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Allometric growth
A pattern of growth in which the length of one feature grows at a rate proportional to a power of the length of another feature.
Area-volume tension
A result of the fact that, as an object is scaled up, the volume increases faster than the surface area and faster than areas of cross sections.
Crushing strength
The maximum ability of a substance to withstand pressure without crushing or deforming.
Density
Weight per unit volume.
Geometrically similar
Two objects are geometrically similar if they have the same shape, regardless of the materials of which they are made; They need not be of the same size; Corresponding linear dimensions must have the same factor of proportionality.
Isometric growth
Proportional growth.
Linear scaling factor
The number by which each linear dimension of an object is multiplied when it is scaled up or down; that is, the ratio of the length of any part of one of two geometrically similar objects to the length of the corresponding part of the second.
Logarithmic scale
A scale on which equal divisions correspond to powers of 10.
Log-log paper
Graph paper on which both the vertical and the horizontal scales are logarithmic scales, that is, the scales are marked in orders of magnitude 1, 10, 100, 1000, . . . , instead of 1, 2, 3, 4, . . . .
Mass
The aspect of matter that is affected by forces, according to physical laws.
Orders of magnitude
Powers of 10.
Power curve
A curve described by an equation y = bx to the a, so that y is proportional to a power of x.
Pressure
Weight divided by area.
Problem of scale
As an object or being is scaled up, its surface and cross-sectional areas increase at a different rate from its volume, forcing adaptations of materials or shape.
Proportional growth
Growth according to geometric similarity: the length of every part of the organism enlarges by the same linear scaling factor.
Semilog paper
Graph paper on which only one of the scales is a logarithmic scale.
Wing loading
Weight supported, divided by wing area.