Larger-than-life science guy Alan Nursall takes science on the road and challenges YOU to learn in a hands-on rodeo of discovery. Watch Big Al take on the delicate science of forensics, with the latest three-parter.

<< Click to watch the second part of Science and the City's Forensics special here and read Alan's journal below.


Thanks to all the great people at the Trent University Forensic Science program!

Fingerprinting and... superglue?
Science and the City visits the Forensic Science program at Trent University! In this piece, we head out to their creepy Trent U Forensic House and, using our high-tech portable forensic lab consisting of an aquarium and a light bulb, we put cyanoacrylate, or superglue, to the fingerprint test!

There's little mystery about how important fingerprints are in forensic science. We all carry ten unique signatures at the end of each finger, in the form of swirly, sinuous ridges.

We have fingerprints because they play a huge role in the effectiveness of fingers for grasping objects. They provide surface roughness that in turn provides the friction necessary for us to hold onto things. And when your fingertip comes in contact with a surface, those ridges leave behind a witch's brew of sweat, proteins, oils, and dozens of other organic and inorganic materials that ooze out of our skin. (Hey, it's all part of being alive!)

One of the most common ways to make those fingerprint patterns visible is to introduce a chemical that will react with the residue and increase its visibility. So how does superglue enter into this?

It has a lot to do with why superglue is so good at gluing your fingers together. The active chemical is 'cyanoacrylate', a resin that hardens almost instantly when it comes in contact with water, or more specifically the hydroxyl ions found in water. Your skin is covered in water. Cyanoacrylate loves surfaces like skin. Can we use it to find fingerprints? Watch and find out!


Finding blood!
All that glowing blue stuff that we see on TV crime shows? Looks like chemistry, but what's really going on?

In this Science and the City, we throw blood around inside the Trent University Forensic House, because that's the sort of thing you're allowed to do there. Fortunately, the blood came from the butcher and not from any member of the crew!

Once we had the blood in place, it was time to test the chemical reactions that lead to chemiluminescence, the glowing effect so frequently brought into play in crime investigations in the movies and on TV. Why does blood glow, and what else might trigger the reaction?


DNA profiling
What can food colouring teach us about DNA profiling? We test that question on this episode of Science and the City! Within the menacing walls of Trent's Forensic House, we look for patterns in the molecular structure of food colouring, and in DNA.

The secret is something called 'electrophoresis', which is a word that seldom comes up in polite company. Not because there's anything rude about it - it's just that most of us have no idea what it is. In a nutshell, electrophoresis uses an electric current to induce the movement of materials through a conductive medium. The rate at which materials move depends to a very large extent on the size of the molecules.

DNA - deoxyribonucleic acid - is a very large molecule. It resides in the nucleus of almost every cell in our body (no DNA in red blood cells, because they have no nucleus) and the precise structure of that molecule is unique for each individual. We'll explore the hows and whys of applying electrophoresis to establishing a unique DNA profile!