Fair testing and forensics Flashcards

(40 cards)

1
Q

what is a fair test

A

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

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2
Q

independent variable

A

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

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3
Q

dependent variable + example

A

what are you measuring?

temperature

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4
Q

How to ensure accuracy and reliability in investigations

A

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

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5
Q

Data table rules

A
label
use ruler and pencil
table columns
write units in heading boxes only
left most column for independent variable
include average column
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6
Q

describe the scientific method

A

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

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7
Q

goal of the scientific method

A

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

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8
Q

what is the scientific method

A

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

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9
Q

what are trends

A

Trends are general directions of data

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10
Q

patterns in data

A

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

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11
Q

product claims- the role of science

A

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.

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12
Q

what is forensics

A

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

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13
Q

forensic scientists

A

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

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14
Q

evidence

A

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

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15
Q

fibres

A

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

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16
Q

Dna profiling

A

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

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17
Q

Facial recognition technologies

A

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

18
Q

when is facial recognition technology important

A

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

19
Q

What facial recognition technology cane be used to identify fraud

A

biometric facial recognition

20
Q

biometric facial recognition

A

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

21
Q

Fingerprint scans

A

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.

22
Q

fingerprint inks

A

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.

23
Q

Iris

A

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.

24
Q

iris scans

A

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.

25
retina
retina is the rear of the eye and its pattern of blood vessels is even better than the iris in proof of identity.
26
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
27
contact evidence + example
evidence that results from physical contact | finerprints
28
trace evidence + examples
tiny fragments of physical evidence | hairs, fibres
29
hairs
a form of trace evidence that can come from the criminals and appear a a crime scene
30
impressions
it is created when two objects come in contact with enough force to cause an impression
31
forged documents
criminals sometimes use fake signatures and documents to get what they want forensics can help determine if a signature/ document is real and/ or who wrote something
32
handwriting
``` things to detect: layout the slant the pressure whether they underline their signature rounded letters ```
33
papers and inks
paper differs in texture, absorbencies, presence of watermark and weight. These affect the way an ink is spread and absorbed as well ad the way each individual letter appears.
34
chromatography
uses a solvent such a s water or alcohol to dissolve and separate an ink into its component pigments in this way the ink can be used to match a signature, letter or printed, can be matched with a suspects pen or printer
35
the impacts of forensic science on society
countless convictions have been based heavily upon forensic evidence and testimony dna fingerprinting has led to more conviction especially in cases of sexual assault ( body fluids can be matched with a suspects dna) the exonerations of many former criminals cold cases have been reopened and solved an increase in the popularity of books and shows based on the field.
36
what is leotards exchange principal in forensics
it states that the perpetrator of a crime will bring something into the crime scene and with something from it, both can be used in forensic evidence
37
what evidence can a criminal leave
fingerprints, footprints, hair, skin, blood, body fluids, pieces of clothing etc.
38
evidence the criminal takes away + examples
when the criminal comes into contact with anything at a crime scene a criminal takes part of that scene with them whether its hair or any other type of trace evidence
39
how does biofacial recognition work
face recognition algorithms identify facial features by extracting landmarks, or features, from an image of the subject's face. For example, an algorithm may analyze the relative position, size, and/or shape of the eyes, nose, cheekbones, and jaw. ... A probe image is then compared with the face data.
40
where does a voltmeter and ammetre go in a circuit
A voltmeter is connected in parallel with a device to measure its voltage, while an ammeter is connected in series with a device to measure its current.