7th Grade Science Fair Interviews

by Liz Zarikyan 

     This year’s Science Fair, which took place February 6-8th, was a showcase of projects from 7th and 8th grade students that uncovered mysteries, revealed solutions to some of our world problems, and even provided resources to use in case of emergency. I interviewed some of the 7th grade winners to find out more about their projects.

Jordan R. – Honorable Mention – 7th grade

What was the title of your project?

The Effects of Proteinase K on the Biodegradation of Plastic

Why did you choose to do this project?

I was interested in finding a way to safely degrade plastic because I’ve seen plastic pollution and have wondered how that problem could be solved. Only around 9 percent of plastic is recycled so I started my research to see if there was any way to eliminate it. I thought this method was a good option for dealing with the problem, and Proteinase K got my attention due to its ability to degrade the polymers in plastic. The surrounding soil is used through the existing microbes that consume the lactic acids which are created when the polymer is broken down by the enzyme.

Did you have any complications when working on your project?

It was hard to find proteinase K, which is an enzyme used in molecular biology. It was hard to find because it’s not an item that’s bought on a day-to-day basis, making it less available. I didn’t consider purchasing other enzymes because I researched other “digestive” enzymes such as lipase and I found that they would not be effective on plastic. I originally tried to obtain the enzyme from BLIRT, which is the primary European manufacturer of recombinant enzymes, but after applying for an offer and not getting a response, I searched for other suppliers and was then able to purchase it on eBay.

What was your process?

I tested the effects of the enzyme on the plastic by embedding the different amounts (0 mg, 10 mg, 40 mg) into 50 g of soil and then using that to cover plastic disks that came from disposable food containers. After 2 weeks of putting these out in the sun, I used Image J,  which is a Java-based image processing program that provides the function of calculating the surface area within an image.

What were your results?

Proteinase K helps biodegrade plastic by a decent amount. 40 mg of Proteinase K was able to lower the surface area of plastic by over 8% in just 2 weeks.

 

If you could do this experiment again, what would you change?

I would run more trials because I want to test out increasing the amount of enzyme and/or composting time period. 

What was the best part of your experiment?

The best part of the experiment was seeing how the plastic had degraded. I was interested to see how the experiment would turn out and was happy that it worked. 

 

 

Paria V. & Kayla A. – tied for 1st place – 7th grade

What was the title of your project?

“Water on the Go: Creating an Emergency Water Filter”

Why did you choose to do this project?

We set out to create a water filter that could be used while hiking with available water, so we wanted to find out how much cleaner you can make dirty water through a mechanical process. Also, there is a shortage of clean water around the world due to natural disasters and human-orientated events, and this process could possibly allow for places around the world to have drinkable water. 

What were your results?

We measured our results using a TDS meter. The TDS meter measures parts per million (PPM) of dissolved sediments in a substance. In our first trial, we had a starting PPM of 311 and a resulting PPM of 273. In our second trial, the starting PPM was 357, and it resulted as a PPM of 303. In our third trial, we started with a very high PPM of 493, which is close to the highest contaminant level and highly dangerous to consume. The resulting PPM was 343,  which was a very significant change. It brought water with an almost max contaminant level down to the same PPM as tap water.  

What was the best part of your experiment?

The best part was testing each layer before putting it in the filter to see how it would filter dirty water on its own. The layers we used were two pieces of foam on each end, then a starting layer of charcoal, then sand, then small rocks, and lastly, a final layer of charcoal. These layers were separated by a small layer of straining fabric so they wouldn’t mix. We decided to add another layer of charcoal, because we found that it was the best filtering factor. Something interesting we found was that when you pour water onto activated charcoal, at first it will sizzle and bubble. Afterwards, the water started to run clear, showing that the charcoal did a lot of the work. The activated charcoal strips out the toxins and odors in the water. The sand and rocks removed the larger sediments before reaching the last layer of charcoal. 

What was the process after you figured out your layers?

We drilled a hole into the cap of a bottle and cut the bottom off. We then sealed a coupling into the drilled hole with waterproof silicon to ensure it wouldn’t leak. Next, we attached tubing from the coupling to the main filter and in the middle placed a valve. The valve starts and stops the water flow. This part of the mechanism does not affect the results of the filter, but it does make the filter easier to use. 

Did you have any complications when working on your project?

It was hard to drill a hole in the bottle cap, and it was hard to get the cloth pieces in the tube. We also had an unexpected trial when testing our filter when the PPM actually increased, meaning the water got dirtier.  This was a result of us not compressing the layer enough, so the sediments got stuck in between the layers. 

If you could do this experiment again, what would you change?

To improve our project we could add either a solar panel pump or a hand pump. This is because our filter was a bit slow because of the many thick layers. This would pump in the water, making it faster and more convenient. A hand pump would be added in case a large amount of clean water is needed in a short amount of time. We could also add a stand because it took two hands to hold the filter. If a stand is added, then the filter would be completely automatic and convenient. These add-ons are not necessary for the filter to work in case of an emergency, but they would be very helpful.

 

   

Final filtration process