Time for our next unit…• http://www.youtube.com/watch?v=7WseRJMQf1U

Forensic Science – “How can science solve crime?”Expected Learning: to introduce our Forensic science unit – “how can science solve crime?

Getting started

Date Focus Page Number Homework

• On the next blank page in your books, write the heading “Forensic Science – how can science solve crime?”

• Draw the table below and make it fill the WHOLE page• Each lesson you should fill in the table to help keep

track of what you have done and help you study for tests

Prior Knowledge Quiz

What is the main reason the police secure a crime scene?• A – To stop people minding other people’s business and

gossiping• B – To protect eh public from being harmed by anything lying

around the crime scene• C – To ensure that vital evidence is not altered or destroyed• D – To stop people from seeing something that might distress

them

Which statement about fingerprints is false?• A -Identical twins are the only people who have the same

fingerprints• B – Fingerprints consist of perspiration and oils• C – Fingerprints can be detected by dusting fine powders onto

areas people touch• D – Magnetic powders can help lift fingerprints off plastic bags

Which of these separation techniques can quickly help determine which brand of pen a suspect used?

• A – Filtration• B – Distillation• C – Paper Chromatography• D - Centrifuging

What is the principle by which every forensic scientist works?• A – Every culprit will be caught sooner or later• B – Every contact leaves a trace• C – Every piece of evidence tells a story• D – The more evidence you find, the greater the chance of

solving the crime

Everyone who witnesses a crime will be able to provide the same description of what occurred?• A – True• B - False

A forensic scientist’s job is to solve crime• A – True• B - False

The slight indentations that form on one sheet of paper that is underneath another that you are writing on are sometimes called imprints

• A – True• B - False

Used chewing gum can provide useful evidence at a crime scene• A – True• B - False

Answers:• C• A• C• B• B• B• A• A

• Tally your answer out of 8.

Prior-knowledge Activity• On a piece of paper, write down your answers to the following

question:• List all the words you can think of to do with “crime” • What does a forensic scientist do?

• OR

• Have a class discussion about the following two questions:• What is crime?• What are some examples of crime? • What does a forensic scientist do?

Key terms• Crime – an act committed in violation of a lab forbidding it for

which punishment is imposed upon conviction. There are lots of different kinds of crime.

• Can you think of some different types of crime?

• Forensic scientist – scientist who solves problems such as what caused an accident or who committed a crime

What I think now…• Write down your current answer to the question –

• “How can science solve crime?”

• We’ll revisit your answer at the end of the unit, so make sure you keep it safe and don’t lose or swap books!

Crime scenes• After a crime has occurred, police and forensic scientists

investigate the crime scene and gather evidence.

• Evidence is objects found at a crime scene or statements by witnesses to a crime.

• Witness statements need to be treated very carefully as people’s memories can be affected by events or time. They have misheard a conversation or they may have heard the information from someone else

Whispers

• What to do: • Get everyone in the class to stand in one straight line.

The teacher will whisper some information into the ear of the person standing at the front of the line. This person will then whisper the information into the ear of the next person and so on. When the information gets to the end of the line, compare the initial whisper with the final whisper.

Whispers – What did you discover?

• 1. What sentence did the teacher whisper?• 2. What was the whispered sentence at the end?• 3. If there was a difference, explain why the difference

occurred between the two sentences.• 4. Why do police need to treat people’s memory of an event

or conversation very carefully?

Being an eyewitness

• An eyewitness is someone who witnesses a crime. Sometimes the crime happens so quickly and so unexpectedly that you do not have time to see what is going on, let alone take it in. Several eyewitnesses wh0o witness the same crime sometimes have very different stories to tell.

Being an eyewitness• Look at the image on the following slide for 10 seconds, then

try and answer the questions that follow.

Being an eyewitness

• Which window has been smashed?• What colour are the computers?• What is the colour of the coat hanging on the back

of the chair?• What is the colour of the soft drink can next to the

computer?• What is written on the note lying on the keyboard?• How many computers can you see?• How many students are looking through the

broken window and are they male or female?

Being an eyewitness – Look again

Being an eyewitness

• How many questions did you get right? Compare your results with those of the rest of the class.

• How observant were you? How good an eyewitness would you make?

• Did anyone in the class answer all the questions correctly?

Being an eyewitness

• How do you think you would perform on these questions if you had looked at the picture for ten seconds yesterday? Use your response to explain why police ask everyone that was near the scene of a crime what they saw as soon as possible after the crime has taken place.

• Why is it best to have as many eyewitnesses as possible?

