Fake activity 1 crime

transcript

Activity 1: What was the crime?

Objectives:

• Recall how the particles are arranged in solids, liquids and gases.

• Use particles to explain a process.

Hello, and welcome to your forensic science work placement. I’m Dr Sherl, your mentor. You must be Billie,

right?Yes, that’s me. I can’t wait

to get started! I’ve seen lots of forensics on TV,

but this is the real thing…

I’ve paired you up with Dragon, our other

trainee. Do you know what forensic scientists do?

Activity 1: What was the crime?4

Engage Elicit Explore Explain Elaborate Extend Evaluate

Absolutely right Billie! I hope you’re ready to start, because I’ve just received news of a major

crime.

A crime always leaves traces. Don’t forensic scientists use special techniques and try to

find evidence to pin the suspect to the crime scene?

It happened at an art gallery and it reminds me of a film. Watch this clip

– it might give you some ideas.

Police are reporting a strange break-in at a local art gallery. A rare and priceless painting seems to have been the target but the criminals may have escaped empty-handed; reports say the painting is still hanging in the gallery.A local police officer has told us that the case is being investigated by forensic scientists who are looking for clues to investigate.

It happened at an art gallery… the newspapers are starting to report the story.

There’s not much evidence so far – just a statement from the duty guard. You might find

the crime scene drawing useful, too.

One of the rooms with a priceless 17th-century painting

looks like it’s beenbroken into.

Here, take a look.

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So Billie, how can we find

out what happened?

Yes – but it might have been tampered with. Maybe we

should check if it has been touched.

How can we do this?

We have to figure out what the crime was.It must be something to

do with the painting – but it looks fine!

Just look for fingerprints, Billie.

It’s easy – his fingerprints will be

all over the frame!

OK. But how can we find them?

Whenever you touch a surface, you leave

traces of oil from the ridges on your fingertips. These hidden

fingerprints show up if you brush charcoal dust onto the prints.

The charcoal sticks to the oil.

I tried this out and the fingerprints got all smudged. We can’t use

fingerprints like these as evidence to help solve a crime.

OK Billie. Can you find a better way of showing up

fingerprints?

I’ll give you three

substances to investigate.

You need a substance that:is colouredsticks to oil does not need

brushing onto the prints (to avoid smearing).

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Dr Sherl has lent me her book. It shows us how to use iodine to show up hidden

fingerprints on the frame.

This technique looks great – I’ll try it.

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Activity 1: What was the crime? 17

Particles? What are they? And why do

they matter to forensic scientists?

Hmm. How does iodine show up the fingerprints? I think maybe iodine moves to the fingerprint, but

how? It doesn’t look like it’s moved…and the lump of iodine doesn't get any smaller. Better ask Dr

Sherl…

OK Billie,I’ll give you a clue.

It’s all to do with particles.

If you take a solid and cut it

in half again and again, you will eventually get a bit that is just too small

to cut up.

What would this piece look like if we could zoom in on it?

Substances can exist in three forms: solid, liquid and gas. These are the states of matter. In each state, the

particles are arranged differently,

and move differently.

If we transfer energy to or from the substance, its state changes.

When iodine warms up, it doesn’t melt like most solids. It turns into a gas. This change is sublimation.

I tried the iodine out and it worked! It showed

up a couple of thumbprints on the front, and lots of fingerprints on the back.

So we’ve gotour man…

Unknown prints

Gallery owner’s prints

Well, we’ve got some more

evidence, but we still can’t be sure what happened …

or who did it.

And Dr Sherl keeps going on about

how particles are so important to

forensic scientists…What does she mean?

Have a think about it, Billie. Without particles,

you and Dragon would never have found the fingerprints.

Explain why.

Now can you explain why particles are so important to forensic

scientists?

Picture Slide Credit

Picture credits

Activity from the Forensics unit © Association for Science Education and Centre for Science Education 2010.Teachers and others who download this material may use it freely within their institution.

For any other usage consult the upd8 team, upd8@ase.org.ukASE and upd8 are not responsible for any revision that may be made to the material after it has been downloaded.

Fake activity 1 crime

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