Missing Figures
Imagine this, you are walking through the forest when all of a sudden you come across the most fascinating insect (perhaps insects may not seem too fascinating at first but once you learn a little about them they are the most fascinating creatures). Well, back to the story, so you find this insect and you realize that it seems very different from those you've previously encountered. Well, being the curious scientist that you are, you take out your trusty magnifying glass and take a look. You move the lens back and forth until you find the perfect image. You see the insect's wonderful colours and patterns which you would not be able to see with your naked eye. What just happened? You simply placed a piece of glass between you and the insect and all of a sudden you get this wonderful view of nature which would otherwise be missed. Well, if you are at all curious as to know how magnifying glasses and microscopes work, then read on and find out.
An Introduction to Microscopes
The two types of microscopes that will be focused on in this webpage are the simple microscope and the compound microscope. The simple microscope, also known as the magnifying glass, is composed of a single converging lens. The compound microscope is composed of at least two lenses and is generally referred to as a microscope.
There are two main purposes of a microscope:
1) to increase the magnification of an object
2) to have a high resolving power
Both of these will be examined; however, a greater emphasis will be placed on the resolving power.
Magnifying Power (brief overview)
Magnifying power: is also called angular magnification. Figure 1a shows an object y in front of a lens. Rays of light reflect off the object through the lens and a now larger image, y', of y can be seen. Once, the image is brought further from the lens, as in figure 1b, the image, y', is even larger. (So as to no discrepency: in figures 1a and 1b, the observer is on the right of the lens looking towards the image y')
The magnifying power, M, is given by the following:
M = 1 + d/f, where f is the focal distance and d is the distance between the object and the lens
Proof of M = 1 + d/f:
Figure 1c is the view of the object Y from point C without a magnifying glass.
...ossessed with three dimensional attributes. The optical effect may be explained by the fact that the human eyes see an object from two viewpoints separated laterally by about six centimeters. The two views show slightly different spatial relationships between near and near distant objects and the visual process fuses these stereoscopic views to a single three dimensional impression. The same parallax view of an object may be experienced upon reflection of an object seen from a concave mirror." (http://www.freepatentsonline.com/4229761.html).
One can almost feel the searing penetration of Lewis Thomas’ analytical eye as it descends the narrow barrel of the microscope and explodes onto a scene of vigorous, animated, interactive little cells—cells inescapably engrossed in relaying messages to one another with every bump and bounce; with every brush of the elbow, lick of the stamp, and click of the mouse…
The answers of many questions that trouble us can be found by doing first hand investigations. In science, first hand investigations allow scientists to discover new things and explain old things. Through these, they are able to form hypothesises, models, experiments, theories and even laws.
For the light microscope this distance is approximately 0.2µm. So in theory it might seem possible to magnify an object indefinitely by means of glass lenses in series. This has been put into practice and has only produced a larger and fuzzier picture; so the resolution is not improved and no more detail is visible. The resolution of the light microscope is imposed by the wavelength of visible light, and means that little is gained by magnifying an object more than 1500 times. This limits the amount of structural detail that can be seen within a cell.
In the early 1400s, Italian engineer and architect, Filippo Brunelleschi, rediscovered the system of perspective as a mathematical technique to replicate depth and form within a picture plane. According to the principles, establishing one or more vanishing points can enable an artist to draw the parallels of an object to recede and converge, thus disappearing into a “distance”. In 1412, Brunelleschi demonstrated this technique to the public when he used a picture of the Florence Baptistery painted on a panel with a small hole in the centre.3 In his other hand, he held a mirror to reflect the painting itself, in which the reflected view seen through the hole depicted the correct perspective of the baptistery. It was confirmed that the image
In 1802, philosopher William Paley called the eye a miracle of "design". Your eyes are responsible for 80 percent of all of the information that your brain receives. (Schleifer, 2014) But how did our eyes form? How are we able to see what we see? What allows us to see the colors we see? The eye is made up of many different complex parts that all work together to create images our brain can understand. The eye is made up of the front parts, or parts we can see, the interior parts, or parts we can’t see, the nerves which carry signals to our brain, and glands that protect our eyes. The eyes we have today have evolved over a long period of time and undergone many different changes, according to Charles Darwin, Richard Dawkins, and many other evolutionists. When all of the different parts of our eyes work together we are able to see a clear image that is produced from our brain.
''These two approaches can be compared to a telescope. One end will show everything in enlarged form and in great detail (the microview), the other will display a world that is small and distant (the macroview). Both are 'true' pictures of the same thing.''
Binoculars - A tool you look into used to make things look closer than they are so you can see it more clearly.
The human eye’s ability to view focused images of both nearby and distant objects is dependent upon its capacity to accommodate. When you want to look at something nearby, the lens in your eye assumes a large curvature, resulting in a shorter focal length. Conversely, your lens becomes flatter in shape and takes on a longer focal length when you want to look at a distant object. Accommodation is key in allowing your eyes to use its muscles to change focal lengths in order to see objects at a variety of distances. When you lose the ability to accommodate, the lenses in your eyes become locked to focus on either near or far away objects. In the case of nearsighted individuals, light entering the eye can only focus on objects nearby. As a result, distant objects appear blurry because light is focused in front of the retina, or the light-sensitive tissue layer at the back of the eye, instead of directly on it.
The four main components of the eye that are responsible for producing an image are the cornea, lens, ciliary muscles and retina. Incoming light rays first encounter the cornea. The bulging shape of the cornea causes it to refract light similar to a convex lens. Because of the great difference in optical density between the air and the corneal material and because of the shape of the cornea, most of the refraction to incoming light rays takes place here. Light rays then pass through the pupil, and then onto the lens. A small amount of additional refraction takes place here as the light rays are "fine tuned" so that they focus on the retina.
...isual attention within and around the field of focal attention: A zoom lens model. Attention, Perception, & Psychophysics, 40(4): 225-240.
Light rays gather through the opening of the telescope called the aperture and pass through the objective lens and refract onto a single point called the focal point. From there, the light rays continue in the same direction until it hits the eyepiece lens, which also refracts the light back into parallel rays. During the process, the image that enters our eyes is actually reverse of the original image and magnified because of the size in which we perceive the image.
Perspective has its roots in Latin it comes from the word ‘perspicere’ or translates literally as ‘to see clearly.’
In addition to this use of models, the natural sciences also use models to illustrate observations. When looking through a microscope one would need to model the cell or any such microscopic being, however it is impossible, as well as illogical, to grab wha...
The refracting telescope is one of many different types of telescope. Refracting telescopes work by refracting the light through an initial convex lens, (known as the objective lens), then through another convex lens (known as the eyepiece lens). These two lenses focus the light into the eyepiece so we can see the image clearly.