Reflection

• What are you looking forward to in this unit?• How did you go in the pre-quiz? Write down your

score.• Write down one goal for this unit. How can you

attempt to reach that goal?

Lesson 2 – Forensic Scientists and Collecting evidenceExpected learning: to learn about some of the different types of physical evidence that can be used to solve crime

Enter the forensic scientist• The principal by which forensic scientists work by is that every

contact leaves a trace or evidence

• There are many kinds of evidence that can be left behind at crime scenes

Mock Crime Scene: http://www.masss.gov

What evidence would you collect?

Fingerprints• When we touch objects we leave fingerprints, the pattern of

tiny ridges in the skin on the tips of our fingers• This is because small amounts of perspiration and oil are on

our skin at all times. This small amount of moisture deposits in the pattern of the ridges when we touch something

Fingerprints• Amazingly, every

person’s fingerprints are unique – even identical twins have different fingerprints. This makes fingerprints a vital piece of evidence because they can place a suspect at the scene of a crime

Fingerprints• When fingerprints are left at the scene of a crime, fine powder

is dusted softly onto them so that the powder sticks to the traces of sweat and oil. Photos are taken and then the prints are lifted off the surface with tape

Fingerprints• Fingerprints found at crime scenes are checked using the

Automatic Fingerprint Identification System (AFIS) in case the culprits fingerprints are already on file. This computerised system very quickly compares crime scene fingerprints with a computer database of the fingerprints of known offenders

Taking your own prints• Roll your fingers one at a time across the inkpad

• Carefully roll your finger across the Fingerprint worksheet in each box

• Wipe each finger clean after making each fingerprint

• Compare your prints with those of other students in the class

• Complete the questions on the fingerprint worksheet

• Make sure you keep your fingerprint profile as you will need this in a future lesson

Fingerprints in court• Fingerprints have not always

been used as evidence in court. When they were first used, the defence lawyers objected because the have never been used before. The judge sent he fingerprint expert out of the room and the jury were fingerprinted. The expert was able to accurately lift a print of a juror off an object and correctly name the juror who had put it there. The judge allowed the fingerprints to be used as evidence

WOW – Lip Prints• The prints left by someone’s lips on a glass or cup can also be

used to help identify who was present when a crime was committed. If the person was wearing lip gloss or lipstick, the brand can be identified with chemical testing.

Questions• Answer the questions on the following slide

• Read through the information in Science Edge 2 Chapter 1 pages 2, 3, 4, 6, 7, 8, 9, 10 and answer the questions on page 34

• Add any new definitions to your code breaker sheet

• During this time you will conference with your teacher for your next progress report.

Questions…• 1. Explain why we leave fingerprints on things.• 2. Describe how a fingerprint can be obtained from an object

such as a glass

• Handout Questions:• 1-5 and 7

Reflection• What were the most common fingerprint patterns in our

class? • List two reasons why the role of a forensic scientist is

important

Lesson 3 – Collecting evidenceExpected Learning – to learn about some of the different types of physical evidence that can be used to solve crime

Imprints• A note pad was found at a crime scene. There was nothing

written on it – or was there?

• One simple way to reveal what was written on the previous page before it was removed from the notepad is to rub a very soft pencil over the top piece of paper.

• This works because when we write on paper we put a lot of pressure on it with the end of the pen or pencil. The pressure can be transferred to the sheet below.

• Even though the pressure on this second page is not as great, it can leave slight indentations in the paper. There are called imprints

Imprint Activity• You need – notepad, pen, soft pencil

• What to do:• Write a secret message on the top sheet of the notepad using

a pen. Do not let your partner see what you write!• Remove the top sheet and give the next sheet to your partner• Get your partner to gently shade over the imprint area with

the soft pencil. Can he or she read the message? • Switch and do the same to discover your partner’s secret

message• Stick the original message and the imprint into your workbook

Imprint Activity• What did you discover?• 1. What was the message that your partner wrote?• 2. How easy was it to work out the message?• 3. How might an imprint found at a crime scene help identify

the person who committed the crime?

