Answer 1:
This is a tricky question. Matter is defined by some scientists as anything that has mass and takes up space.
Other scientists have defined matter as the substance that constitutes all
physical objects and of which the observable
Universe is composed. This definition does not
distinguish between mass and energy because,
according to Einsteins theory of relativity
E = M C2, mass can be converted into energy during chemical and nuclear reactions.
This transformation of mass to energy suggests
that matter and energy, such as light, are
fundamentally related.
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If we accept the first definition of matter, then light and sound are themselves not forms of matter. However, both light and sound either originate from matter or occur as a result of the interactions and movements of matter.
Matter is predominantly composed of atoms. Light neither has mass nor takes up space, and is composed of photons rather than atoms. Photons are wavelike particles of energy that originate from chemical or nuclear reactions that occur within and between the atoms of matter. Light, also called electromagnetism, electromagnetic energy or
electromagnetic radiation, is one of the four
fundamental forces or interactions of nature click
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These four fundamental interactions also include gravity (the pull that everybody of mass exerts on every other body of mass), and the two types of nuclear forces that hold atoms together and describe the interactions between neutrons,protons, and electrons inside every atom. Light (photons) is emitted from matter as a form of energy release during chemical reactions (such as fires or combustion) and nuclear reactions (such as occurs
inside the sun and other stars or during the
detonation of atomic bombs). This type of energy
release often occurs when chemical bonds (bonds
between atoms) are broken or formed or when
nuclear bonds (bonds within atoms) are broken or
formed. When this energy is released as light,
the matter that is reacting loses some of its
mass, as Einstein predicted, demonstrating the
conversion of matter to energy.
Sound is very different from light. Instead of being energy that is released from matter, sound is caused by the movement or vibration of matter, often in the form of compression (or pressure) waves. The technical definition for sound is an
alternation in pressure, particle displacement, or particle velocity propagated in an elastic material. This simply means that sound consists of the changing motion of atoms and molecules through matter.
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Whenever you make a sound, whether in the air, water, or through a solid object, you are usually causing that form of matter to alternately compress and expand. The compressions and expansions of that matter cause pressure changes in the air(or water) around our head, which are then detected by our ears as pressure changes felt upon our eardrum. This is what we hear as sound or noise: pressure changes in the fluid (matter) around our ears, caused by vibrations or movements of the particles in this matter. |