ScienceIQ.com

Did You Smell Something?

There's not a moment of our lives when smells -- or, more precisely, odor molecules -- aren't impacting our brain. It's been estimated that it takes at least 40 molecules of a given odor for us to be aware of a smell. But each one of our receptor cells can fire in response to as little as a single odor molecule wafting through the air. So even if ...

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Smell
Medicine

What Is a Bruise?

A bruise is a deposit of blood under the skin. It flows from tiny capillaries that break when you bump your shin on the furniture or take the batter's pop fly in the eye. The injury starts out looking ... Continue reading

WhatIsaBruise
Astronomy

Ancient Planet in a Globular Cluster Core

Long before our Sun and Earth ever existed, a Jupiter-sized planet formed around a sun-like star. Now, 13 billion years later, NASA's Hubble Space Telescope has precisely measured the mass of this ... Continue reading

GlobularClusterCore
Astronomy

The Real Lord of the Rings

Why is Saturn the only planet with bright, easily seen rings? Saturn is not the only planet in our solar system with rings. Jupiter, Neptune and Uranus all have rings. Jupiter's rings are much smaller ... Continue reading

Saturn
Biology

Grizzly Bear, (Ursus arctos horribilis)

A symbol of America's wildlands, the grizzly or brown bear is one of the largest North American land mammals. The grizzly bear's historic range covered much of North America from the mid-plains ... Continue reading

GrizzlyBear

Many Happy Returns!

ManyHappyReturnsThe boomerang is a bent or angular throwing club with the characteristics of a multi-winged airfoil. When properly launched, the boomerang returns to the thrower. Although the boomerang is often thought of as a weapon, the device has primarily been used in hunting and served as a recreational toy. The boomerang consists of a leading wing and a trailing wing connected at the elbow. Each wing has the typical cross section of an airfoil. Therefore, each wing has a leading and trailing edge arranged so the leading edge strikes the air first as the boomerang rotates. Due to this configuration, there are right-handed and left-handed boomerangs. A left-handed boomerang is simply a mirror image of the right-handed boomerang. The typical angle between the wings is 105 degrees to 110 degrees.

As the boomerang flies through the air, each wing produces lift. Due to the shape of the boomerang a pressure differential exists between the lower and upper surface (on each wing) which creates aerodynamic lift. A boomerang is thrown with a spin which has two effects on the boomerang as it travels through the air: a stabilizing force known as gyroscopic stability and the development of a curved flight path. The turning force imposed on the boomerang comes from the unequal air speed of the spinning wings. For a stationary, spinning boomerang, both wings would produce the same amount of lift. Now applying the same spinning boomerang with a forward velocity and the speed of the air traveling over the wings differs. Thus, the forward moving wing experiences more lift than the retreating wing. The net result is a force which turns the boomerang.