Fibres - Hairs & Fabric • Fibres from fabric and hair can be another type of evidence

that can place a suspect at the scene of a crime.• The fibres may be found of the floor, on clothes or perhaps

caught on a piece of furniture

Hair• Hair is made of a protein called keratin • The shape and texture of hair is influenced heavily by genes• Hair colour is mostly the result of pigments, which are

chemical compounds that reflect certain wavelengths on visible light

• In order to test hair for DNA (we’ll learn more about DNA in a few lessons time), the root must be present

• Different characteristics of hair can help us identify what species that hair has come from

Hair Structure

Hair is composed of three principal parts:

The structure of hair has been compared to that of a pencil with the medulla being the lead, the cortex being the wood and the cuticle being the paint on the outside.

http://library.thinkquest.org/04oct/00206/lesson.htm#t_hair

Cuticle – outer coating composed of overlapping scales

Cortex – protein-rich structure around the medulla that contains pigment

Medulla – central core(may be absent)

Fabric Fibres• A fibre is the smallest unit of a textile material• It is much longer than its diameter• Matching unique fibres found on the clothing of a victim to

fibres on a suspect’s clothing can be very helpful in an investigation, whereas the matching of common fibres such as white cotton or blue denim would be less useful

• The discovery of multiple fibres transferred between the victim and suspect increases the likelihood that these two individuals had contact.

Analysing Fibres• Different kinds of

microscopes are used to identify and compare fibres. Microscopes can identify if a hair is from a person or an animal, if a fibre is from carpet or clothing, if the fibre has been cut and, if so, by what type of cutting tool. Forensic scientists can even match up fibres found at the scene of the crime with those from a suspect’s house

Analysing Fibres Prac• You will have a chance to examine some different hair and

fibre samples.

• If you do not wish to look at your own hair, you can use another sample

Reflection• What could a cat hair found on a suspect and at a crime scene

suggest?• How might imprints be helpful to the police when

investigating crime?

Lesson 4 – Collecting evidenceExpected Learning: To learn how to lift fingerprints off objects and determine who touched them

Paper Chromatography• Inks in different brands of pen are made by mixing different

pigments together• A separation technique called paper chromatography can help

identify what pen some writing came from

• Paper chromatography relies on the fact that different pigments climb up a strip of wet paper at different speeds

• We won’t do this prac in class, but you will have the chance to do paper chromatography on your science matrix if you wish

Fingerprint Prac – Science Edge 2 page 22-23• You will try lifting fingerprints off several objects today• First, locate your fingerprints you took in lesson 2• Begin writing up the prac in your book (this will go towards

your “Science at work” VELS mark)• Aim – in OWN words• For materials and method you can write “refer to Science Edge 2,

p. 22. Carefully follow the instructions on your prac handout• Results -stick the fingerprint you lifted into your report• Discussion – questions from book except no. 8 • Conclusion – Who touched the object you tested?

If time..• Can discuss some of the answers to discussion questions as a

class

Reflection• Explain how finding a suspect’s fingerprint at a crime scene

may help solve a crime.

Lesson 5 – DNA FingerprintsExpected learning: To learn about our unique genetic material DNA and the role that this has in solving crime

DNA• Prior Knowledge QU’s:

• Put your hand up if you have heard of DNA before.• Where have you heard it?

• Keep your hand up if you think you know what it is.• What do you think it is?

• Can anyone tell me what the D, N and A stand for?

DNA• DNA is deoxyribonucleic acid• DNA is our genetic material or

genetic code• It is found in the nucleus of

each of our cells• It is found on structures called

chromosomes• The information is stored in

codes called genes• This genetic code determines

our features (eg. Eye colour)

DNA• DNA is inherited from our parents

• We get 50% of our genetic material from our mum and 50% of our genetic material from our dad.

• This becomes useful when identifying DNA samples (we’ll look at this more next lesson)

DNA

• DNA is a double-stranded helix shaped molecule that contains nitrogen-containing substances called bases.

DNA• There are four types of bases:

• adenine (A)• guanine (G)• thymine (T)• cytosine (C)

• Bases on one strand bond with bases on the opposite strand

• Base A will bond only with T

• Base C will bond only with G

DNA• The strands are made from sugar and phosphorous

Genes• A gene is section of this DNA code. Each gene codes for one

characteristic

chromosomes

• Made up of DNA and proteins

• An organism of a particular species always has the same number of chromosomes (e.g. humans have 23 pairs)

Centromere

chromosomes

HUMAN FEMALE HUMAN MALE

DNA at crime scene• It is quiet easy to leave DNA behind at a crime scene

• As DNA is found in all of our body cells (except RED blood cells), it can be left at crime scenes in many ways – in white blood cells, semen, cheek cells found in saliva, skin cells and hair roots.

How is DNA used as evidence?• Each person’s DNA is different from other people (except identical twins).

• DNA collected from a crime scene can either link a suspect to the evidence or eliminate a suspect, similar to the use of fingerprints.

• DNA can identify a victim through DNA from relatives, even when no body can be found.

• DNA can link crime scenes together by linking the same perpetrator to different scenes locally, statewide, and across the nation.

• DNA can place an individual at a crime scene, in a home, or in a room where the suspect claimed not to have been.

