Which Microscope Did Robert Hooke Use To Study Tree Bark?

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Which Microscope Did Robert Hooke Use To Study Tree Bark
Compound microscope Answer and Explanation: To study the composition of tree bark, Robert Hooke used a compound microscope that he designed and created.
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Which microscope is used by Robert Hooke?

Robert Hooke No portrait survives of Robert Hooke. His name is somewhat obscure today, due in part to the enmity of his famous, influential, and extremely vindictive colleague, Sir Isaac Newton. Yet Hooke was perhaps the single greatest experimental scientist of the seventeenth century.

His interests knew no bounds, ranging from physics and astronomy, to chemistry, biology, and geology, to architecture and naval technology; he collaborated or corresponded with scientists as diverse as Christian Huygens,, Christopher Wren, Robert Boyle, and Isaac Newton. Among other accomplishments, he invented the universal joint, the iris diaphragm, and an early prototype of the respirator; invented the anchor escapement and the balance spring, which made more accurate clocks possible; served as Chief Surveyor and helped rebuild London after the Great Fire of 1666; worked out the correct theory of combustion; devised an equation describing elasticity that is still used today (“Hooke’s Law”); assisted Robert Boyle in studying the physics of gases; invented or improved meteorological instruments such as the barometer, anemometer, and hygrometer; and so on.

He was the type of scientist that was then called a virtuoso – able to contribute findings of major importance in any field of science. It is not surprising that he made important contributions to biology and to paleontology. Relatively little is known about Robert Hooke’s life.

He was born on July 18, 1635, at Freshwater, on the Isle of Wight, the son of a churchman. He was apparently largely educated at home by his father, although he also served an apprenticeship to an artist. He was able to enter Westminster School at the age of thirteen, and from there went to Oxford, where some of the best scientists in England were working at the time.

Hooke impressed them with his skills at designing experiments and building equipment, and soon became an assistant to the chemist Robert Boyle. In 1662 Hooke was named Curator of Experiments of the newly formed Royal Society of London – meaning that he was responsible for demonstrating new experiments at the Society’s weekly meetings.

He later became Gresham Professor of Geometry at Gresham College, London, where he had a set of rooms and where he lived for the rest of his life. His health deteriorated over the last decade of his life, although one of his biographers wrote that “He was of an active, restless, indefatigable Genius even almost to the last.” He died in London on March 3, 1703.

Hooke’s reputation in the history of biology largely rests on his book Micrographia, published in 1665. Hooke devised the compound microscope and illumination system shown above, one of the best such microscopes of his time, and used it in his demonstrations at the Royal Society’s meetings.

  1. With it he observed organisms as diverse as,,,, and feathers.
  2. Micrographia was an accurate and detailed record of his observations, illustrated with magnificent drawings, such as the flea shown below, which Hooke described as “adorn’d with a curiously polish’d suite of sable Armour, neatly jointed.

,” It was a best-seller of its day. Some readers ridiculed Hooke for paying attention to such trifling pursuits: a satirist of the time poked fun at him as “a Sot, that has spent 2000 £ in Microscopes, to find out the nature of Eels in Vinegar, Mites in Cheese, and the Blue of Plums which he has subtly found out to be living creatures.” More complimentary was the reaction of the diarist and government official Samuel Pepys, who stayed up till 2:00 AM one night reading Micrographia, which he called “the most ingenious book that I ever read in my life.” Which Microscope Did Robert Hooke Use To Study Tree Bark

P erhaps his most famous microscopical observation was his study of thin slices of cork, depicted above right. In “Observation XVIII” of the Micrographia, he wrote:

, I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular. these pores, or cells,, were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this.

  1. Hooke had discovered plant cells – more precisely, what Hooke saw were the cell walls in cork tissue.
  2. In fact, it was Hooke who coined the term “cells”: the boxlike cells of cork reminded him of the cells of a monastery.
  3. Hooke also reported seeing similar structures in wood and in other plants.
  4. In 1678, after had written to the Royal Society with a report of discovering “little animals” – bacteria and protozoa – Hooke was asked by the Society to confirm Leeuwenhoek’s findings.

He successfully did so, thus paving the way for the wide acceptance of Leeuwenhoek’s discoveries. Hooke noted that Leeuwenhoek’s simple microscopes gave clearer images than his compound microscope, but found simple microscopes difficult to use: he called them “offensive to my eye” and complained that they “much strained and weakened the sight.” Hooke was also a keen observer of fossils and geology.

While some fossils closely resemble living animals or plants, others do not – because of their mode of preservation, because they are extinct, or because they represent living taxa which are undiscovered or poorly known. In the seventeenth century, a number of hypotheses had been proposed for the origin of fossils.

One widely accepted theory, going back to Aristotle, stated that fossils were formed and grew within the Earth. A shaping force, or “extraordinary Plastick virtue,” could thus create to stones that looked like living beings but were not. Hooke’s contemporary, the naturalist and shell collector Martin Lister wrote in 1678 that “our English Quarry-shells were not cast in any Animal mold, whose species or race is yet to be found in being at this day.” We would now interpret these fossils as belonging to extinct taxa, but extinction was not widely accepted at the time, and Lister concluded: “I am apt to think, there is no such matter, as Petrifying of Shells in the business.

but that these Cockle-like shells ever were, as they are at present, lapides sui generis, and never any part of an Animal.” Hooke examined fossils with a microscope – the first person to do so – and noted close similarities between the structures of petrified wood and fossil shells on the one hand, and living wood and living mollusc shells on the other.

