarized ourselves with the software and the equipment.  We tested out the flashes and made sure our equipment was working.  Then we started this electronic journal.  In our next session we are going to work with setting up the laser and hopefully start working on the timing. 

1.      Date 11/7/00

2.      Time 3:30-5pm

3.      Description of what you did, what you learned, and what you will do in your next session.

We initially started with a laser to trigger the flashes but this was not working.  We switched to a sound trigger and setting this up took some time.  We learned that the laser would not trigger the flash in time so we had to switch to a sound trigger.  We also spray painted six white cans so that the color filters on the flashes would appear on the cans.  In our next session, we hope to get the timing right for our flashes. 

1. 11/8/00

2. 2-3:30pm

3.      We took our first picture using the white can.  The picture was not desirable because three of the flashes went off after the can already had crushed.  In our next shoot we are going to decrease the interval time between the flashes; we are hoping to catch a high speed image of the can when it initially starts crushing to when it ends crushing.  We want to get successive frames of the image and we also want a successive contrast in colors, which we are not getting.   Our immediate delay (1^st flash) is .0006ms and our interval time (for 3 flashes) is 30 ms.  In our next session, we are going to change the interval time to 6ms and take more pictures.

1.11/9/00

2. 8-8:50am

3.Today we examined our first picture on Dr. Winter’s computer.  He said that we are probably getting images of the can before it has crushed and after it has completely crushed.  The interval time was too long because the three flashes went off after the can already crushed.  We therefore set our interval time smaller to about 6ms.  We need to find out the duration of the implosion so we can know how to set our time intervals.  We really did not have much time today but we are coming back tomorrow afternoon.  Hopefully tomorrow, we can start get some desired images but I think we have a decent start.

1.11/10/00
2. 3:30-5pm

3.We examined our second picture on Dr. Winter’s computer.  We had four flashes: red, green, blue, and orange.  We had a hard time seeing the second flash: green color.  Therefore, we decided to take pictures of the individual flashes on white can to determine what color each flash was giving off.  We discovered that the green color flash was actually giving off a bluish image on the can.  We perhaps thought that changing the resolution would affect our image colors.  We took another image keeping everything the same except changing the resolution from normal to fine.  The picture color did not change.  Therefore we learned that changing the resolution on the nikon does not change color of flash in picture.  Dr. Winters suggested that we take out our green flash and just go with three outputs.  Therefore, on Monday we are going to use three outputs: red, blue, and orange.  We are going to keep the interval time: 6ms and delay time: .0006ms.

11/13/00 and 11/14/00 – we turned in our project schedule for this week and made corrections to our journal entries.

1.11/14/00

2.3:30-5:00pm

3.Today we did not plan very well because we only had two white cans to take pictures with.  The first picture, Rob did not hold the can correctly because he did not fully submerge the can into the water.  Consequently, the crush of the can was quite different.  The second time Rob made sure to hold the can so that it would submerge into the water.  The outcome was successful and we got the picture of the can using three outputs (red, blue, and orange).  The picture had all three distinct colors in successive frames of the can crushing.  We learned that the can must be fully submerged in the water for it to crush properly.  After this shoot, we went outside and painted some more cans.  In our next shoot we are going to analyze our pictures

1.11/15/00

2.1:00-2:30pm

3.Today we had some problems with the triggering system.  We switched to Rob’s camera because another group wanted to use the nikon.  We switched the outputs to four ( red, blue, orange, and green).  We took pictures of individual flashes to see how Rob’s camera would display the filter colors.  Rob’s camera (olympus) displayed the green filter as green color on the picture.  We decreased the interval time to four ms and got two decent pictures.  We are coming back this afternoon to paint cans.  In our next shoot, on Friday afternoon, we are going to take more pictures with the time interval at 4.5ms and keeping four outputs.

Did not come to class 11/16/00 because we painted cans Wednesday afternoon.   

1.11/17/00

2.3:30-5:00pm

3. We got off to a slow start but things picked up.  We initially had some trouble with our trigger box, but we changed the battery and everything worked out.  We took a number of pictures using four flashes (red, blue, orange, and green).  We took pictures with different time intervals varying from 3.5ms-4.5ms.  We used Rob’s olympus camera again.  We had painted a number of cans the day before, so we were able to take a number of pictures today.  In our next session, we are going to spend time analyzing our photos and measuring the acceleration of the implosion.  We also did a better job recording our pictures.   

1.11-20-00

2.1:00-2:35

3.We analyzed photos from our last shoot.  Our main objective was to obtain multiple-image photos that clearly defined the distance traveled by the can within a given time interval, which we accomplished. We also want to find the average acceleration of the can as well as the average force that caused this acceleration (ambient air pressure). We measured the velocities by finding the change in distance (measured on the picture) divided by the change in time (interval time).  We then graphed the velocities for each picture and fit a line to it.  The slope of the line is the average acceleration. Basically, we printed out several pictures and analyzed them.   

1.11-21-00

2.9:50-10:40

3.We compiled all of our velocities and analyzed the data.  We also talked about the Physics involved in our experiment.  Dr. Winters stated that we probably will not take any more photographs because there is not much time.  He wanted to take a look at our data at the end of the class period. 

Velocities

Examination of our average accelerations indicates that most of them fall between 320-470 m/s/s.  The one outlier is for Cans4006.jpg which yielded a value of 1150 m/s/s because the can crushed slightly initially and then crushed drastically by the next flash, resulting in a greater average acceleration.  Excluding our outlier, we get an average of the average accelerations to be 402.8 m/s/s.

1.11-27-00

2.1:05-1:50PM

3.Dr. Winters gave us the guidelines for our report and website.  We decided to divide up the tasks among the group members.

1.11-28-00

2.9:40-10:40AM

3.Today we started our web page from our zip disk.  I worked on the data table while Rob worked on the theory of the implosion.  I am going to finish the data table for homework. 

1.11-29-00

2.1:00-2:30PM

3.Today we inserted the things we did into the web-page.  Rob made some diagrams on paint.  Rohit worked on the actual page.  I started typing the objective and setup on Word. 

1.11-30-00

2.8:00-8:50AM

3.Today Dr. Winters took pictures of our can setup.  Then we just cleaned up and worked on our report.  We also planned what we would have done by tomorrow.

1.12-4-00

2.1:00-2:30pm

3.Today we made the outline for our web-site and divided up the tasks.  We also talked to Dr. Winters about our report and he told us that we had quite a bit of work to do by tomorrow.  We decided what each of us would do by tomorrow to have a completed report. 

1.12-5-00

2.9:50-10:40am

3.We worked on our web-sites some more.  We edited images and inserted them into our web-page.  Dr. Winters talked about the software program that we had used for our experiment.  We included this program under our references in our written report.