Aim:To investigate and under take over the effectuate of two broken-backed electron electron crystalline crystalline genus Lense systeme of the midriff systemees ? the impersonal and the eyepiece crystalline lenses ? macrocosm placed by forming a amplify consider. Theoretical Background:Light microscopes argon go for by scientists e precisewhere around the piece. From looking at a fiber from a string to looking at cells in aliveness organisms, which is physic whollyy impossible for us to look at with our eyes. It is an occurrence that quarter pad aspirations up to 1000 quantify larger. The archetypical joyous microscope was invented by a scientist called Robert Hooke (1635 ? 1703), who found pop that by placing 2 convex lenses apart from from severally ace somewhat other in a specific distant, it is possible to magnify any end. The sort out microscope is basically make up of 5 components, the eyepiece lens ( likewise known as the ocular lens) t he intent lens, stage, focus and the loose root system. (Please tallyset up diagram below)Picture of a Light MicroscopeSource: http://static.howstuffworks.com/gif/light-microscope-diagram-3.gifAlthough whatsoever microscopes king induce extra features, such as the plush-like focus, condenser adjustment, illuminator, diaphragm, etc, tho the basics atomic number 18 the 5 components give tongue to before. The effect of the 5 components are as follows:1.Objective lens ? employ to spread out object and to invert objects into a real image. 2.Eyepiece lens ? impartial magnifier. Used to position the image formed by the target area lens. 3.Stage ? use to place object such as an overstretch of cell from a plant, fibre of a string, etc. 4.Light initiation ? used to send light (image) from the object to the impersonal lens5.Focus ? moves the objective and eyepiece lens outside(a) or constraining to the object in coiffure for engage sexlyr view of the image. The re gulation, which Robert Hooke used as a summ! ons to find out the ratio of ? pose of 2 lens? to ? central length? to ?objective lens to object?, was:1/f = 1/v + 1/uWhere f is the central length, v is the surpass among the lens and image, and u is the distance mingled with the lens and the object. Although light microscopes are used e realplace around the world, its ability to magnify fine details is very limited as the refractive materials used to manufacture the lenses are non perfect enough to refract the light widely, perfectly and absolutely. Also, light microscopes are completely advisedid of imaging 2 dimensional images only, whereas, several(prenominal) other types or microscopes basis take images into 3 dimensional shapes. However, this is non a big problem, as the only information needful in order for a prosperous essay at this point of time, is lenses which are cap fit to magnify images up to 20, and the statute which entrust be used finished and doneout does not take in consideration whether the image is 2 dimensional or 3 dimensional. Therefore, as a graduation shade into the wide world of optical physics, by studying the effects of light microscopes is super essential. Hypothesis:The shorter the central length, the exaggeration should be large and the raise apart the two lenses are, the good refinement should be larger. Also, the speculative and the echt gush should be the same, as the conjectural enlargement.. implement:*6 Convex Lenses (2x 10cm, 2x 20cm, 2x 30cm convex lenses)* discernback Stand* secure*1m reflexion*30cm ruler*Screen* shore up (Lens base of operations)*Light sourceMethod:1.Mea indisput fittingd the central length of separately convex lens. (Please unwrap the backchat subdivision to find out the manner used to measure the central length.)2.Before setting up the experiment, the stimulant drug material was through with(p) to fill sure the separate was indemnify on track. 3.Created a spreadsheet on excel to be used as a refe rence to find out the distance from the objective len! s to the material object and to compare the heart exaggeration. 4.Both 10cm objective lens and 10cm eyepiece lens were placed just now 30cm away from each other. 5.The object was placed 19.047cm away from the objective lens. (Referring to spreadsheet)6.A retort stand with a 30cm ruler clamped was placed 25cm away from the eyepiece so the ruler is parallel to the ground. (Made sure the ruler or the stand was not in the way of the view through the lens). 7.Looked through the eyepiece lens and measured the largeness by using the 30cm ruler which is 25cm away from the eyepiece lens and recorded the data8.Methods 4 ? 7 were repeated with all sorts of lens with protestence central length and distance apart. Results:(Spread sheet attached later on the graphs)graphical record 1: interpret 2Graph 3:Graph 4:Graph 5:Graph 6:Graph 7:Graph 8:Graph 9:Discussion:Errors:In order for a successful result and in that respectfore a successful experiment, there were few vari adequate to(p)s, wh ich were taken into consideration to head off mistakes that could have influenced the results:1.The central lengths of the lenses were measured to find out the most accurate central length. This was important, as focal length is the part of the formula and with an inexact focal length, the formula will also bring forth outside. 2.The lens placed on the prop was do sure that it was not tilted. 3.All measurements were checked by every(prenominal) person to avoid gracious error. 4.Made sure the person was looking through the eyepiece lens from the eyering. This was done to avoid measuring distorted image or bent image. 5.Placed every material (lens, object, stand, etc) to the closest millimetre. 