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J. Perelman
"Entertaining physics". Book 1.
Chapter 3. The resistance of the medium


Plants often seek the services of gliders - for distribution of its fruits and seeds. Many of the fruits and seeds are equipped with either a bunch of hairs (Pappus dandelion, salsify, cotton), which act like a parachute, or supporting surfaces in the form of spikes, protrusions, etc. Such plant gliders can be observed in conifers, maples, elms, birch, hornbeam, Linden, many umbrella and so on

In his famous book Kerner von Marilaun “Life of plants” read about this the following:

“When the wind on Sunny days, plenty of fruit and seeds rises vertical airflow to a considerable height, but after sunset usually falls back close to. Such flights are important not so much for the distribution of plants in breadth, but for settlements on ledges and in crevices of steep slopes and cliffs, where the seeds might not get otherwise. Horizontally as current air mass is able to endure soaring in the air, the fruits and seeds at very great distances.

In some plants the wings and parachutes remain in connection with seeds only during the flight. Seeds of nettle quietly floating in the air, but as soon as you meet an obstacle, the seed is separated from the parachute and falls to the ground. This explains the frequent growth of nettle along walls and fences. In other cases, the seed remains connected to the parachute”.

The figures below depict some fruits and seeds have “gliders”.

The fruit of salsify.

Volatile plant seeds; a - lionfish maple, b - pine-tree, c - tree, d - birch.

Vegetable gliders in many ways even more perfect human. They raise comparatively with its own weight much more cargo. In addition, this herbal plane differs automatic stability: if the seed Indian Jasmine to turn, it will turn back convex side down; if in flight the seed meets an obstacle, it never loses balance, falls, and gently lowered down.

Entertaining physics J. Perelman


System Orphus


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