In Micrographia he compared a piece of petrified wood with a piece of rotten oak wood, and concluded that this petrify’d Wood having lain in some place where it was well soak’d with petrifying water (that is, such water as is well impregnated with stony and earthy particles) did by degrees separate abundance of stony particles from the permeating water, which stony particles, being by means of the fluid vehicle convey’d, not onely into the Microscopical pores.

  • But also into the pores or Interstitia.
  • Of that part of the Wood, which through the Microscope, appears most solid.
  • Hooke’s language may be archaic, but his meaning is quite modern: Dead wood could be turned to stone by the action of water rich in dissolved minerals, which would deposit minerals throughout the wood.

Hooke also concluded in Micrographia that the shell-like fossils that he examined really were “the Shells of certain Shel-fishes, which, either by some Deluge, Inundation, earthquake, or some such other means, came to be thrown to that place, and there to be fill’d with some kind of Mud or Clay, or petrifying Water, or some other substance. Hooke’s Discourse of Earthquakes, published two years after his death, shows that his geological reasoning had gone even further. Following in the footsteps of, Hooke explained the presence of fossil shells on mountains and in inland regions: “Most of those Inland Places.

Are, or have been heretofore under the Water. the Waters have been forc’d away from the Parts formerly cover’d, and many of those surfaces are now raised above the level of the Water’s Surface many scores of Fathoms. It seems not improbable, that the tops of the highest and most considerable Mountains in the World have been under Water, and that they themselves most probably seem to have been the Effects of some very great Earthquake.” Hooke continued to study fossils and compare them with living organisms – the illustration above shows the coiled shells of three living cephalopods, Nautilus, Argonauta, and Spirula, compared with a fossil ammonite (upper right).

He concluded that many fossils represented organisms that no longer existed on Earth: “There have been many other Species of Creatures in former Ages, of which we can find none at present; and that ’tis not unlikely also but that there may be divers new kinds now, which have not been from the beginning.” Hooke had grasped the cardinal principle of paleontology – that fossils are not “sports of Nature,” but remains of once-living organisms that can be used to help us understand the history of life.

Hooke realized, two and a half centuries before Darwin, that the fossil record documents changes among the organisms on the planet, and that species have both appeared and gone extinct throughout the history of life on Earth. These questions of the nature of fossils and the possibility of extinction would continue to challenge natural scientists, from Edward Lhwyd and down to and,

is an excellent, well-illustrated site on Hooke’s life and work, including a number of images from Micrographia, : Robert Hooke
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What did Robert Hooke discover with a microscope?

In 1665, Robert Hooke published Micrographia, a book filled with drawings and descriptions of the organisms he viewed under the recently invented microscope, The invention of the microscope led to the discovery of the cell by Hooke. While looking at cork, Hooke observed box-shaped structures, which he called “cells” as they reminded him of the cells, or rooms, in monasteries.

  • This discovery led to the development of the classical cell theory,
  • The classical cell theory was proposed by Theodor Schwann in 1839.
  • There are three parts to this theory.
  • The first part states that all organisms are made of cells.
  • The second part states that cells are the basic units of life.
  • These parts were based on a conclusion made by Schwann and Matthias Schleiden in 1838, after comparing their observations of plant and animal cells.

The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells), Since the formation of classical cell theory, technology has improved, allowing for more detailed observations that have led to new discoveries about cells.
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Who examined cork bark through a microscope?

Introduction – Robert Hooke, inventor of the first microscope, published a collection of his hand-drawn observations of biological samples in 1665 in a book entitled Micrographia 1 (Fig.1 ). Among the studies of different plants or animals by Hooke, one of the most famous remains the first observation of cork cells from Quercus suber (Fig.2e ).

Optical microscopy allowed this first representation of the basic biological unit by Hooke, which was then defined as a “cell” 2, Cork was described as an alveolar material composed of dead and empty closed cells. It corresponds to the bulk of cork tissue including lenticels, which are open macroporous channels.

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Cork tissue is referred to as the phellem in the present work. A finer description was only reported in 1981 by Gibson et al,3 using scanning electron microscopy (SEM). While Hooke only reported the orientation of cork cells in two directions, Gibson highlighted their specific 3D structure, which is at the origin of the anisotropy of the material.

  • In fact, the structure of phellem cells varies according to the observation plane (Fig.2f ).
  • In the plane perpendicular to the radial direction, cells appear as hexagons that are arranged according to a honeycomb structure.
  • In the two other planes, either perpendicular to the tangential or to the axial directions, they exhibit a rectangular shape and are stacked up, similar to a brick wall.

Furthermore, in the plane perpendicular to the tangential direction, the cell walls are corrugated. Gibson was also the first to point out the relationship between the cork cell structure and the mechanical properties of the material 3, 4, Its remarkable near-zero Poisson’s ratio along the axial direction still makes cork an unique reference for the design of new advanced materials 5, Which Microscope Did Robert Hooke Use To Study Tree Bark Overview of 400 years of cork imaging. Figure 2 Which Microscope Did Robert Hooke Use To Study Tree Bark ( a ) Quercus suber L, tree after cork bark harvesting. ( b ) Representation of the transverse section of cork tree. ( c ) Zoom on the phellogen region with cellular differentiation. ( d ) Tubbing of cork stopper from the cork bark. Letters A, R and T refers to as the axial, radial and tangential directions, respectively.

