· Einstein’s theory for Brownian motion: The motion of tiny particles suspended in liquid is caused by the kinetic energy of the liquid’s molecules.
In 1827 the Scottish botanist Robert Brown (1773–1858), while using a microscope, observed that pollen grains suspended in water were in constant motion, which he supposed was caused by some ‘‘life’’ in the pollen. He added minute particles of nonliving matter to water and observed the same motion. This phenomenon was not explained until the kinetic theory of molecular motion was revealed. Albert Einstein derived the first theoretical formula to explain why these small particles moved in a liquid when the particles themselves were not molecules. His equation was based on the concept that the average displacement of the particles is caused by the motion resulting from the kinetic energy of the molecules in the liquid. This resulted in a better understanding of the atomic and molecular activity of matter, and thus heat.
Einstein’s theory of the nature of light:
Electromagnetic radiation propagated through
space (vacuum) will act as particles (photons) as well as waves since such radiation is affected
by electric and magnetic fields, and gravity.
space (vacuum) will act as particles (photons) as well as waves since such radiation is affected
by electric and magnetic fields, and gravity.
James Clerk Maxwell developed an equation stipulating that electromagnetic radiation can travel only as waves. This concept troubled Einstein, as did the experiments by Philipp Lenard who had observed the photoelectric effect of ultraviolet light ‘‘kicking’’ electrons off the surface of some metals. It was determined that the number of electrons emitted from the metal was dependent on the strength (intensity) of the radiation. In addition, the energy of the electrons ejected was dependent on the frequency of the radiation. This did not jibe with classical physics.
This predicament was solved by Einstein’s famous suggestion that electromagnetic radiation (light) flows not just in waves but also as discrete particles he called photons. Max Planck referred to these as quanta (very small bits) .
Using Planck’s equation, E = h¯ * v, where E stands for the energy of the radiation, h¯ is Plank’s constant, and v is the frequency, Einstein was able to account for the behavior of light as massless particles with momentum (photons) that have some characteristics of mass, for example, momentum (mass * velocity), as well as characteristics of waves. It resulted in Einstein being awarded the 1921 Nobel Prize for Physics.
Einstein’s concept of mass:
The at-rest mass of an object will increase as its velocity
approaches the speed of light.
When a body with mass is not moving, it is at rest as far as the concept of inertia is concerned, meaning it is resistant to movement by a force. An analogy would be slowness, motionlessness, or languidness in a human being. Once an at-rest mass is in motion (i.e., velocity), it attains momentum (mass * velocity). When there is an increase in its velocity, there is also an increase in the body’s mass. Thus, if a mass attained the speed of light, it would not only require all the energy in the universe to accomplish this, but also would equal all the mass in the entire universe ! . Therefore, it is impossible for anything with mass (except electromagnetic radiation, i.e., light) to attain the speed of light. This is one reason that light must be considered as being both a wave and a particle.
Newton’s three laws that relate to mass and motion represent a classical, mechanistic concept of the universe. Newton’s laws are deterministic based on the conservation of mass that states that matter cannot be created or destroyed. Although weight is proportional to mass, the weight of an object varies as to its position in reference to Earth (or other body with mass in the universe) and thus gravitational attraction, whereas the mass of an object is independent of gravity. The mass of an object (matter) is the same regardless of its location in the universe and thus is independent of gravity. At the same time, we might say that in deep outer space, mass has near zero weight.
Einstein’s theories of relativity eventually changed the Newtonian concepts of mass and motion. In modern physics, the mass of an object changes as its velocity changes, particularly as the velocity approaches the speed of light. This phenomenon is not obvious on Earth because our everyday velocities are far less than that of light. For instance, the at-rest mass of an object will double when it attains a velocity of 160,000 miles per second. This is approaching the speed of light, which is 186,000 miles per second, and even a very small mass is incapable of attaining the speed of light.. When masses with extremely high velocities interact, nuclear reactions can occur , where mass can be converted into energy—thus the famous Einstein equation, E = mc2
, where E is the energy, m is the mass of the object, and c2 is the constant for the velocity of light squared .