1. Formulation of Questions and Hypotheses. This experiment has always been a question of mine, from watching movies to seeing

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1 Background Information: This experiment has always been a question of mine, from watching movies to seeing people try it I have always wondered. When watching Survivor in the beginning of the season they had no fire and had to find a way to start one. I always thought why not take the glasses off of one of the members and start a fire with them. I have not seen it done they always wait till they get flint. Then when I was little and being babysat an older kid decided to take a magnifying glass outside and see if he could start a fire, but nothing happened. Did he do something wrong? Was it not strong enough? Not close or far away enough? These were all things I have wondered but never been able to test until now. We have known about lenses for a long time now. At the archaeological Museum in Heraklion, Crete, there is a Minoan rock crystal hand lens that is dated all the back to 2000 BC. The Middle East discovered the ability of a pinhole to form an inverted image, this occurred in second century AD. Soon someone discovered that if you put a lens over the enlarged pinhole, which combined the images to enlarge it further more. The iris was created by Sir Christopher Wren. Sir Christopher Wren was the professor of astronomy at Oxford from 1660 until Niepce, Daguerre, and Talbot along with many other individuals were the first to create an experiment that involves photography. The used simple double lenses, but this causes the image to become blurry towards the edge of the field. In 1812 William Wollaston created the meniscus lens. This was a convex lens on one side and concave on the other. There was a stop in front of the concave side which allowed for good definition at f/11 over a field angle of 45 degrees. This lens was then widely and commonly used in Kodak Brownie camera until about the late 1930 s. To minimize chromatic aberration Chevalier designed the achromat in the year The achromat blanched out the color dispersion due to a weak negative lens

2 made of glass that had a high dispersion. Early cameras were only sensitive to blue but it did not affect the overall image, the achromats were matched in blue and yellow wavelengths since the eye is more sensitive to yellow. Simple lenses or achromats suffer from spherical aberration. Spherical aberration is a defect that is caused by the outer zone of the lens having a shorter focal length than the inner zones. This can be corrected by the use of a small stop. In the late 19 and 20 th centuries the pictorialists felt a need for the soft-focus effect. This measured the spherical aberration fulfilled admirably. Come to find out that a lens called aplanats could minimize spherical aberration by carefully chose of curvatures from various surfaces of the lenses. In 1841 Josef Petzval made the first most important advancement in photography, which he computed mathematically. This object contained 4 single lenses; two of them formed a cemented doublet and covered a field of about 25 degrees at an aperture of f/3.6. This represented almost a thirty fold improvement in image illuminate and reducing daguerreotype exposures for twenty minutes or more as well as less than a minuet. The increasing the size of the image by f/2.4 was created by Voigtlander and Steinheil. Millions of these lenses were purchased for about 60 years, and can even be found in some slide projectors. In the mid 1850s a much faster wet-collodion plates become more favorable. At this point the need for photographic recorded of architectural, industrial, and science subjects was reaching the point of being required. The orthoscopic lens, this lens is concerned with curvilinear distortion which is a result in the outer parts of the image being stretched out or punched inward. Steinhiel solved the problem by dividing the lens. The lens was divided symmetrical with the stop in the middle in By using the wide-angle lenses were developed. The Goerz Hypergon is one of the more extreme versions; this one is a completely spherical profile and covers 120 degrees at f/22.

3 Dallmeyer and Steinhiel in 1866 designed the Rapid Rectilinear lens. The Rapid Rectilinear lens consists of two achromatic doublets facing one another with in a central stop. The only eye problem not under control was astigmatism. This lens covers a field of 53 degrees at f/8, which became the standard lens in amateur cameras. The next big thing was the elimination of astigmatism. It now became possible to correct this problem by using the fix existing types of optical glasses that are available Abbe and Schott developed an entirely new series of glasses that incorporated barium; which allowed for different ranges of values of refractive index and dispersion in England Dennis Taylor made this format simpler by separating the lens components to produce the Cooke triplet lens, this gave a negative elements between two positive elements. The central element was split into two pieces which provided a symmetrical lens. This lens became known as the standard long-focus lens for aerial photography; which was the creation of Cooke Aviar. In the year 1902 Rudolph added another element by adding a triplet design which created the immensely successful Zeiss Tessar lens with an aperture of f/4; this lens was produced for over 80 years after this time. In the 1950s lenses had been pushed beyond all known measurers. Been soon many designers began to create the zoom lens. The computer began to have a significant impact on the lens industry because it could cut 6 months of work down to about one or two days of work with more accuracy. The next advancement to help out lens designers was the optical transfer function; this allowed to go beyond the parameters of resolving power and acutance to define the lens performance at all spatial frequencies. Fabrication techniques went on to include computer-controlled machinery; using diamond tools. Many objects in our everyday life would not operate without lenses, and many people would not be able to see either. Some of those objects are:

4 A camera is an object that is able to capture the moments by taking a picture. A camera consists of a lens and sensitive film that is mounted in a lightning box. Many cameras can change the distance of the lens and the film because the lens is mounted in a screw mount which allows it to follow a to and fro pattern. The film then forms a real, inverted image on the film. The majority of cameras use a single simple lens because it allows for less distortion which is called aberration. Aberration is the unavoidable distortion in an image produced by a lens. The next step comes with the shutter and the diaphragm. The shutter and the diaphragm regulate the amount of light that enters and makes contact with the film. The shutter controls the time that the light and film are in contact, and the diaphragm controls the opening which the light passes through in order to reach the film. Compound microscopes use two short length diverging lenses. The first lens is called the object lens. An object lens produced a real image of the close object. The object becomes enlarges because it is farther away form the lens than the object. The second piece is called the eye piece, which forms a vertical image of the intended object, and causes even more enlargement. The entire device is called a compound microscope because it causes the image to enlarge which was enlarged to begin with. A telescope uses a lens to allow it to form a real image of a distance object. The real image is projected into space to be captured by another lens which is used as a magnifying glass; the real image is not caught on film. The eyepiece is the second lens in the telescope. It is positioned so that the image produced by the first lens is created within one focal length. It is due to the eyepiece that we can see the object because it enlarges the image vertically so the real image can be seen. A telescope acts in a way like a mirror because when you look into a telescope you are seeing the image of an image. A third lens is then used or a pair of reflecting prisms are used in the terrestrial telescope. The terrestrial telescope will produce