( e ) First observation of cork cells by Robert Hooke in 1665 1, ( f ) Characteristic shape and dimensions of a phellem cell. The typical anisotropic structure of phellem cells is attributed to the biological development of Quercus suber L. tree. Phellem results from the cell differentiation of the phellogen, which is restricted to one cell layer (Fig.2b ).

After the division from the phellogen cell, a limited thickening of the primary cell wall, which is rich in lignin, occurs. Phellem cells are then subjected to a very rapid suberization as the consequence of an important metabolic activity with an increase in smooth endoplasmic reticulum and the production of vesicles by dictyosomes 8,

  • The genes that are responsible for this metabolic activity have been identified and are known to lead to the synthesis and linkages of the aromatic and aliphatic precursors of suberin 9,
  • Thus, the thick secondary phellem cell wall is a result of this fast suberization.
  • During this phenomenon, the protoplasmic layer also tends to be detached from the cell wall.

Suberin deposition is immediately followed by the formation of the tertiary wall, which is mainly composed of polysaccharides and extractable compounds. Therefore, the development of phellem cells gives rise to a cell wall that is divided into three layers, which are mainly composed of suberin (45 wt %), lignin (22 wt %), polysaccharides (18 wt %) and extractable compounds, such as lipids 10, terpenoids and phenolic compounds (15 wt %) 11, 12,

Crossing the cell walls, thin channels with a diameter of ∼ 50 nm, called plasmodesmata, were recently identified using transmission electron microscopy (TEM) 13, Plasmodesmata act as intercellular channels that mediate the cell-to-cell transport of signaling molecules, such as non-cell autonomous proteins or RNAs, in the living cells 14,

After their development, cork cells are autolyzed and undergo programmed cell death in response to environmental cues 15, 16, Thus, the resulting layer of phellem, which is composed of dead cells, is an efficient insulator, either acting as a barrier to dehydration or as protection against fire for the oak tree in the Mediterranean peninsula.

Nevertheless, to ensure the gaseous exchanges between the oak tree and the environment, the phellem is sprinkled with lenticular phellogen (higher meristematic activity), which leads to the formation of lenticels 17, 18 (Fig.2c ). Lenticels are channels with a diameter in the millimeter scale that represent an open macroporosity across the cork bark.

In the cork industry, cork stoppers are punched out from the tree bark perpendicularly to lenticels (Fig.2a,b,d ). The quality and price of natural cork stoppers are defined according to the external apparent surface porosity constituted by these lenticels, which is often visually determined by qualified workers.

  • However, imaging coupled with image analysis is being used more frequently in this setting to classify cork quality.
  • In that case, the sorting of cork is based on the surface density of lenticels, as determined by the 2D analysis of photographs 19, 20,
  • This sorting is sometimes also performed by probing the inner structure of the cork using X-ray radiography 19,

A higher number of lenticels indicates a lower quality of the cork. Several other imaging techniques have been applied to study cork, such as terahertz millimeter wave 21, near-infrared spectroscopies 22 and more recently confocal microscopy 16 (Fig.1 ) X-ray 23, 24 and neutron tomographies 19 were also used, showing that lenticels are not interconnected within a cork stopper.

  1. This implies that the limiting step in gas transfer is the crossing of cell walls.
  2. However, the mechanism of diffusion through the cork cell wall has not been fully identified 25, as it can occur via surface diffusion through the polymers composing the cell wall 26, 27 and/or via Knudsen diffusion through the plasmodesmata 28, 29,

The use of more recent and powerful imaging techniques can be an effective mean to investigate further the cell wall structure of cork. From the invention of the first microscope to the present day, imaging has been used to describe the structure of cork, the arrangement of its cells and their characteristic dimensions and the spatial distribution of lenticels.

  1. However, the information available in the literature concerning the differences between the phellem cells and the lenticel cells in terms of structure and composition is scarce.
  2. The objective of this paper was to investigate this aspect based on multiscale imaging.
  3. First, at the mesoscale, X-ray computed tomography was applied to characterize the structure and porosity of solid cork stoppers.

Second, structural differences between the cells composing the phellem and those bordering the lenticels were highlighted based on the use of two-photon microscopy. Finally, at the nanoscale, TEM was performed to observe the structure of the plasmodesmata that cross the cell walls.
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Which cells were observed by Robert Hooke for the first time in the bark of?

Robert Hooke observed cork cells for the first time. They looked like box-type structures under the microscope. Cork is obtained from bark of a tree. Cork cells are dead cells.
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Did Robert Hooke use his own microscope?

The Hooke Microscope – Although Hooke did not make his own microscopes, he was heavily involved with the overall design and optical characteristics. The microscopes were actually made by London instrument maker Christopher Cock, who enjoyed a great deal of success due to the popularity of this microscope design and Hooke’s book.

  1. The Hooke microscope shared several common features with telescopes of the period: en eyecup to maintain the correct distance between the eye and eyepiece, separate draw tubes for focusing, and a ball and socket joint for inclining the body.
  2. The microscope body tube was constructed of wood and/or pasteboard and covered with fine leather.

