John Clayton
Did you ever wonder why they can take your blood pressure by
measuring it on your arm or your leg? Blood pressure is the
pressure the heart puts on your blood, so how can they measure it
on your arm? The answer to this question is rooted in the nature
of liquids and a famous law of physics called Pascal's law. This
law says "pressure exerted on a fluid is distributed
throughout the fluid." What that means is that when the
heart puts pressure on your blood, that pressure is the same
everywhere in your body (if you're laying down). This is also the
reason why when you put pressure on the brake pedal in your car,
the pressure is distributed to the wheels, a long way from where
your foot is.
All of this would not work well however, if blood was like
air. When you put pressure on air it compresses and becomes more
dense. This is why air rushes out of your tire when you get a
hole in the tire or out of a balloon when it bursts. The
molecular structure of liquids is such that they compress very
little. When your heart pressurizes your blood, that pressure is
the same instantly everywhere in your body. Your brain does not
have to wait to get blood, and the blood comes smoothly bathing
cells in the vital soup of oxygen and nutrients that keeps them
healthy.
Psalm 139:14 says "I will praise the Lord, for I am
fearfully and wonderfully made." Not only are we made
fearfully and wonderfully, but the materials that make up our
bodies have carefully designed characteristics which make them
ideal for the uses they serve in our bodies.
This article taken from: Does God Exist?, Jan/Feb 1999.
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