Continuing Creations

1/25/13


 Daniele Heather and I spent most of today gathering the three different experiments we had running in the kiln last week. Daniele had already taken the sample we put in the kiln at 750 degrees Celsius so we headed off to the lab to extract our materials. To open the vacuum sealed tube, Daniele simply took a hammer and cracked one end of the tube open, leaving the sample at the other end of the tube easier to extract. We then began to scrape the sulfur from the sides of the capsule. After prying the sphalerite mineral from within the hardened sulfur, we placed it in acetone to try and get rid of some of the excess sulfur. We also squirted some ethanol into the capsule which helped remove the sulfur from the sides of the capsule, allowing us to recycle as much of the sulfur-34 as possible. After this, Heather informed me of how the galena minerals we had begun to polish last week had accidentally been left polishing on the machine and had polished away into thin slivers of galena. Heather then presented newly polished galena molecules that practically shone like mirrors. We then headed off to the furnace room to remove the other two experiments that we had in the furnaces. After removing the capsules form the furnace, the sulfur was glowing its customary blood red color. We set the capsules down on a metal plate to cool before taking our experiments back to the lab. I tried to crack a capsule with the hammer, and though my initial attempt was under zealous  my second was a little too enthusiastic as I sent glass all over the counter. Luckily the sphalerite and sulfur remained at the bottom of the capsule rather than flying across the lab. After cleaning up the glass I set to work trying to scrape off the sulfur. However, the sulfur was stuck firmly at the bottom of the capsule encasing the galena mineral. We left the capsule propped up in a beaker and full of ethanol to try and wear down the chunk of hardened sulfur. Due to my energetic hammer wielding, there wasn't much of a capsule left, and the sample was propped up in the smallest beaker I have ever seen.

The tiny thumbnail sized beaker amused me to no end and held the galena capsule as I moved on to try my luck with the hammer on the second capsule. Luckily I had found the correct medium between not making a dent and shattering glass and was able to successfully gain access to the sample within without mishap. However, the sulfur had also formed a stubborn chunk within this capsule so we left it to soak in the ethanol. While the samples were soaking, we decided to clean off the polished galena minerals. They were attached by the crystal bond to the metal disk so we put the disk on a hot plate to melt the crystal bond. We then removed the galena minerals from the goo with tweezers and placed them in an acetone solution to remove the rest of the crystal bond. Heather than showed me the galena mineral under the microscope which after a couple minutes of careful angling so as not to catch the reflecting light of the microscope, we managed to get a great picture.

After taking the picture, we scraped off a little more of the sulfur, but the minerals still remained trapped within. Daniele then had me seal the ends of a couple glass tubes so we would have some tubes ready to go for future capsules. Luckily I have gotten much better at sealing the tubes and Daniele gave me the seal of approval with every completed tube I showed her. We also put some sphalerite and recycled sulfur in a capsule to run another experiment at the higher 750 degree Celsius temperature. At this stage in our experiment, we are still collecting data on the diffusion of sulfur in the sphalerite and galena minerals. Next week we will continue working on capsules and maybe begin to analyze some data.

Galavanting with Galena

1/18/13

Today Heather, Daniele and I got quite a bit of work done. Right off the bat Daniele decided that we should try and diffuse the sulfur through a new mineral. Just like the sphalerite, we would use another sulfide called galena. We spent a couple minutes looking for a galena chunk with a smooth surface. This is because since we are measuring how far the sulfur diffuses through the mineral and the sulfur only diffuses a very short distance, it is important that the mineral has a level surface. That way the data of the diffusion across the face of the mineral is consistent. After picking out a prime candidate, I quickly filled the capsule with sulfur and then hooked it up to the vacuum before sealing it. Here is a picture of the crazy goggles I have to wear to protect my eyes while sealing a capsule:

Luckily there were no flaming incidents and I made the capsule easily. Here is the finished product where you can see the furnaces in the background:

We put the capsule in a furnace at 300 degrees Celsius and then headed back to the lab to work with the galena. Since galena does not have the same crystal formation as the sphalerite, the minerals do not naturally cleave to have very smooth faces. As a result, Daniele, Heather and I decided to polish some of the minerals in order to achieve the necessary smooth surface for sulfur diffusion. To do this, we took little circular disks of metal and placed crystal fragments with a very low heat tolerance on the disks. We then placed the disks on a hot plate and melted the fragments into a sticky goo. Picking galena pieces of approximately the same width, we pushed them into the goo. After the disk was taken off the hot plate and the goo allowed to cool, the galena chunks would be held in place for polishing. We polished the mineral basically using strips of sandpaper. We started off with a very rough sandpaper to try to generally start smoothing the bumps in the galena chunks. We then used a smooth sandpaper to begin to work out the scratches. The sandpaper is shown below and I am holding one of the metal disks with the galena chunks on it:

