Tuesday, 20 March 2018

CSI Challenge/Guiding Gumshoes

We had already planned to work on the Alberta CSI Challenge when we received the latest Girls First testing activities - "Guiding Gumshoes", so we combined the two and had a great meeting. 

We started out with our usual opening, Horseshoe, Promise, and an active game - Squirt. Before getting started on our activities, we talked a little bit about what we were going to be doing and how the activities related to forensic science.

Our first activity was called Magnify My World. Here we downloaded a Powerpoint presentation (see links below) showing magnified images of a variety of different things. We showed the presentation on a tablet and had the girls try to guess what each image was before sharing the answer (if necessary). Images included toilet paper, a grain of salt, the head of a pin, a staple in paper, the claw of a black widow spider, and the bacteria found on the head of a pin.

We then played a few rounds of Handshake Murderer. One girl is chosen to be the detective and leaves the room. Everyone else closes their eyes and a leader taps one girl on the shoulder to be the murderer. Everyone opens their eyes and the detective comes back into the room. Players move around, shaking hands with each other. If some feels the other person scratch the palm of their hand, they have to take three steps then perform an elaborate death scene as they have been murdered! The detective tries to figure out who the murderer is before everyone dies. 

Next up was Fingerprinting. Everyone tried two different methods of making fingerprints - using graphite from a pencil and using washable markers. They decided that the washable markers made better prints - and they were much more colourful! Each girl made a pair of thumb prints to be used in a matching game later on.

Continuing with the markers, we tried a bit of Chromatography. Each girl used colours of her choice to make a design on a coffee filter. They were then folded into a wedge and the tip dipped in water. We left them on newspaper to allow the water to wick up the filter and then shared the results at the end of the meeting.

Our final activity was Extracting DNA From Kiwi Fruit. This is a fun - but messy - activity! Each group mixed up an extraction solution of 1/2 tsp salt, 4 tsp water and 2 tsp dish soap. They then smushed up a kiwi fruit in a ziplock bag until it was all pulpy. The extraction solution was added to the kiwi pulp and squished together. Coffee filters were placed over a glass, and the pulpy mixture poured in. The girls worked together to carefully hold the filters while one girl gently squeezed the bottom to help the liquid come through. While tilting the glass with the kiwi liquid, 4 tsp of isopropyl alcohol is poured down the side of the glass, forming a layer on top of the kiwi liquid. Between the two layers there should be a whitish blob that can be fished out with a skewer. One of our groups was successful in pulling out the kiwi DNA, while the other two groups could see the whitish particles, but were unable to remove them from the liquid. We have done this successfully in the past with strawberries and would recommend that fruit for future efforts. 


We ended the meeting with a couple of songs, reminders for next week, and Taps.


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