Page 89 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

Science

Why do

reflections

appear reversed

in the mirror?

irrors appear to reverse things from
Mleft to right because of our
perceptions. Our bodies are roughly
symmetrical, so the reflection of your left
hand looks just like your right hand. For this
reason, we tend to assume that mirrors
reverse left and right. But if you hold up an
asymmetric object in front of a mirror, for
example a saucepan, left and right are not
reversed. The right-hand side of the saucepan What causes
(for instance the handle) is still on the right,
and the left-hand side is reflected on the left. indigestion?
Instead, a mirror inverts front and back.
ndigestion (also known as dyspepsia) is
I a pain in your stomach after eating. It’s
caused by the acid in your stomach coming
into contact with the lining of the digestive
system (the mucosa). This lining is sensitive
and can be irritated by the harsh acid,
which breaks it down and can also cause it
to swell, leading to the discomfort you feel.
Indigestion is most often triggered by
eating, but can also be caused by smoking,
drinking, stress or certain medications. It is
often treated with antacids, which
neutralise the acid made by your stomach
and helps relieve the pain.

Why do voices

change during

puberty?

How does acupuncture work? e speak by pushing air through

Wtwo elastic vocal cords attached
hether acupuncture really works is a needles in nontraditional places, or to cartilage in a structure known as the
W matter still debated in medical and pretending to insert them while in reality just larynx, or voice box. The tissue in the
scientific communities. This is because holding the needles against the skin. In these voice box responds to the male sex
designing medical trials to test acupuncture tests, acupuncture was found to be more hormone testosterone, so when levels
is challenging. A good trial would pit the effective than the sham and the placebo for rise during puberty it triggers
treatment against a harmless placebo, and relieving pain associated with headaches, thickening and growth. Just like the
neither the patients nor the doctors would osteoarthritis, back and neck pain, but for thicker strings on a guitar make a lower
be aware of which they were receiving or other conditions such as rheumatoid sound when they vibrate, the
administering. In the case of acupuncture, arthritis, and shoulder pain, there was no thickening of the vocal cords can alter
this is near impossible. convincing evidence that it works. One idea the pitch of a boy’s voice by up to
In order to get around this, the trials use is that it might stimulate the production of an octave.
‘sham acupuncture’, either inserting the endorphins, the body’s natural painkillers.

How It Works 89