• DNA can refute a claim of self-defense and put a weapon in the suspect's hand.

• It can change a story from an alibi to one of consent.

DNA Strand Image & information : http://www.dna.gov/audiences/investigators/know/

What factors affect DNA evidence?• Several factors can affect the DNA left at a crime scene,

such as environmental factors (e.g., heat, sunlight, moisture, bacteria, and mold). Therefore, not all DNA evidence will result in a usable DNA profile. Further, DNA testing cannot identify when the suspect was at the crime scene or for how long.

Make a model• Recap of structure:• http://www.youtube.com/watch?v=qy8dk5iS1f0

• Use materials provided by your teacher to construct a DNA model

• Take a photo of your model if you like

• Show your model to at least 3 other students and look at the models of at least 3 other students

Reflection• What is DNA?• Why could the discovery of DNA evidence at a crime scene be

crucial to solving a crime?

Lesson 6 – DNA EvidenceExpected Learning: To compare DNA profiles and determine which murder suspect committed the crime

Re-cap of last lesson• What is DNA?

• What are some of the ways that DNA can be left at crime scenes?

• True or False: the DNA in a man’s blood is the same as the DNA in his skin cells and saliva?

Using DNA from crime scenes• http://www.youtube.com/watch?v=dXYztbkMXwU

DNA Profiles• When forensic scientists find a DNA sample at a crime scene,

they put it through a process to gain a DNA fingerprint

DNA Fingerprints• These DNA fingerprints can be used to match a suspect’s DNA

to a crime scene, identify victims and also determine if two people are related

Task• Complete the DNA Murder worksheet

Blood basics

What makes up our blood?• RED BLOOD CELLS (Erythrocytes) – The most abundant

cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells.

• WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens.

• PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection.

• PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood.

Blood Facts

The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight.

Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy.

There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell.

http://www.bloodbankofalaska.org/about_blood/index.html

Genetics of Blood Types

• Your blood type is established before you are BORN, by specific GENES inherited from your parents.

• You inherit one gene from your MOTHER and one from your FATHER.

• These genes determine your blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of your red blood cells.

What are blood types?

http://learn.genetics.utah.edu/units/basics/blood/types.cfm

There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations.

Blood Types

AA or AO = Type ABB or BO = Type B

OO = Type OAB = Type AB

What are blood types?

http://learn.genetics.utah.edu/units/basics/blood/types.cfm

There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations.

Blood Types

AA or AO = Type ABB or BO = Type B

OO = Type OAB = Type AB

What are blood types?

http://learn.genetics.utah.edu/units/basics/blood/types.cfm

There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations.

Blood Types

AA or AO = Type ABB or BO = Type B

OO = Type OAB = Type AB

Blood Evidence• Blood samples – Can be analyzed to determine blood

type and DNA, which can be matched to possible suspects.

• Blood droplets – Can be analyzed to give clues to the location of a crime, movement of a victim, and type of weapon.

• Blood spatter – Can be analyzed to determine patterns that give investigators clues to how a crime might have happened.

Microscopic Views

Bird Blood

Cat Blood

Dog Blood

Fish Blood

Frog Blood

Snake BloodHuman Blood

Horse Blood

Reflection• What is the most common blood type? • Do you know your own blood type? • List one reason why the discovery of DNA fingerprinting

techniques has been of benefit to society.

Lesson 7 – Why do people commit crime?

Lesson 8 – Kids and CrimeExpected Learning: to think about the age of people committing crime and the sort of punishment involved for kids

SBS Insight• Watch the episode of Insight titled “Kids and Crime”• http://

www.sbs.com.au/insight/episode/watchonline/47/Kids-and-Crime

• After it is finished, discuss as a class the following questions:• Who is to blame when children under 10 commit violent crimes?• What about when teenagers commit crime?• Do you believe that teens should be sent to juvenile justice

centres?• Do you see much violence amongst your peers either at school or

on weekends? If yes, what kind of violence and why do you think it is occurring?

• Do teenagers think about the consequences of fights, or just see them as something to brag about?

Reflection• Choose two of the questions we discussed to answer in your

book as reflection questions:

• Who is to blame when children under 10 commit violent crimes?• What about when teenagers commit crime?• Do you believe that teens should be sent to juvenile justice

centres?• Do you see much violence amongst your peers either at school or

on weekends? If yes, what kind of violence and why do you think it is occurring?

• Do teenagers think about the consequences of fights, or just see them as something to brag about?

Reflection 2:• Answer again:

• “How can science solve crime?” Compare your answer to your initial answer at the beginning of the unit.