In 1827 Robert Brown, a Scottish botanist, was
observing some pollen grains in water through a microscope
. … He also predicted how far the pollen grains would be moved. When his predictions were later shown to be correct, it was conclusive proof for his ideas and the particle theory of matter.
How did Einstein explain what it was Brownian motion?
In a separate paper, he applied the molecular theory of heat to liquids to explain the puzzle of so-called “Brownian motion”. … Einstein then
reasoned that if tiny but visible particles were suspended in a liquid, the invisible atoms in the liquid would bombard the suspended particles and cause them to jiggle
.
What was Robert Brown’s first hypothesis to explain the movement of the pollen grains?
At first Brown thought the
pollen grains were moving because they were alive
. So he looked at some 100 year old pollen grains on water and observed the same type of random motion. These old grains were definitely not alive and he could not explain the movement of the tiny particles that was called Brownian motion.
What did Robert Brown experiment with?
In 1827, the Scottish botanist Robert Brown looked through
a microscope at pollen grains suspended in water
, and discovered what we now call Brownian Motion. It was an unintentional discovery. He was not looking for the effect that now bears his name, but was, rather, curious about reproduction.
What was Robert Brown’s first hypothesis?
At first Brown thought
the pollen grains were moving because they were alive
. So he looked at some 100 year old pollen grains on water and observed the same type of random motion. These old grains were definitely not alive and he could not explain the movement of the tiny particles that was called Brownian motion.
Why are pollen grains important?
Pollen is
essential for sexual reproduction of flowering plants and plants that produce cones
. Each pollen grain contains male gametes necessary for fertilisation. The scientific study of living and fossilised pollen grains is known as palynology.
Who discovered nucleus in cell?
By 1836, the nucleus — discovered by
Brown in 1831
— was a relatively familiar structure, as was the nucleolus, named by Schleiden. The names of Schleiden and Schwann are almost as closely linked to the cell theory
What is Brownian motion in simple words?
Brownian motion, also called Brownian movement,
any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations
. … The physical process in which a substance tends to spread steadily from regions of high concentration to regions of lower concentration is called diffusion.
What was Einstein’s theory of general relativity in simple terms?
General relativity is a
theory of space and time
. The theory was published by Albert Einstein in 1915. The central idea of general relativity is that space and time are two aspects of spacetime. Spacetime is curved when there is matter, energy, and momentum resulting in what we perceive as gravity.
What is Einstein’s general theory of relativity?
Einstein’s 1915 general theory of relativity holds
that what we perceive as the force of gravity arises from the curvature of space and time
. The scientist proposed that objects such as the sun and the Earth change this geometry.
What is the contribution of Robert Brown?
Robert Brown, (born December 21, 1773, Montrose, Angus, Scotland—died June 10, 1858, London, England), Scottish botanist best known for his
descriptions of cell nuclei and of the continuous motion of minute particles in solution
, which came to be called Brownian motion.
Who gave jobs to Robert Brown?
Banks approved
Flinders
‘ proposal, and in December 1800 wrote to Brown offering him the position of naturalist to the expedition.
What Robert Hooke discovered about cells?
While observing cork through his microscope, Hooke saw tiny boxlike cavities, which he illustrated and described as cells. He had discovered
plant cells
! Hooke’s discovery led to the understanding of cells as the smallest units of life—the foundation of cell theory
Is a pollen grain alive?
Is a pollen grain alive?
Yes
. Pollen is a plant dispersal mechanism for sexual reproduction that contains a male gametophyte in a protein capsule.
What does pollen do to humans?
Many people have an
adverse immune response
when they breathe in pollen. The immune system normally defends the body against harmful invaders — such as viruses and bacteria — to ward off illnesses. In people with pollen allergies, the immune system mistakenly identifies the harmless pollen as a dangerous intruder.
How is pollen grain formed?
Pollen grains are produced
by meiosis of microspore mother cells
that are located along the inner edge of the anther sacs (microsporangia). … Inside the pollen are two (or, at most, three) cells that comprise the male gametophyte. The tube cell (also referred to as the tube nucleus) develops into the pollen tube.
