Capstone #6 Practicing My Presentation

I finished my script, and I am ready to start practicing. I freestyle practiced a few times without any script. The first time I said my script it sounded pretty bad. It had so many errors so I changed it. I read it again and I changed it some more. I practiced so much and I hope it pays off!

I changed my script in my head but here was my final script. But, to this day it sounds different every time I say it.

Welcome. I have a couple of things to say before we begin. I just want you to remember these to chemicals: Phenolphthalein and Hydrogen peroxide. Just keep those in your mind. It will be used later on in the presentation. Before we begin my Capstone is about Forensic science, and I will be drawing a TED talk for you today “What is Forensic science?” You may ask. Forensic science is where you take DNA run it through tests and you use that info to catch criminals. I will be explaining this through a story. Not just any story. A boring story. I’m just playing around. I hope. This story is about a crime and I will show you how the forensics come into play. Alright, now let’s begin.


There is a crime scene everyone is there. Flashing cameras, cops holding back the people and the press. In between all of that chaos there’s the detective. He is inspecting the man’s body. He searches his pockets and finds a receipt for a scratch ticket. The time says he bought it at 5pm, the time is currently 11pm so he has been dead for a most 6 hours. They also find his ID and his name is Arnold. But that’s irrelevant. There are some practises to see how long he has been dead. Its where if the body has been dead after 2 hours, the position the body was in will start to change and the body will contract. Which means it will end up straight after 36 hours. He is still contracting so that means he died probably right after he left the store.  


There’s not much evidence to gather so they go to the store where Arnold bought the scratch ticket. They check the security cams and see Arnold walking out of the store with his bag. Then a man behind a tree follows him shortly after. So, we will give this situation the benefit of the doubt and assume he is a suspect. So now we know he’s a suspect. In the meantime other investigators find other suspects. The find them with logic and look through every possibility. For example the other store workers or people at the store at that time. The detective asks the store owner for the workers name. They show him the footage. It’s really blurry and most TV shows would just enhance the footage and then find the workers name. But it’s not that simple. You can’t enhance a blurry image. That’s like saying you can make a picture better quality after you take it.   But the quality is good enough for the owner to recognize the person. He was a worker indeed and his name is Bruce. They check the store for any evidence and they find a wrench, with a red stain on it. If the detectives are suspicious about the wrench, witch I would definitely be, they take it back to the lab as a possible murder weapon. Evidence should always be well preserved. Weather it’s putting it in a plastic bag or freezing temperatures it always needs to be put where the specific chemical on the object can survive.


There is a special way to check if the red stain is blood. Remember those 2 chemicals? Good it’s ok if you didn’t. Those are special chemicals one might say. Take a cotton swab and take some blood from the wrench. Spray some Phenolphthalein on to it. Then a couple of drops of Hydrogen peroxide. If it is blood, the chemicals inside of the blood would react like an allergy. It would turn pink. In this case, it does. So now Bruce is a big suspect. They take the wrench and run it through a DNA scanner. One specific brand is called the “MiSeq” It’s a pretty new model that shows you a bunch of DNA enhanced a TON. It prints out a pattern combination. Remember this as well. The DNA patterns on the wrench match no suspects so, they go to the store collect some DNA from Bruce run it through the scanner. It has the same as the wrench. So, the murderer is Bruce.


They go to the store owner and ask him where Bruce is. The owner says he will be at work the next day so they wait. On average each forensic science case takes about 56 hours. (2 days and 4 hours) The next day they arrest him and use the wrench as evidence. Next you put all the info on the case in the case file. Case files are an organized way of keeping crimes in a saved place.


Now for everyone’s favorite part, bare with me for one more minute. Fun Facts. Did you know forensic science dates back to 44 BC? Do you still remember those patterns? Only 6 other people in the world have the same DNA patterns as you! Everyone is probably wondering this: what does DNA stand for? It stands for DeoxyriboNucleic Acid. Also you have 4 types of DNA bases: A,S,T, and G and all the bases together make up the big number 6 BILLION.  


I couldn’t have done any of this without Ron. Ron is my dads friend that helped me gather some info on DNA tech that we use today. All the people at his office in Cornell University were very open to their studies. Have wonderful day at cap con. Thanks for coming to the lab!       

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