Tuesday, 7 July 2015

What Evidence Would You Collect?

You enter a house and you see broken glass, the tables and chairs are toppled over, and it’s so messy. To your surprise, you also see a knife on the floor and it has some blood on it!

Depending on the type of crime and how it was committed, there can be many different types of evidence at the scene. There might be fingerprints on doors or windows, on drinking glasses left on tables, or on many other objects around the scene. In some instances, there may be samples of blood, hair, or discarded clothes. One of the hardest things for a forensic scientist is separating out the really important evidence from all the other things they may find.

Fingerprints are patterns of tiny circles and swirls, and ridges and valleys on the tips of fingers. They are there to help us get a better grip on smooth surfaces, like holding on to a pen when writing or holding a drinking glass. Each person’s fingerprint pattern is different, and it was formed before birth. 

No two people have the exact same fingerprints – not even identical twins. The three typical types of fingerprint patterns are arches, whorls and loops.
Our skin, including our fingers and palms, has microscopic sweat glands that secrete a substance consisting mostly of water and salt. When we touch things, a little of that sweat gets left behind, making a print.
Fingerprints have been used by governments all over the world for more than a hundred years and are still the most widely used form of identification. 
Now, look at your thumb. What type of fingerprint pattern do you have?

Experiment: Collecting fingerprints

Talcum powder, brush with soft bristles, clear sticky tape and magnifying glass.

1. Pick an object which you think someone has touched it. 
2. Gently dust some talcum powder on that object using the brush.
3. Lift the fingerprint with a piece of clear sticky tape and stick it on a piece of paper.
4. Observe the fingerprint with a magnifying glass.
5. Compare that fingerprint with your own. Use an ink pad to cover your finger with ink and press it down on the paper next to the fingerprint that you have collected.

Glossary of terms:
Microscopic [mahy-kruh-skop-ik] very small; tiny
Glands [gland] a group of cells or organs that produces a secretion

Shared by Surain A. Victor
Guest Blogger

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