ScienceIQ.com

Facts About Angina

Angina is a recurring pain or discomfort in the chest that happens when some part of the heart does not receive enough blood. It is a common symptom of coronary heart disease (CHD), which occurs when vessels that carry blood to the heart become narrowed and blocked due to atherosclerosis Angina feels like a pressing or squeezing pain, usually in ...

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FactsAboutAngina
Geology

The San Andreas Fault

Scientists have learned that the Earth's crust is fractured into a series of 'plates' that have been moving very slowly over the Earth's surface for millions of years. Two of these moving plates meet ... Continue reading

TheSanAndreasFault
Biology

Tea Time!

Did you know that a disease of coffee plantations made the British tea drinkers? In the 1700s Britain had many coffeehouses that served as popular social gathering places to discuss current events and ... Continue reading

TeaTime
Medicine

What Is Botulism?

Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum. There are three main kinds of botulism. Foodborne botulism is caused ... Continue reading

WhatIsBotulism
Medicine

The Plague

Plague is an infectious disease caused by the bacterium Yersinia pestis. The bacterium is found mainly in rodents, particularly rats, and in the fleas that feed on them. Other animals and humans ... Continue reading

ThePlague

What Makes a Frisbee Fly?

FrisbeeIf you have ever been to the park or the beach, you've probably seen one of these plastic discs flying through the air. We're not talking about a UFO, we're talking about the Frisbee, more commonly known as the flying disc. What makes a Frisbee fly? Just like a bird's wing or the wing of an airplane, shape plays a large part in influencing the flying ability of the Frisbee.

If we take a look at the Frisbee from the side, we can see that the rounded edges of the Frisbee look similar to the front edge of an aircraft wing. We know that the curved upper surface of the wing is what generates (causes) lift. The same principle applies to the Frisbee. As air passes over the curved upper surface of the Frisbee it speeds up, creating a low pressure region on top of the Frisbee. Below the Frisbee, air passes more slowly, creating a high pressure region. The difference in pressure gives the Frisbee lift. The shape of the Frisbee generates lift, but it needs more than that for flight.

Try throwing a Frisbee without spinning it. Notice how it wobbles and tumbles. The shape of the Frisbee may be generating lift, but the Frisbee is unstable. It cannot stay upright and eventually stalls (falls). All flying things must have something that makes them stable during flight; airplanes and birds have tails, rockets have fins. For a Frisbee, it is the spinning motion generated from the Frisbee throw that stabilizes the Frisbee as it flies.