When the draw tubes were fully closed the microscope measured 6 inches long. Although the craftsmanship and design of this microscope was excellent, it suffered from a poorly executed focusing mechanism that would tend to wear very quickly and unevenly.
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What magnification did Robert Hooke use?

Some of Leeuwenhoek’s simple microscopes could magnify objects more than 250 times, but Hooke’s compound microscopes only magnified somewhere between 20 and 50 times.
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What is Robert Hooke most famous for?

English physicist Robert Hooke is known for his discovery of the law of elasticity (Hooke’s law), for his first use of the word cell in the sense of a basic unit of organisms (describing the microscopic cavities in cork), and for his studies of microscopic fossils, which made him an early proponent of a theory of
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Who made the first microscope?

The development of the microscope allowed scientists to make new insights into the body and disease. It’s not clear who invented the first microscope, but the Dutch spectacle maker Zacharias Janssen (b.1585) is credited with making one of the earliest compound microscopes (ones that used two lenses) around 1600.

The earliest microscopes could magnify an object up to 20 or 30 times its normal size. Oil painting by Ernest Board of Leeuwenhoek with his microscope. In the 1660s, another Dutchman, Antonie van Leeuwenhoek (1632-1723) made microscopes by grinding his own lenses. His simple microscopes were more like magnifying glasses, with only one lens.

But the high-quality, hand-ground lenses could magnify an object by up to 200 times. Leeuwenhoek observed animal and plant tissue, human sperm and blood cells, minerals, fossils, and many other things that had never been seen before on a microscopic scale.

  • He presented his findings to the Royal Society in London, where Robert Hooke was also making remarkable discoveries with a microscope.
  • Hooke published the ‘Micrographia’ (1665), an astonishing collection of copper-plate illustrations of objects he had observed with his own compound microscope.
  • While looking at thin slices of cork, Hooke described what he saw as pores: all perforated and porous, much like a Honey-comb,,

these pores, or cells,, were indeed the first microscopical pores I ever saw. He was the first person to use the term ‘cell’ to describe what would later be recognised as the building blocks of all living organisms, plant and animal. Compound microscope designed by Robert Hooke, 1671–1700, and thought to have been made by Christopher Cock of Covent Garden, London.
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What did Hooke call his microscope specimen?

Robert Hooke was a Renaissance Man – a jack of all trades, and a master of many. He wrote one of the most significant scientific books ever written, Micrographia, and made contributions to human knowledge spanning Architecture, Astronomy, Biology, Chemistry, Physics, Surveying & Map Making, and the design and construction of scientific instruments. Robert Hooke placed a sample of blue mold under his microscope and discovered that the mold was actually what he called ‘Microscopical Mushrooms.’
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Who under a microscope observed box like compartments of cork tree bark?

Hooke published, under the title Micrographia, the results of his microscopic observations on several plant tissues. He is remembered as the coiner of the word ‘cell,’ referring to the cavities he observed in thin slices of cork; his observation that living cells contain sap and other materials too often has
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Why did Robert Hooke use a cork?

Robert Hooke’s Cork Surprise Seeing cells through a microscope for the first time, in this Moment of Science. The 17th-century English physicist Robert Hooke was curious about the remarkable properties of cork – its ability to float, its springy quality, its usefulness in sealing bottles.

Hooke investigated the structure of cork with a new scientific instrument he was very enthusiastic about: the microscope. Hooke cut a thin slice of cork with a penknife, put it under his microscope, focused sunlight on it with a thick lens, and looked through the eyepiece. What Hooke saw looked like a piece of honeycomb.

The cork was full of small empty compartments separated by thin walls. He called the compartments “pores, or cells.” He estimated that every cubic inch of cork had about twelve hundred million of these cells. Robert Hooke had discovered the small-scale structure of cork.

And he concluded that the small-scale structure of cork explained its large-scale properties. Cork floats, Hooke reasoned, because air is sealed in the cells. That air springs back after being compressed, and that’s why cork is springy. And that springiness, combined with the fact that the cells are sealed off from each other, explains why a piece of cork is so well suited for sealing a bottle.

Hooke’s observation not only explained the properties of cork, but gave a hint that all living tissue might be made of small building blocks. Our understanding of what those building blocks are has changed since Hooke’s time. Today we’d say that what Hooke observed were dead walls that had been created by living cells when the cork was still part of the tree.
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Who saw the 1st cell while looking at a cork tree using a microscope gave cells their name?

Although they are externally very different, internally, an elephant, a sunflower, and an amoeba are all made of the same building blocks. From the single cells that make up the most basic organisms to the trillions of cells that constitute the complex structure of the human body, each and every living being on Earth is comprised of cells.

  • This idea, part of the cell theory, is one of the central tenants of biology,
  • Cell theory also states that cells are the basic functional unit of living organisms and that all cells come from other cells.
  • Although this knowledge is foundational today, scientists did not always know about cells.
  • The discovery of the cell would not have been possible if not for advancements to the microscope,
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Interested in learning more about the microscopic world, scientist Robert Hooke improved the design of the existing compound microscope in 1665. His microscope used three lenses and a stage light, which illuminated and enlarged the specimens. These advancements allowed Hooke to see something wondrous when he placed a piece of cork under the microscope.

