Edible/Inedible Experiments Archive
Taking a pulse
Area of Science: Biological Sciences
Meant for Grade 4-6 (age 8-10).
This experiment is inedible.
An adult need not be present.
Take your pulse at mutliple sites. Relate the pulse to heartbeat.
Nothing - free fingers.. a diagram of the body and a stethoscope
may be helpful.
When taking the carotid pulse in the neck, be certain to take one
side at a time!
How to do the experiment:
Try taking your pulse at the following sites (see picture)
Radial Pulse: This is probably what we're most familiar
with when visiting the doctor's office. Take two fingers, preferably
the 2nd and 3rd finger, and place them in the groove in the wrist
that lies beneath the thumb. Move your fingers back and forth gently
until you can feel a slight pusation - this is the pulse of the
radial artery which delivers blood to the hand. Don't press
too hard, or else you'll just feel the blood flowing through your
fingers! You can even use your thumb.
Carotid Pulse: The carotid arteries supply blood to the
head and neck. You can feel the pulse of the common carotid
artery by taking the same two finger and running them alongside
the outer edge of your trachea (windpipe). This pulse may be easier
to find that of the radial artery. Since the carotid arteries supply a lot of the
blood to the brain, it's important not to press on both of them at
the same time!
femoral pulse: The femoral atery carries blood
to parts of the leg. Aside from the carotid artery, it
is another common site to check for a pulse in an emergency
situation. Think of an imaginary line
running from your hip to the groin. The approximate superficial
location of the femoral artery lies 2/3 of the way in from the hip.
Admin note: the other following sites can also be tried:
- facial artery: Gently run a finger along the lower edge
of the jaw bone. Just beyond the 'chin' on either side, you might
be able to feel the pulse of the facial artery.
- brachial artery: Flex your bicpes muscle. Press your
thumb or a few fingers into the groove created between the biceps
and other muscles, approximately 5cm from the armpit. You should
be able to feel the pulse of the brachial artery. This is the major
artery supplying blood to the arms.
- Abdominal aorta: Very thin individuals may be able to note
a slight pulsation beneath the stomach when lying down in a relaxed
position. This pulsation is caused by the abdominal aorta, the
continuation of the aorta from the heart. At the level of the umbilicus
(belly button), the aorta splits into the left and right common iliac
ateries which deliver blood to the legs.
- Popliteal atery: This artery lies behind the
knee. Bend your knee slightly and feel in the soft area behind
The pulse represents the beating of the heart, specifically the
ejection of blood from the left ventricle to the general
circulation of the body. The ventricles (right and left) have
two phases: diastole or the time when the ventricles
'rest' so they can fill
with blood, and systole, the time when the ventricles
contract to send blood either to the lungs (from the right side
of the heart), or to the rest of the body (from the left side of
the heart). Blood from the left side of the heart first enters the
aorta, the largest artery in the body. The aorta branches
into smaller arteries which carry blood to all part of the body.
The pulse represents the variation in blood pressure from
diastole to systole. During diastole blood
pressure falls, but increases after systole as the heart pumps
more blood into the arteries. You feel this difference when taking
your pulse. Doctors use a device called a sphygmomanometer
(blood pressure cuff) to measure the systolic and diastolic
blood pressures. The average adult has a systolic blood pressure
~120-150 mm mercury, an average diastolic blood pressure ~80
mm mercury, and an average pulse of 72 beats/minute.
If you have a stethoscope try listening to your heart
while taking your pulse. Your heart produces two sounds, often
called 'lub' and 'dub.' The second,'dub' sound coincides with the
ejection of blood from the ventricles In actuality, the sound is produced by the
aortic and pulmonic valves closing behind the ejected blood. The aortic valve
opens from the left ventricle into the aorta; the pulmonic valve from the
right ventricle into the pulmonary artery.
When does the pulse occur with respect to the second heart sound? the first
The human heart, an
Experiment submitted on Sun Mar 2 21:58:57 1997 by:
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