Microscopy Flashcards Preview

Biology; Detection > Microscopy > Flashcards

Flashcards in Microscopy Deck (16)
Loading flashcards...
1

Why do police tape off a crime scene?

So that no one touches the evidence before forensics gets to it

2

What is forensic science?

Forensic science is the study of materials and situations that relate to crime. Forensic scientists gather and study evidence so that it can be used in a court of law.

3

What are microscopes used for?

To examine small bits of data. To small to see with the naked eye.

4

What are microscopes used for?

To examine small bits of data. To small to see with the naked eye.

5

What if a normal microscope is too small to see the evidence?

You have to use an electron microscope. These are very powerful microscopes that provide better magnification and resolution.

6

Define magnification;

How many times bigger the image is compared to the object.

7

Define resolution;

How clearly the microscope can distinguish two separate points.

8

Define resolution;

How clearly the microscope can distinguish two separate points.

9

Converting Units; A typical cotton fibre is 10 micrometres wide. Convert these;

1cm = mm

1mm = micrometres

8cm = mm

6mm = micrometres

3500 micrometres = cm

10 mm

1000 micrometres

80 mm

6000

micrometres

3.5 mm = 0.35 cm

10

Microsope   |   Light   |   Electron
Radiation source                                                          electrons

                                                 up to 1000 x           

Resolution                                    small                            

Image                                                                       black and white

Microsope   |   Light   |   Electron
Radiation source                          light                          electrons

Typical magnification            up to 1000 x           up to 1 000 000 x

Resolution                                    small                            large

Image                                           colour                 black and white

11

Name (5) samples of what forensic scientists might anaylize.

What do they do with their anaylsis.

Hair
Fibres
Paint Flecks
Pollen Grains 
Soil

Try to match these with whats on the suspect or victims clothes or body.

12

Why are Pollen Grains useful?

Pollen grains come in differnt sizes, shapes and surface texture.A pollen sample can make evidence that a suspect was at the crimee scene.

13

What's useful about Clothes Fibres?

Clothes fibres can match a suspect to the crime scene or a suspect and a victims hair/clothes

Clothes fibres look very different under the microscope.

14

State one difference between the apperence of cotten and wool fibres.

Wool is very seperate and rigid.

Cotten is smoother and closer together. Cotten also twists together.

15

What's the one downside to using this technique for evdence?

Even though it may confirm a suspect was there at th scene of the crime it doesn't determine when.

16