  1. Hooke detailed his observations of this tiny and previously unseen world in his book, Micrographia,
  2. To him, the cork looked as if it was made of tiny pores, which he came to call “cells” because they reminded him of the cells in a monastery.
  3. In observing the cork’s cells, Hooke noted in Micrographia that, “I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular these pores, or cells,were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this” Not long after Hooke’s discovery, Dutch scientist Antonie van Leeuwenhoek detected other hidden, minuscule organisms— bacteria and protozoa,

It was unsurprising that van Leeuwenhoek would make such a discovery. He was a master microscope maker and perfected the design of the simple microscope (which only had a single lens), enabling it to magnify an object by around two hundred to three hundred times its original size.

What van Leeuwenhoek saw with these microscopes was bacteria and protozoa, but he called these tiny creatures “animalcules.” Van Leeuwenhoek became fascinated. He went on to be the first to observe and describe spermatozoa in 1677. He even took a look at the plaque between his teeth under the microscope.

In a letter to the Royal Society, he wrote, “I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving.” In the nineteenth century, biologists began taking a closer look at both animal and plant tissues, perfecting cell theory.

Scientists could readily tell that plants were completely made up of cells due to their cell wall. However, this was not so obvious for animal cells, which lack a cell wall. Many scientists believed that animals were made of “globules.” German scientists Theodore Schwann and Mattias Schleiden studied cells of animals and plants respectively.

These scientists identified key differences between the two cell types and put forth the idea that cells were the fundamental units of both plants and animals. However, Schwann and Schleiden misunderstood how cells grow. Schleiden believed that cells were “seeded” by the nucleus and grew from there.

Similarly, Schwann claimed that animal cells “crystalized” from the material between other cells. Eventually, other scientists began to uncover the truth. Another piece of the cell theory puzzle was identified by Rudolf Virchow in 1855, who stated that all cells are generated by existing cells. At the turn of the century, attention began to shift toward cytogenetics, which aimed to link the study of cells to the study of genetics.

In the 1880s, Walter Sutton and Theodor Boveri were responsible for identifying the chromosome as the hub for heredity —forever linking genetics and cytology. Later discoveries further confirmed and solidified the role of the cell in heredity, such as James Watson and Francis Crick’s studies on the structure of DNA,

  1. The discovery of the cell continued to impact science one hundred years later, with the discovery of stem cells, the undifferentiated cells that have yet to develop into more specialized cells.
  2. Scientists began deriving embryonic stem cells from mice in the 1980s, and in 1998, James Thomson isolated human embryonic stem cells and developed cell lines.

His work was then published in an article in the journal Science, It was later discovered that adult tissues, usually skin, could be reprogrammed into stem cells and then form other cell types. These cells are known as induced pluripotent stem cells,

  1. Stem cells are now used to treat many conditions such as Alzheimer’s and heart disease.
  2. The discovery of the cell has had a far greater impact on science than Hooke could have ever dreamed in 1665.
  3. In addition to giving us a fundamental understanding of the building blocks of all living organisms, the discovery of the cell has led to advances in medical technology and treatment.

Today, scientists are working on personalized medicine, which would allow us to grow stem cells from our very own cells and then use them to understand disease processes. All of this and more grew from a single observation of the cell in a cork.
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Who discovered cells in tree bark?

Born in 1635, Robert Hooke was a member of the Royal Society. He played a pivotal role in the field of biology by visualizing life’s basic unit for the first time using a microscope. He introduced the term cell for the first time after visualizing the bark of the cork tree under a microscope.
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Who discovered the cell from the bark of the tree?

Robert Hooke discovered cell in the year 1665. He observed cork cell in the bark of Spanish oak tree under a simple microscope and was able to see the empty structures surrounded by walls and named it a cell. He elucidated his observation in a book called ‘Micrographia’.
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Where is Robert Hooke’s microscope?

Commentary Images Resources Commentary For his observations, Robert Hooke made use of a compound microscope designed by the London instrument maker Christopher Cock. The first compound microscopes were developed by Galileo and Giuseppe Campani in Italy (1624-1625), and featured three lenses: a bi-convex objective lens placed in the snout and two additional lenses, an eyepiece lens and a field lens fitted in the tube.

  • Cock’s design followed this basic Galilean model.
  • The three of the lenses together offered a good view of a sizeable object, but Hooke found that the resolution was poor: The Microscope,.
  • Was contriv’d with three Glasses; a small Object Glass., a thinner Eye Glass., and a very deep one.: This I made use of only when I had occasion to see much of an Object at once; the middle Glass conveying a very great company of radiating Pencils, which would go another way, and throwing them upon the deep Eye Glass.

To obtain better resolution, Hooke had to remove the middle (field) lens: But when ever I had occasion to examine the small parts of a Body more accurately, I took out the middle Glass, and only made use of one Eye Glass with the Object Glass, for always the fewer the Refractions are, the more bright and clear the Object appears.

  • For illumination purposes, Hooke designed an ingenious method of concentrating light on his specimens.
  • He passed light generated from an oil lamp through a water-filled glass flask to diffuse the light and provide better illumination for the samples.
  • For a three-dimensional view of Hooke’s microscope, see the video embedded below.

