Page 88 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

Why are bicycles

much more stable

when moving?

here is no definitive explanation behind a moving bike’s
T uncanny ability to stay upright. Experts agree that it is
linked to bikes’ ability to steer into a fall and right themselves,
with even riderless bikes able to recover from a sideways
push. For a long time, it was believed that the wheels created
stability through the gyroscopic effect: the tendency for a
spinning object to resist movement in certain directions.
A second idea was that the direction of travel aligns the bikes
wheels a bit like when pushing a shopping cart. Researchers,
however, disproved these theories in 2011 by building a bike
which negated both effects. A pair of counter-rotating wheels
cancelled out the gyroscopic effect and the steering axis lay
behind the front wheels, yet the moving bike was still stable.
The research team concluded that although both effects may
have an impact, neither were vital to a bike’s stability.

Are we able to digest sweetcorn?

lthough unchewed sweetcorn appears to
A be able to pass through the digestive
system completely unchanged, it has actually
been partly digested. The inside of the corn
kernel is made up mostly of starch, and is
easily digestible, but the outside is made from
tough plant fibre called cellulose. Humans lack
the digestive enzymes required to break down
cellulose, so if you don’t chew your sweetcorn
properly it will pass through your digestive
What makes system whole. Digestive enzymes are able to
diffuse across the membrane, breaking down
my joints crack some of the starch inside and releasing sugar
molecules into the gut, but from the outside it
so often? looks almost exactly the same.

here are a few different reasons why
T your joints may crack. Joints are Why do we have
lubricated by a fluid called synovial fluid,
which contains gases like carbon dioxide, blood types?
nitrogen and oxygen. When you move the
joint, gas bubbles are quickly released and he short answer is that we still don’t know.
make a popping sound. Popping noises may T There an incredible 33 different blood-group
also come from tendons and ligaments systems in humans, but the most commonly talked
moving or tightening as the joint moves. about is the A, B, O system, which has four types.
Sometimes joints crack more often after Depending on your genetics, your red blood cells are
surgery or if you have arthritis, which can coated in A antigens, B antigens, both A and B
cause rough joint surfaces and worn antigens, or neither (in which case you are blood
cartilage. Despite what you may have heard, type O). We know these factors affect blood
cracking joints don’t indicate a problem transfusion, but the real reason behind different
unless they’re also accompanied by pain, blood types seems to be related to the spread of
swelling, or loss of function or motion. infection; for example, people with blood type O are
Purposely cracking your knuckles, however, more susceptible to bubonic plague, but are better
may lead to swollen joints and a weaker grip. protected against malaria.

88 How It Works