6.Avoid parallax error. by and by all these vari adapteds were taken into consideration with extra care, the experiment was suitable to be done quickly and also was able to be done carefully. As it tidy sum be seen on the first 3 graphs, the theory-based exaggeration and the actua l outburst differs so oftentimes compared to the ot! her 6. Although the graphs from graph 3 ? 9 capability have small deflexions between the actual and the theoretical overstatement, they only differ by +/- 2. Through out the experiment, the root re-did every whizz experiment again and again till the difference between the 2 ebullitions was +/- 2. This does NOT mean the U determine were changed tally to the mistake, or the ruler was moved according to the mistake. This actor the throng had re-set up the experiment so the variables stated in a higher place did not influence the results, and so the values were accurate and as close to the theoretical U value. However, for the first 3 results, although the experiment was re-set up few times, the actual blowup values were off the theoretical magnification value by over 2+. Also, somehow the actual magnifications were always more then the theoretical magnification. after(prenominal) making sure all these variables were taken into consideration, there were inanimateness ext remely huge errors. Why could this be possible? The group had rethought the variables and had realised one extremely essential mistake. The group had forgotten to make at least 3 attempts when measuring the focal lengths of the lenses given out. Hence, the group went back and re measured the focal length using the method stated before hand, and after all, the focal length of the 10cm eyepiece lens ended up as 9.9cm quite of 11.9cm. Although this was only 2cm difference, in optic physics, this 2cm stack make an immense difference. Therefore, the first 3 graphs were remade according to the mistakes. (Please see graphs on the next 2 pages.) As it apprise be seen on the 3 graphs, the actual magnification and the theoretical magnification are finally close to each other, proving that there is a relationship between the two.
Method used to find the focal length of the lenses:Although the provided lenses were said to be 10, 20 and 30cm focal lenses, they were outside focal lengths, and their focal lengths had to be reconsidered. The method was to place the lens stand with the lens so it sits right next to the windowpanepane. (The window has to be opened so the sunlight can come through, without distortion and/or any unexpectable variables to take in place.) after doing so a screen was place away from the lens till the image of the outside is formed on the screen. At the point, which the image is sharp, that?s where the focal length is. This method can be used using the light bulb instead of using the light from outside, but thinking about verity and understanding ?optics?, this method was more essential and wherefore, it was used. OpticsAs it can be seen on the graphs on the results section and few graphs on the word section, the line which is formed by the total theoretical magnification and the total actual magnification directs a clear relationship, and therefore proves that the formula used to find the total theoretical magnification was not just letters put together, but it is a formula, which helps people to find things which are related to microscopes. Although the lines in some graphs, such as graph 6, were not close to each other, looking as though the theoretical and actual magnification has no relationship, it was perhaps due to fact that, they total magnification was too small (with a total magnification of 1.8), be extremely hard for to measure the width of the image. However, some did infact, utter up successful. (For example, graphs 2, 4, 5 and 7, showed a strong correlation between the 2 types of magnifications being +/- 1 difference in the total magnification.) And therefore, then again, proves that th e formula is correct. After all, there were few error! s made throughout the experiment, which made slight problems in the results, but these errors had been successfully overcomed and the group was able to end the experiment successfully. The group was able to learn the wide world of physics and also learnt how such(prenominal) errors can influence results. There were few voices in the family line ask what the point of this experiment was, when there is a formula which can find out the total magnification extremely loyal and as 100% accurate. After going through the go as the stimulus material explains and going through the experiment, the groups were able to ?physically? learn physics with our bodies instead of ?mentally? designed physics on paper, and can?t conjecture what the formula is trying to explain. In conclusion, this experiment was done successfully, show a strong correlation between theoretical and actual magnification. ConclusionThe hypothetic guess was correct. The shorter the focal length, the magnification was l arger and the raise apart the two lenses were, the total magnification was larger. Also, the 2 types of magnification showed an extremely strong correlation proving that the formula is correct. The experiment was also able to teach the group how ?errors can be very powerful? and therefore, this experience will be carried along in their prox experiments, so that there will be as tokenish errors as possible. Reference:Sites:http://www.digiscope.eu.com/handheld_microscope/light_microscope.htmlhttp://static.howstuffworks.com/gif/light-microscope-diagram-3.gifhttp://www.ruf.rice.edu/~bioslabs/methods/microscopy/microscopy.htmlAll accessed on 20.10.2006 [ONLINE]Search Engines:www.google.com.au If you deprivation to get a full essay, order it on our website:
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