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Flashcards in Fair testing and forensics Deck (40)
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what is a fair test

a fair test is when one factor is changed at a time and all other variable remain the same.


independent variable

what is the thing that will be different each time you dot the experiment


dependent variable + example

what are you measuring?


How to ensure accuracy and reliability in investigations

is it valid?- does the info relate to the problem/ question being investigated
is it reliable? .gov, .org, .edu etc.


Data table rules

use ruler and pencil
table columns
write units in heading boxes only
left most column for independent variable
include average column


describe the scientific method

A process for experimentation that is used to explore observations and answer questions.


goal of the scientific method

to discover cause and effect relationships by asking questions
carefully gathering and examining evidence
using all available info to see if it can be combined to make a logical answer


what is the scientific method

ask a question
do background research
construct a hypothesis
test with experiment
procedure working
yes or no= carefully check all steps and set up go back to test with experiment
if yes analyse data and draw conclusions
results align partially or not at all with hypothesis= ask a new question experiment again return to construct a hypothesis or
results align with hypothesis
if results align with hypothesis communicate results


what are trends

Trends are general directions of data


patterns in data

after data is collected it can be analysed by looking for trends, patterns and relationships


product claims- the role of science

do to false advertising being so common science can be used to evaluate the claims made by companies. To test if something is valid scientific evidence needs to support these claims to help us push through the fake claims.


what is forensics

forensics is a tool that uses science to help solve crimes by determining who committed them and how


forensic scientists

these are experts in the application of scientific methods and techniques to matters under investigation by a court of law.
They examine evidence using the scientific method, make predictions, test them and draw conclusions



the available body, facts or info indicating whether a proposition is true valid or false



a form of trace evidence that can be transferred from a fabric source such as carpet, clothing, bed or furniture


Dna profiling

technology used in crime scene identification
DNA profiling can prove a persons identity except in the case of identical twins
DNA sequences can be made visible as X-ray lines that look like a bar code. These 'bar codes' give a unique pattern for every person


Facial recognition technologies

is used to identify individuals using facial characteristics
it is the least intrusive and fastest biometric technology
used to know ones true identity


when is facial recognition technology important

crossing an international border
claiming monet from the government, institutions and or individuals
when gaining access to sensitive files


What facial recognition technology cane be used to identify fraud

biometric facial recognition


biometric facial recognition

the software allows a computer to identify people by their faces. It measures the position of your facial features and compares them with those of photographs on pre existing files.
It is used at airports


Fingerprint scans

typically works by first recording fingerprint scans of individuals. These scans are saved within a database.
It utilises an electrical current. The ridges of your skin are electrically non conductive whereas the valleys of your fingertips are conductive. When touching a fingerprint sensor it measures the minutest differences in conductivity caused by the presence of ridges.


fingerprint inks

Before the digital scanning technologies fingerprinting was done using ink and a card. A persons finger is cleaned using alcohol to remove any sweat and is then dried. The person rolls their finger in ink. Then makes an impression on card by rolling each finger from one side of the fingernail to the other.



the iris is the coloured rings of muscle in the eye that controls the size of the pupil
The iris has patterns and colouring that is extremely complex
each person has a unique pattern and each eye is different making it a better method of identification than a fingerprint.


iris scans

first stage- enrolment system sees you for the first time and learns to recognise you. A person stands in front of a camera and has their eyes digitally photographed in ordinary light and infrared. The photos are analyses by the computer where unnecessary details are removed and identifies around 240 unique features. These features are turned into an iris code that is stored.



retina is the rear of the eye and its pattern of blood vessels is even better than the iris in proof of identity.


retina scans

It is performed by casting an unperceived beam of low energy infrared light into a persons eye as they look through the scanners eyepiece
this bam of light traces a standardised path of the retina


contact evidence + example

evidence that results from physical contact


trace evidence + examples

tiny fragments of physical evidence
hairs, fibres



a form of trace evidence that can come from the criminals and appear a a crime scene



it is created when two objects come in contact with enough force to cause an impression