5 an image that is right side up. If you place to of these objects together you will get a large version of binoculars. The lenses in a projector or movie projector are considered to be concave. A concave mirror reflects light from an intense source back onto a pair of condenser lenses. The condenser lenses direct the light through the slide or movie frame to a projection lens. The projection lens is mounted in a sliding tube so that it can be positioned to or fro to focus a sharp image on the screen which makes it easier to see. If you are a person with farsighted vision form the images behind the retina. This is because the eyeball is shorter than normal. On average a person with farsighted vision must hold things about 25 cm away from there face in order for the object to become focused. In order to correct this problem doctors increase the converging effects of the eye. This can be achieved by wearing glasses or contacts with converging lenses. Converging lenses will converge the rays that enter the eye sufficiently so that the objects will focus on the retina instead of behind it. If you are a person that has nearsided vision you only can see things that are near by. You can not focus on far away images because the object focuses too near the lens, in front of the retina. Unlike farsightedness when the eye is to short, the opposite applies to nearsightedness and the eye is to long. The only way to correct this problem is to ware glasses or contacts that have lenses that diverge the rays from distant objects so that they focus on the retina instead of in front of it. Astigmatism occurs when the defect results when the cornea is curved more in one direction than the other. This causes the eye to see images without complete and under sharpness and clarity. To fix this problem a person must use a cylindrical corrective lens that has more curvature in one direction than in another. There are numerous types of lenses throughout the world. Some of these varieties are but not limited to:

6 The convex lens is the most commonly used lens. This lens is used for examination of small object up close. The rays of light that may approach the lens are parallel to each other. When the rays reach the glass surface and then began to refract according to the effective angle of incidence at the point that each ray reaches the surface. It then refracts according to the effective angle as well according to the incidence at the point of lens. Since most lenses are curved, rays will diffract differently at different degrees; the outermost rays cause the most refraction. When the rays exit the glass, they encounter a curved surface as well which causes refraction once again. The rays then bend more profoundly towards the centerline of the lens. Concave lenses are lenses that posses one surface that curves inward. Because of the inward curve the rays spread out when they have been penetrated through the lens. A concave lens is thinner at its centre that at its edge and is often used to correct shortsightedness. When rays go through the lens they come form the principal focus. The focal length id defined as the distance between the principle focus and the lens. The image created by a convex lens cannot be projected onto a screen because it is vertical and upright as well as smaller than the original object or item. There is a lens formula which is 1/u + 1/v = 1/f; which is used to find out the position and nature of the image that is formed after it enters the lens. U and v are the distance of the object and image form the lens as well as f which is the focal length of the lens. A converging is classified as a lens that is thicker in the center. One of the edges is typically a convex but will function like a converging lens when it is operated in air. When rays enter the lens parallel to each other and to its axis are brought to focus at the principal focus. This position can be located behind the lens. The secondary focus is similar to the principle focus but is the same distance in front of the lens. The focal length is the distance from the center of the lens to the principal focus; this is normally displayed by the variable f. The rays

7 of light are refract the lens converging behind the lens to form an image. This kind of image is considered to be a real image. Real images are the type of images that can be projected or displayed on a screen. Real images are also known as hot images. Diverging lenses are thinner in there center; the edges are considered to be concave lenses; but act as diverging lenses when in the presence of air. The rays enter the lens parallel to the axis and are brought to a focus in front of the lens this is also called the principle focus. Similarly to the converging lenses the secondary focus applies here as well. The rays of light enter a diverging lens the image forms at the intersection behind the lens. This is called a virtual image. Virtual images are upright and trapped inside the lens. Since the rays of light do not form this image it is considered to be a cool image. These images can not be projected onto a screen through a projector, slideshow, or movie. Lenses have not only stood the test of time but also have adapted to fit our needs. The things that we have today would have never been fathomed in past years. The future has so much potential and so much in store for us that can only be imagined. How knows what the next advancement in lenses will be? Whatever it is it will change our lives and the world as we know it. Question: - What if there is no sun? - Does the strength matter? - Can glass work? - Does the distance affect the ability to produce a fire? - Does humidity or climate affect it as well? - Can a fire be produced through the lenses of a window indoors?

8 Hypothesis: I think that only the strong lenses will be able to produce enough to start a fire as seen in the movies, I think that the reading glasses will not be able to as well as the two smaller powered magnifying glasses. Objective: To see how much magnification is needed to produce a fire with using only the sun, as seen in many movies. Bibliography: - - I used this website that I used to figure out how to test my idea I used this website to figure out about the history of lenses I used this website to also find out more about the history of lenses. -Hewitt, P.G. (Ed.). (1987). Conceptual physics. Menlo Park, CA: Addison-Wesley - I used this book to find out applications of lenses.

9 - - I used this website to understand the development of lenses I used this website to find out about convex lenses I used this website to find out about concave lenses. - onverginglenses.xml -I used this website to find out about converging lenses. - verginglenses.xml - I used this website to find out about diverging lenses.