Word Finder - concave

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A concave surface or curve.

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The vault of the sky.

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One of the celestial spheres of the Ptolemaic or geocentric model of the world.

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Aristotle makes [Fire] to move to the concave of the Moon. - Thomas Salusbury (1661).

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An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.

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An indentation running along the base of a surfboard, intended to increase lift.

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An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.

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To render concave, or increase the degree of concavity.

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Curved like the inner surface of a sphere or bowl

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(of a polygon) not convex; having at least one internal angle greater than 180 degrees.

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(of a real-valued function on the reals) satisfying the property that all segments connecting two points on the function's graph lie below the function.

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Hollow; empty

Concave Lenses are used in the treatment of myopia or shortsight.

He refers to Maurolycus' work with concave specula.

Rayleigh points out that this clinging of the sound to the surface of a concave wall does not depend on the exactness of the spherical form.

The facial line is concave.

Screws.The figure of a screw is that of a convex or concave cylinder, with one or more helical projections, called threads, winding round it.

The dried insect has the form of irregular, fluted and concave grains, of which about 70,000 go to a pound.

A marine inlet where the coastline usually follows a concave curve between rocky headlands.

The concave dorsal fin begins above the base of the ventral fins.

Others look best when the blush is applied just under the apples of their cheeks, in the concave of the cheekbone.

The Carnival logo is a simple reverse C character, with a white reverse C framed with blue on the concave (left) side and red on the convex (right) side.

Prior to his invention around 1760, the convex and concave lenses (farsighted and nearsighted lenses respectively) were worn separately.

In fact, convex lenses used to correct farsightedness came along nearly 300 years before the concave lenses to correct nearsightedness did.

Franklin just took the two, almost 200 years after the concave lenses were designed for near vision, and created an eyeglass that housed both types.

The use of concave lenses (lenses that depress inward) to correct nearsightedness is attributed to Nicholas of Cusa and the thought that specific lenses were required to ease various problems with vision prevailed for centuries.

Fingernails may be small and concave with pitting, ridges, splits, and/or discoloration.

These are also called concave, angle, stacked, and wedge bobs.

To make a valley fold, you should fold one section of the paper up and over the other section - creating a concave crease.

The theater is also much different than a standard theater, where the screen is actually slightly concave.

It is common for people with scoliosis to take in less air on the concave side of the spine.

By focusing on the breath and directing it into the concave side of the spine, the muscles stretch and increase lung capacity.

On the concave, or front, side of the paper plate, arrange the handprints in a circle with the fingers pointing out, like rays of sunshine.

On the other hand, to produce convergence with water or hydrogen gas, in both which the velocity of sound exceeds its rate in air, the lens ought to be concave.

From the above account it will at once appear that between the convex and the concave margins of the Alpine chain there is a striking difference.

The ground should be excavated to the depth of a foot or more - the bottom being made firm and slightly concave, so that it may slope to the centre, where a drain should be introduced; or the bottom may be made convex and the water allowed to drain away at the sides.

Usually the under or concave edge of the arc is the more clearly defined, and adjacent to it the sky often seems darker than elsewhere.

If an object has to be beaten into concave form from a flat thin sheet, the outer portions must be hammered until they occupy smaller dimensions than on the flat sheet.

The result is that the object assumes a smooth concave and convex shape, without the thickness of the metal becoming reduced.

Kepler, who examined Porta's account of his concave and convex lenses by desire of his patron the emperor Rudolph, declared that it was perfectly unintelligible.

All the original Dutch telescopes were composed of a convex and a concave lens, and telescopes so constructed do not invert.

James Gregory, in his Optica Promota (1663), discusses the forms of images and objects produced by lenses and mirrors, and shows that when the surfaces of the lenses or mirrors are portions of spheres the images are curves concave towards the objective, but if the curves of the surfaces are conic sections the spherical aberration is corrected.

The triple object-glass, consisting of a combination of two convex lenses of crown glass with a concave flint lens between them, was introduced in 1765 by Peter, son of John Dollond, and many excellent telescopes of this kind were made by him.

The substitution of a positive or negative eye-piece for the simple convex or concave eye-lens, and of an achromatic object-glass for the simple object-lens, transforms these, early forms into the modern achromatic telescope.

A A and B B are concave mirrors having a common axis and their concavities facing each other.

A A is a concave mirror whose axis is a a.

Both mirrors are usually concave; if plane, a concave lens is placed immediately before them.

In the rat-kangaroos, or kangaroo-rats, as they are called in Australia, constituting the sub-family Potoroinae, the first upper incisor is narrow, curved, and much exceeds the others in length; the upper canines are persistent, flattened, blunt and slightly curved, and the first two premolars of both jaws have large, simple, compressed crowns, with a nearly straight or slightly concave free cutting-edge, and both outer and inner surfaces usually marked by a series of parallel, vertical grooves and ridges.

He did not, however, enter into the explanation of particular phenomena, as this had been done already by Laplace, but he pointed out to physicists the advantages of the method of Segner and Gay Lussac, afterwards carried out by Quincke, of measuring the dimensions of large drops of mercury on a horizontal or slightly concave surface, and those of large bubbles of air in transparent liquids resting against the under side of a horizontal plate of a substance wetted by the liquid.

It is also practically independent of the curvature of the surface, although it appears from the mathematical theory that there is a slight increase of tension where the mean curvature of the surface is concave, and a slight diminution where it is convex.

When the surface is curved, the effect of the surface-tension is to make the pressure on the concave side exceed the pressure on the convex side by T (1 /R I i /R 2), where T is the intensity of the surface-tension and R 1, R2 are the radii of curvature of any two sections normal to the surface and to each other.

The mean curvature of these surfaces is, therefore, concave towards the axis.

If the mean curvature is concave towards the axis the film will tend to approach the axis.

So closely allied are these two fishes that their distinctness can be proved only by an examination of the gill-apparatus, the allis shad having from sixty to eighty very fine and long gill-rakers along the concave edge of the first branchial arch, whilst the twaite shad possesses from twenty-one to twenty-seven stout and stiff gill-rakers only.

That which flows from the lower incisions is often collected on tiles or on a concave piece of the prickly pear (Opuntia), but is less crystalline and more glutinous, and is less esteemed.

The muscular system of the Scyphomedusae is developed on the subumbral surface as a system of circularly disposed fibres which by their contraction make the umbrella more concave and diminish its FIG.

It is, as a rule, deeply concave on its FIG.

It only remains to be stated that the wing acts as a true kite, during both the down and the up strokes, its under concave or biting surface, in virtue of the forward travel communicated to it by the body of the flying creature, being closely applied to the air, during both its ascent and its descent.

As the down and up strokes run into each other, and the convex surface of the wing is always directed upwards and the concave surface downwards, it follows that the upper surface of the wing evades in a great measure the upper air, while the under surface seizes the nether air.

During the up stroke of the piston the wing is very decidedly convex on its upper surface (a b c d, A A'); its under surface (e f g h, A A') being deeply concave and inclined obliquely upwards and forwards.

This is due to a stratum of hot air at some distance above the sea level, the rays of light near the horizon being practically horizontal, while those at greater elevations are fairly concave.

There are two non-singular kinds, the one with, the other without, an oval, but each of them has an infinite (as Newton describes it) campaniform branch; this cuts the axis at right angles, being at first concave, but ultimately convex, towards the axis, the two legs continually tending to become at right angles to the axis.