Ashley Yaffe
10/29
Science Fair Lab Report
Title:
What is the Effect of a lie on the Blood Pressure?
Introduction - Purpose:
The purpose of this experiment was to find out how accurate the polygraph test is for
determining a lie. This experiment is also helpful for anyone who is thinking about becoming a
lawyer or a criminal investigator because this project will help the lawyer or criminal
investigator to notice different behaviors when the witnesses or criminals are lying and this
experiment will help lawyers to understand the polygraph that is used by criminal investigators.
The purpose of this experiment is also to learn why some criminals do not get arrested who have
taken the polygraph test.
Introduction - Background Research:
A polygraph is an instrument for recording blood pressure, pulse rate, and respiration of a
human.
A pneumograph tube is fastened around the subject’s chest, and a blood pressure–pulse
cuff is strapped around the arm. Pens record impulses on moving graph paper driven by a small
electric motor. The polygraph has been used in police investigation since 1924. Due to the stress
of lying, means that more oxygen is needed for the body which increases breathing rate and
blood pressure.
The abbreviation mm Hg means millimeters of mercury. Systolic blood pressure
is the first top number that is measured. Systolic is the amount of pressure that is caused by
heart
contracting and pushing out blood when the heart beats. Diastolic blood pressure is the second
bottom number that is measured. Diastolic blood pressure is the amount of pressure when your
heart relaxes and fills with blood while the heart is resting between beats. A normal blood
pressure reading for systolic is less than 120 and a diastolic that is less than 80 mm Hg.
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- Fall '17
- Mr. Cheung
- Chemistry, Science, pH