Images Image 1. Engraving of Hooke’s microscope, first plate (Schem. I) in Robert Hooke, Micrographia: or, Some physiological descriptions of minute bodies made by magnifying glasses, London: J. Martyn and J. Allestry, 1665. Source: National Library of Wales via Wikimedia,

Copyright: Public domain. Image 2. Full size copy of Robert Hooke’s original compound microscope with illuminating system, probably made by John Mayall in the 1880s and purchased by the Science Museum in 1927. Source: Science Museum, Copyright: CC BY-SA 4.0. Credit : Georgiana Hedesan (June 2018) Additional Resources Material on Hooke’s famous M icrographia (1665) is available here,

Pugliese, Patri (2006), ‘Robert Hooke’, in Oxford Dictionary of National Biography, available freely to Oxford students.
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Was Robert Hooke the first to invent the microscope?

Robert Hooke FRS
c.  1680 Portrait of a Mathematician by Mary Beale, conjectured to be of Hooke but also conjectured to be of Isaac Barrow,
Born 18 July 1635 Freshwater, Isle of Wight, England
Died 3 March 1703 (aged 67) London, England
Resting place St Helen’s Church, Bishopsgate
Nationality English
Alma mater Wadham College, Oxford
Known for Hooke’s law Microscopy Coining the term ‘ cell ‘
Scientific career
Fields Physics and Biology
Institutions University of Oxford
Academic advisors Robert Boyle
Influences Richard Busby
Signature

Robert Hooke FRS (; 18 July 1635 – 3 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of the first two scientists to discover microorganisms in 1665 using a compound microscope that he built himself, the other scientist being Antoni van Leeuwenhoek in 1674.

  1. An impoverished scientific inquirer in young adulthood, he found wealth and esteem by performing over half of the architectural surveys after London’s great fire of 1666,
  2. Hooke was also a member of the Royal Society and since 1662 was its curator of experiments.
  3. Hooke was also Professor of Geometry at Gresham College,

As an assistant to physical scientist Robert Boyle, Hooke built the vacuum pumps used in Boyle’s experiments on gas law, and himself conducted experiments. In 1673, Hooke built the earliest Gregorian telescope, and then he observed the rotations of the planets Mars and Jupiter,

Hooke’s 1665 book Micrographia, in which he coined the term ” cell “, spurred microscopic investigations. Investigating in optics, specifically light refraction, he inferred a wave theory of light, And his is the first recorded hypothesis of heat expanding matter, air’s composition by small particles at larger distances, and heat as energy.

In physics, he approximated experimental confirmation that gravity heeds an inverse square law, and first hypothesised such a relation in planetary motion, too, a principle furthered and formalised by Isaac Newton in Newton’s law of universal gravitation,

Priority over this insight contributed to the rivalry between Hooke and Newton, who thus antagonized Hooke’s legacy. In geology and paleontology, Hooke originated the theory of a terraqueous globe, disputed the literally Biblical view of the Earth’s age, hypothesised the extinction of species, and argued that fossils atop hills and mountains had become elevated by geological processes.

Thus observing microscopic fossils, Hooke presaged the theory of biological evolution, Hooke’s pioneering work in land surveying and in mapmaking aided development of the first modern plan-form map, although his grid-system plan for London was rejected in favour of rebuilding along existing routes.
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How powerful was Hooke’s microscope?

The Father of Microbiology and His Contemporaries – Van Leeuwenhoek’s illustrations of ‘animalcules’ from duckweed. A decade after the publication of Micrographia, Antonie van Leeuwenhoek, a Dutch scientist often referred to as the “Father of Microbiology,” became the first to observe bacteria with a microscope.

His pioneering work in microscopy built on that of Robert Hooke, and helped establish microbiology as a legitimate scientific discipline during the Dutch Golden Age of Science that spanned the 17th century. Spurred by an interest in lens-making, van Leeuwenhoek observed what he called “diertjes,” or “small animals,” in pondwater.

He later documented the appearance of other minute structures and organisms, including muscle fibers, bacteria and red blood cells, using microscopes that he designed and built himself. Although he manufactured at least 25 single-lens scopes, only 9 have survived. One of Van Leeuwenhoek’s microscopes. Van Leeuwenhoek’s microscopes were much smaller than those we use today, and simple in their design, Most consisted of a small lens clamped between 2 flat metal plates, with the complete apparatus measuring around an inch across and 2 inches in length.

The specimen was placed on a pin whose distance from the lens could be adjusted with 2 screws. This basic mode of specimen adjustment is still in use in some microscopes today, although developments have occurred in every other regard. Van Leeuwenhoek never reported his findings in a scientific journal because scientific publishing as we know today did not exist in the 17th century.

Instead, he received publication for some of his hundreds of submitted letters from the Royal Society in London. The first of these letters concerned observations of lice, mold and bees. However, when he wrote to the Royal Society about his first observations of single-celled organisms in late 1676, his reputation was called into question, as nobody knew that such organisms even existed.

  1. Fortunately, van Leeuwenhoek persisted in writing to the Society, and his findings were eventually widely accepted and even celebrated in his lifetime.
  2. Although van Leeuwenhoek gets the credit for first observing and documenting bacteria, others had hypothesized about their existence hundreds of years prior.
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Jain scriptures dated as early as the 6th century B.C. propose the existence of “nigodas,” tiny creatures living everywhere, including in the tissues of plants and animals. As we now know, this is not far from the truth. Scientists the world over also hypothesized that infectious diseases might be caused by invisible agents.