After the sandpaper, we placed the disk in a machine, that sanded the disk back and forth across a mixture of a powder and tap water. The powder contained a special substance that had a even smaller grain to continue to smooth out the surface of the galena on an even tinier scale. While the machine was working, we made another capsule, this time containing our usual sphalerite. We decided to run this sphalerite trial at 750 degrees Celsius to see what results we would get from experimenting with sulfur diffusion at a higher temperature. After finishing the capsule and putting it in the furnace, my time was up and I had to leave before we could get some computer work done. Daniele has promised to show me the programming set-up next week which hopefully will go well.

Zany Zircons

1/11/13

Heather emailed me informing me that we will start meeting next week. Though I did not get to work with sulfur diffusion this week, Ms. Mroczka emailed me an article about zircons, the minerals Dr. Bruce Watson is working on. It turns out that zircons are the oldest rock discovered by scientists on Earth at an impressive 4.4 billion years old. The really interesting thing about zircons is how much they can tell us about the world 4.4 billion years ago. As rocks grow, they form bands, picking up surrounding minerals or any other substances in their path. Therefore, from the zircons, we can figure out what minerals were present on very very early Earth. From this information, Dr. Watson found that titanium had been present at this time and based on the quantity of titanium, Dr. Watson could estimate the temperature of Earth during the time the zircons formed. The important information that Dr. Watson derived from this information was that rock that crystallize at the temperatures he calculated need water. This means that according to Dr. Watson's zircons, water was present on Earth 4.4 billion years ago!

Dr. Watson has a few quotes in the article Ms. Mroczka emailed me, which can be found here: http://www.npr.org/blogs/krulwich/2013/01/10/169047159/the-oldest-rock-in-the-world-tells-us-a-story

Molten Mixtures

12/7/12-12/14/12

Though Heather was still in San Francisco, Daniele was at the lab and told me about the conference. She had presented to an overwhelming 20,000 scientists at the conference and luckily it had gone well. Daniele and I spent the day taking the capsule out of the furnace that we had put in last week and extracting the sphalerite and sulfur. When we took the capsule out of the furnace, the molten sulfur-sphalerite mixture was a glowing red. Daniele explained that the previously yellow chunk of sulfur turns red when it reaches molten temperatures. After the capsule had cooled, Daniele and I used a hammer to break the glass of the capsule. The popping sound we heard when we broke the glass confirmed that our vacuum within the capsule had remain intact. The sulfur and sphalerite had returned to their previous yellow color so I worked to recycle some of the sphalerite on the no longer molten mixture. I scraped the sphalerite from the sides of the capsule and put it in a container to use in our next trial of experiments.We removed the chunk of sulfer (which the sphalerite molecules had hopefully diffused through) which Daniele will take to Albany to analyze.

The next week Heather had returned from the conference. Heather decided that today would be a good day to find the hotspot of the furnace we had fixed two weeks previously. The hotspot is the area of the ceramic tube within the furnace that reaches the highest temperatures. All of the experiments should take place at the hotspot for consistency and so that the experiment receives the maximum temperature. The experiment is always lowered into the ceramic tube with a thermocouple to measure the temperature so to find the hotspot, we measured the temperature within the ceramic tube every 0.5 centimeters using the measurement markings on the thermocouple. Though it was time consuming to go centimeter by centimeter, waiting for the temperature to regulate at each new location, we finally found the area where the temperature peaked. Measuring the hotspot took up most of the time we met, but we had enough time for me to make a capsule on my own. Luckily, this time I did not send any flaming glass flying across the lab and successfully made my very own capsule assistance-free. We placed the capsule with the sulfur and sphalerite into the furnace at the newly-found hotspot and then headed into Daniele's office to look at some data. Daniele showed me graphs from her previous experiments with sulfur diffusion. Though the programming tools used to make the graphs showing the sulfur diffusion are still a little mystifying to me, Daniele said that second semester would focus more on organizing the data we have collected from our capsules. Hopefully practice will make perfect and I will be able to figure out the programming!