Both are made of the same material, not talking about the tempered glass. But I don't see marbles shatter the way glass panel does, why is that? If I could scale up the marble to the size of a car and strike a hammer on it, would it shatter?
collision – Why Marbles Don’t Shatter Like Glass: A Material Science Perspective
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The short answer is: Because metals are really absorptive (which comes from the fact that the nearly free electrons in the metal follow the oscillations of the radiation thereby depleting its energy), but some only in part of the visible range.
The reflectivity of a material is given by the Fresnel equations in terms of the index of refraction. They describe the angle dependency and further tell you that the higher the difference in the index of refraction the more light will be reflected at the interface.
It is important to understand, that the index of refraction in general can be a complex number. The imaginary part of the index of refraction describes the absorption of the material, while the (well known) real part describes the usual "optical density" causing refraction. So there are two possibilities for a material to reflect strongly: Either because it has a large real part of the index of refraction (like diamond) or because it absorbs light strongly (like metals). The latter effect can also be seen with lines written using a dark overhead transparency marker: they reflect in the colour range that does not pass through.
So, the reflection on the surface of metals is mainly due to the imaginary part of the index of refraction (that is, the absorptivity). For coloured metals like copper or gold the so called "plasma frequency" of the metal above which the metal begins to loose its strong absorptivity is in the visible range (or in the near UV). Therefore such metals only reflect a portion of the spectrum, well you get a tinted reflection.
The other materials (plastic, glass, apples) have one thing in common: they have a relatively low absorptivity (while for metals the wave only enters a few nanometers, the other materials range from transparent to waves entering at least several micrometers; the absorption caused by pigments in the material is typically much weaker than the one in metals). This means that the reflection is caused by the change of the real part of the index of refraction. As most materials are only slightly dispersive in the optical range, this means that all frequencies are reflected more or less equally, therefore the reflection is not tinted.
I'm surprised this question has remained unanswered for so long. And yes, I agree that the web page provided gives a completely unsatisfactory answer. The solution to the problem is fairly complex, so we need to break it down into a number of issues to look at.
The cracks radiating from the center of impact are easy to explain. Flat glass laid on the ground and hit with a hammer also produces these radial cracks from the centre of impact. This is caused by the rigidly flat surface trying to form a cone shape. You can only cut triangles (around a point) in a flat surface, and allow those triangles to spread apart at the apex to form a cone.
Flat glass laid on the ground tends to have few lateral or circular cracks, depending on irregularities of the ground. If you hold a piece of flat glass horizontally and hit it with a hammer then the cracks and broken pieces tend to be more random, but since you are holding a point you often get radial cracks emanating from that point. It is much safer to hold flat glass vertically when hitting it with a hammer as the radiating cracks emanate from the impact point.
The speed of sound within a material and its elasticity definitely has an effect on the formation of the lateral or circular cracks. In so far as the distance between them from the centre of impact, is produced by a "deformation wave" spreading out.
Formation of lateral cracks are caused by a lever like action that is easiliest explained by taking a ruler and holding it down so that it overhangs a desk. Push down on the unsupported end with your other hand, and you will find that the (freely moving) length of the overhang acts like a lever to break the ruler near the rigidly held end.
When an object stops it does not just stop instantly, it has to "decelerate" in the same way that an object has to accelerate to get up to speed. Even a rubber ball thrown against a brick wall spends a small amount of time deforming and storing its kinetic energy of motion in its elastic bonds, which in turn is release as the ball "springs" back away from the wall.
Laminated windscreens are a thin piece of soft plastic "sandwiched" between two thin pieces of glass. The idea is that shattering glass that is stuck to the plastic does not go flying about. Normal safety glass relies on the pieces being very small, so that they do not have a lot of energy to do damage to the occupants.
The soft plastic also absorbs some of the energy of the colliding object. The elastic bonds within it stretch and break, this takes energy to do which is subtracted from the kinetic energy of the object. The plastic also "holds onto" the surrounding glass so energy is transmited and taken up over a greater area.
As an object hits this type of windscreen the "spiderweb" is formed in the following manner. At first the object has a lot of velocity (and so kinetic energy), enough that the "deformation wave" does not have enough time to spread out far before the length of the "levers" combined with force of the decelerating object are enough to reach the "snap now" point.
Later in the deceleration of the object (when it is going slower) the "deformation wave" has longer to spread out, and levers have to be longer (with a reduced force) to reach that "snap now" point. Hence the distance between concentric rings of cracks are smaller near the point of impact, and farther apart at greater distance.
Best Answer
The difference is geometry, both in shape and size.
First, consider that the smaller something is, the stiffer it is in general. Take a large rubber eraser and squeeze it (in compression, not bending) and then cut it in half and squeeze again. You need double the force to get the same deflection with half the size.
Next is the shape, where something flat like a glass pane is allowed to bend which puts the most strain into the material, compared to a sphere that mostly compresses. The details here are complex, but certain shapes are stiffer and certain ones are more complaint. A sphere is exceptional at resisting loading because most of the internal stresses are compressive.
Brittle shattering occurs when the bonds between molecules in a solid break (in tension) causing a dislocation, which then loads up neighboring molecules which in turn break also. In the end, there is a runaway process of crack propagation until the object is fully cracked.