The 14th century Turkish scientist Akshamsaddin described these as “seeds that are so small they cannot be seen, but are alive.” In fact, some argue that a Jesuit priest may have been the first to observe microorganisms, before either Hooke or van Leeuwenhoek. Thanks to his work on projection, Athanasius Kircher was well-acquainted with lenses too; in 1646, he wrote that milk and vinegar were “abound with an innumerable multitude of worms.” Following microscopic examination of plague victims’ blood, he also speculated that the plague was caused by a microorganism, although he most likely observed blood cells rather than Yersinia pestis, the causative bacterium.

Once microorganisms were discovered, the field of microbiology was free to flourish. And flourish it did—the 19th century, in particular, was bursting with microbiological discovery, from Louis Pasteur’s disproving of the theory of spontaneous generation, to Robert Koch’s germ theory and the recognition that hand-washing might prevent infections in medical practice.
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Why is 10X magnification used?

OBJECTIVE LENSES – How does one go about properly selecting an objective for a microscopic task at hand? The first consideration is the type and size of the specimen. What microscopic technique is to be employed and how large do you wish to magnify the specimen? Magnification is fairly simple and straightforward. We all know that 10X means that the objective lens has an effective magnification of ten times life size and when combined in the compound with a 10X ocular lens will give a final magnification of 100X (10 X 10). But what are all the other markings on the lens and how can they help us in selecting the objective lens suited to our needs? This section covers this subject because knowledge of the markings on an objective will give you the information concerning its proper use and whether it is suitable for the microscopic task you have in mind.

  • Lens Type, The first thing that most lenses have is some lettering such as Plan-Neofluar, Plan Fluotar, Planapochromat, Plan or Achroplan. These are all different types of objective which have many glass, fluorite, or quartz elements for light path corrections. The types of lenses listed here are based on the Zeiss objectives as the Facility microscope is a Zeiss LSM 310. However, the names listed here should allow you to determine the type of objective from any manufacturer. If not, you will have to contact the manufacturer to explain the name and markings.
    1. The term Plan stands for flat field. Lenses which are uncorrected for flatness of field will have the center of the field in focus and the outer edges out of focus (or vice versa depending on how you focus the lens). So Plan means the lens is corrected to allow the whole field to be in focus. Achroplans are best for transmitted light while Epiplans are designed for reflected light use. Some microscope manufacturers will list their flat field achromatic lenses as simply “Plan”,
    2. Achromat lenses have good color correction for two wavelenths of light. They are budget priced lenses. Planachromats are achromats with correction for flatness of field as well as the aforementioned color correction.
    3. Plan-Neofluar or Plan-Fluotar lenses are semiapochromatic lenses. They have good color correction for at least three wavelengths and also have the all around flatness of field. They are excellent for polarization microscopic techniques such as differential interference. As they also transmit UV very well, they are excellent lenses for all types of fluorescence microscopy. Any lens with the term fluar in it has fluorite elements in it and all of these are very good for fluorescence work.
    4. Zeiss recently introduced a new line of semiapochromatic lenses named Fluar lenses. These are objectives without a flat field made especially to increase the brightness of fluorescence. The image from a fluar lens is approximately 10% brighter than the equivalent Plan-Neofluar. In the UV range, the light transmission increases by 25-50%. This line of objective lenses was introduced about two years ago.
    5. Apochromatic lenses ( Planapochromat )are the most highly color corrected objectives: they are corrected for four wavelengths and are top of the line in objective lenses. These most often have the highest numerical apertures (see below). Be careful in using these lenses for fluorescence, however. They do not transmit UV light. They work very well for visible light excitation in the blue and green ranges.
  • Immersion, Lenses will be marked for the immersion medium in which they are designed to be used:
    1. ( Oel ) or ( Oil ) for oil.
    2. ( W ) for water immersion.
    3. ( Imm ) Multi-immersion, for oil, water, and glycerin.
  • Phase marking. If the lens has a phase ring and can be used for darkphase illumination, the lens will be marked above the lens type with a ” Ph ” followed by a number corresponding to the manufacturer’s phase ring number system for matching to a ring in the condenser. Phase lenses are generally not as good for fluorescence applications as the light transmission is reduced by the presence phase ring inside the lens.
  • Magnification, As stated before, this is obvious and self-explanatory.
  • Numerical Aperture, After the imprint of the magnification on any quality objective lens, there is usually a slash followed by a number which may be anything from 0.035 to 1.4. This number is the numerical aperture (N.A.) of the lens. This number is directly related to the resolution and second, for those of you doing fluorescence microscopy, it is related to the amount of brightness of the specimen brought into the lens (obviously very important for fluorescence microscopy!) The higher the N.A. of a lens the better its resolving power and the brighter the image it can produce. Resolution is defined as the ability of a lens to distinguish between small objects. Obviously, this differs greatly from magnification which is just the ability of the lens to enlarge the image of an object. It does not mean that you will necessarily be able to resolve details in the object.
  • For a more detailed discussion of numerical aperture and resolution, CLICK HERE,

