A- A A+
Log in

Login form

You need to sign in to those awesome features
or use your account
Remember me
Power by Joomla Templates - BowThemes

NHA Banner

 Notices on Our Content: Member Protected Content,  Walk Acess Restrictions may apply.

up    We collected weblinks for our Custom Google Search above to help you target searches to nature websites we like. Submit your favourite nature website - contact us.
Internet Explorer users need to be on Version 10+.


There is a famous photograph of construction workers on the Rockefeller Centre in New York sitting in a row along a narrow girder, hundreds of metres above the street, having a relaxing lunch break without the security of safety harnesses, ropes or handrails. Even looking at these photos unnerves many people, because we humans generally have an instinctive fear of being pulled to our deaths by the force of gravity. How do these forces work?

What is gravity? Each particle of matter attracts every other particle, the force is proportional to the mass of, and the distance between the objects. Massive bodies such as planets exert very powerful forces .The Earth is surrounded by a gravitational field which exerts a force of attraction on other objects.

When an object on Earth is situated on a hard surface, there is an upward contact force that balances the downward gravitational force; the force on the mass of the object is its weight.

When there is no contact force to oppose the gravitational force the object falls freely and is pulled towards the surface of the Earth. The gravitational pull causes an object to accelerate at a constant rate of 9.8metres per second, for each second of the descent.

Even when an object is falling freely downwards, there are upward restraining forces such as air resistance and these are called drag forces. As an object continues to increase its velocity downwards, the drag also increases, at a certain point the drag force and gravitational force become equal and the object stops accelerating and moves at a constant velocity called terminal velocity. 

When the falling object collides with the surface of the Earth an impact force will be experienced, but the dynamics of the collision can be influenced by a number of factors eg soft surface.

Despite the force of gravity, many  creatures spend their lives in mid air seemingly defying this powerful force.

Birds, bats, reptiles and insects use the force of drag and lift to counter the force of gravity, some species can only glide but others such as birds, insects and bats can both glide and fly.

In gliding, wings push air downward and by Newtons Third Law an opposite force pushes the wings upward, which supports and slows the descent.

In flying, wings act as an aerofoil and are flapped and rotated to create both lift and thrust. To avoid pushing air backwards when they flap their wings, most wing movement is angled so the motion is similar to rowing in the sky.

Insects fly by rotating or whirling their wings in a figure 8 pattern that acts as a propeller. They can move their wings at up to 1000 beats per second – the fastest known muscles.
Many plants rely on the wind to disperse their seeds and may have all manner of adaptations for flying –gliders, parachutes, helicopter and spinners are all types of seeds adaptations.

Share this post

Submit to DeliciousSubmit to DiggSubmit to FacebookSubmit to Google PlusSubmit to StumbleuponSubmit to TechnoratiSubmit to TwitterSubmit to LinkedIn

Injured Wildlife

   Wildcare SEQ



Animal Control

Photo Gallery Tree

Random Images - NHA

  • 2017-05-13 Larapinta Trail
  • Description: Larapinta Trail
  • Ohia Court 25
  • Description: 2014-02-28 Nature Walk at Ohia Court regeneration area
  • 2010-07-10 Federation Walk
  • Description: Bushwalking in SE Qld
  • 2012-07-21 Killarney Glen & Denham Reserve
  • Description: Bushwalking in SE Qld

Why does attentiveness to nature matter? In a very fundamental sense, we are what we pay attention to. Paying heed to beauty, grace, and everyday miracles promotes a sense of possibility and coherence that runs deeper and truer than the often illusory commercial, social "realities" advanced by mainstream contemporary culture. ... Our attention is precious, and what we choose to focus it on has enormous consequences. What we choose to look at, and to listen to--these choices change the world. As Thich Nhat Hanh has pointed out, we become the bad television programs that we watch. A society that expends its energies tracking the latest doings of the celebrity couple is fundamentally distinct from one that watches for the first arriving spring migrant birds, or takes a weekend to check out insects in a mountain stream, or looks inside flowers to admire the marvelous ingenuities involved in pollination. The former tends to drag culture down to its lowest commonalities; the latter can lift us up in a sense of unity with all life. The Way of Natural History, edited by Thomas Lowe Fleischner and published by Trinity University Press (Texas)