  • Tube Length and Coverslip Thickness, The marks on the line below the the magnification and the numerical aperture are the tube length/coverslip thickness, The mechanical tube length (between the objective flange and the eyepiece seating face) is normally 160 (in mm) for older objective lenses or ( infinity for infinity-corrected objectives). The number after the slash is the thickness in millimeters of the cover glass for which the objective was designed and corrected. For most objectives for close working distance, this number is 0.17, This designation means that you should use No.1½ coverglasses which range between 0.16 and 0.19 mm in thickness. No.0, 1, and 2 coverglasses are not recommended, Some lenses will have a – sign. This means that the objective is meant to be used with no coverglass. LD (long working distance) objectives may go up to 1.5 mm so that one may look through slides or tissue culture flasks or dishes.
  • Some lenses will also have a rotatable ring which allows one to correct for a coverslip thickness. They are sometimes labelled with “Korr.”
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    What is the most powerful microscope magnification in the world?

    Last Updated on Mar 06 2023 Which Microscope Did Robert Hooke Use To Study Tree Bark Microscopy has come a long way since the invention of the first microscope decades ago. Today, microscopes allow us to magnify a specimen up to 50 million times. As a result, microscopes have become an invaluable tool in science, providing researchers with a way to examine specimens in unprecedented detail.

    • So, which microscope has the highest magnification? Electron microscopes are the most powerful microscopes available today and can magnify a specimen up to 50 million times.
    • Of course, the level of magnification you need will depend on the application you have in mind.
    • However, for most purposes, a lower magnification microscope will suffice.

    Here’s a closer look at the working of electron microscopes and what they can allow you to see.
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    What type of microscope was used to discover cells?

    Seeing Inside Cells – Starting with Robert Hooke in the 1600s, the microscope opened up an amazing new world — the world of life at the level of the cell. As microscopes continued to improve, more discoveries were made about the cells of living things.

    However, by the late 1800s, light microscopes had reached their limit. Objects much smaller than cells, including the structures inside cells, were too small to be seen with even the strongest light microscope. Then, in the 1950s, a new type of the microscope was invented. Called the electron microscope, it used a beam of electrons instead of light to observe extremely small objects.

    With an electron microscope, scientists could finally see the tiny structures inside cells. In fact, they could even see individual molecules and atoms. The electron microscope had a huge impact on biology. It allowed scientists to study organisms at the level of their molecules and led to the emergence of the field of cell biology. Which Microscope Did Robert Hooke Use To Study Tree Bark Figure \(\PageIndex \): An electron microscope produced this image of the structures inside a cell.
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    Which microscope did Antonie van Leeuwenhoek use?

    Antonie van Leeuwenhoek used single-lens microscopes, which he made, to make the first observations of bacteria and protozoa. His extensive research on the growth of small animals such as fleas, mussels, and eels helped disprove the theory of spontaneous generation of life.
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    Where is Robert Hooke’s microscope?

    Commentary Images Resources Commentary For his observations, Robert Hooke made use of a compound microscope designed by the London instrument maker Christopher Cock. The first compound microscopes were developed by Galileo and Giuseppe Campani in Italy (1624-1625), and featured three lenses: a bi-convex objective lens placed in the snout and two additional lenses, an eyepiece lens and a field lens fitted in the tube.

    • Cock’s design followed this basic Galilean model.
    • The three of the lenses together offered a good view of a sizeable object, but Hooke found that the resolution was poor: The Microscope,.
    • Was contriv’d with three Glasses; a small Object Glass., a thinner Eye Glass., and a very deep one.: This I made use of only when I had occasion to see much of an Object at once; the middle Glass conveying a very great company of radiating Pencils, which would go another way, and throwing them upon the deep Eye Glass.

    To obtain better resolution, Hooke had to remove the middle (field) lens: But when ever I had occasion to examine the small parts of a Body more accurately, I took out the middle Glass, and only made use of one Eye Glass with the Object Glass, for always the fewer the Refractions are, the more bright and clear the Object appears.

    For illumination purposes, Hooke designed an ingenious method of concentrating light on his specimens. He passed light generated from an oil lamp through a water-filled glass flask to diffuse the light and provide better illumination for the samples. For a three-dimensional view of Hooke’s microscope, see the video embedded below.

    Images Image 1. Engraving of Hooke’s microscope, first plate (Schem. I) in Robert Hooke, Micrographia: or, Some physiological descriptions of minute bodies made by magnifying glasses, London: J. Martyn and J. Allestry, 1665. Source: National Library of Wales via Wikimedia,

    Copyright: Public domain. Image 2. Full size copy of Robert Hooke’s original compound microscope with illuminating system, probably made by John Mayall in the 1880s and purchased by the Science Museum in 1927. Source: Science Museum, Copyright: CC BY-SA 4.0. Credit : Georgiana Hedesan (June 2018) Additional Resources Material on Hooke’s famous M icrographia (1665) is available here,

    Pugliese, Patri (2006), ‘Robert Hooke’, in Oxford Dictionary of National Biography, available freely to Oxford students.
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    What type of microscope invented by Robert Hooke contained quizlet?

    Who made the first compound microscope? Around 1655 the English scientist Robert Hooke used van Leeuwenhoek’s ideas and made the first compound light microscope, which used more than one lens to magnify an object.
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