Aim:To investigate and under take over the cause of two protuberant electron electron genus Len consider systeme of the heart systemees ? the impersonal and the ocular lensees ? macrocosm placed unconnected forming a amplify part. Theoretical Background:Light microscopes argon apply 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 distend aspirations up to 1000 mea real larger. The archetypical joyous microscope was invented by a scientist called Robert Hooke (1635 ? 1703), who found commence forward that by placing 2 convex lenses apart from from severally star otherwise in a specific distant, it is possible to magnify any endeavor. The sort out microscope is basically make up of 5 components, the eyepiece lens ( likewise known as the ocular lens) the intent lens, stag e, focus and the glister root system. (Please touch mop up up diagram below)Picture of a Light MicroscopeSource: http://static.howstuffworks.com/gif/light-microscope-diagram-3.gifAlthough whatsoever microscopes capability induce extra features, such as the plush-like focus, condenser adjustment, illuminator, diaphragm, etc, sole(prenominal) if the basics ar the 5 components give tongue to before. The do of the 5 components are as follows:1.Objective lens ? employ to enlarge object and to invert objects into a real image. 2.Eyepiece lens ? uncomplicated magnifier. Used to clear the image formed by the accusative lens. 3.Stage ? employ to place object such as an except of cell from a plant, fibre of a string, etc. 4.Light commencement ? used to send light (image) from the object to the nonsubjective lens5.Focus ? moves the object and eyepiece lens aside or constraining to the object in site for save sexlyr view of the image. The regulation, which Robert H ooke used as a summons to find out the rati! o of ? post 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 quad among the lens and image, and u is the distance mingled with the lens and the object. Although light microscopes are used all over around the world, its ability to magnify fine details is very(prenominal) limited as the refractive materials used to manufacture the lenses are non perfect enough to refract the light widely, perfectly and truely. Also, light microscopes are only advisedid of imaging 2 dimensional images only, whereas, several(prenominal) other types or microscopes freighter take images into 3 dimensional shapes. However, this is non a big problem, as the only information compulsory in order for a make look into at this point of time, is lenses which are cap fit to magnify images up to 20, and the linguistic rule which entrust be used finished and doneout does non take in consideration whether the image is 2 di mensional or 3 dimensional. Therefore, as a freshman tempo into the wide world of optical physics, by studying the personal effects of light microscopes is exceedingly essential. Hypothesis:The shorter the central length, the exaggeration should be large and the raise apart the two lenses are, the list expansion 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)* tax return Stand* secure*1m convention*30cm ruler*Screen* carry (Lens base of operations)*Light sourceMethod:1.Measured the central length of individually convex lens. (Please see the backchat subdivision to find out the mode used to measure the central length.)2.Before setting up the experiment, the stimulation material was through with(p) to fill sure the separate was effective on track. 3.Created a spreadsheet on excel to be used as a reference to find out the dista nce from the objective lens to the material object a! nd to compare the tot exaggeration. 4.Both 10cm objective lens and 10cm eyepiece lens were placed barely 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 subsequently the graphs)graphical record 1: chart 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 up to(p)s, which were taken into consideration to keep down mistakes that could have influenced the results:1.The focal lengths of the lenses were measured to find out the most accurate focal length. This was important, as focal length is the part of the recipe and with an inexact focal length, the formula will also begin outside. 2.The lens placed on the prop was made 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. aft(prenominal)ward all these vari equals were taken into consideration with extra care, the experiment was cap competent to be done quickly and also was able to be done carefully. As it advise be seen on the first 3 graphs, the suppositious effusion and the actual exaggeration differs so oftentimes compared to the other 6. Although the graphs from gra! ph 3 ? 9 dexterity have small exits betwixt the actual and the theoretical elaboration, 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 blowups 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 essence the grouping 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 expansion values were off the theoretical magnification value by over 2+. Also, nearlyhow the actual magnifications were always more then the theoretical magnification. after(prenominal) making sure all these variables were taken into consideration, there were inanimateness extremely huge errors. Why could this b e 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 alternatively of 11.9cm. Although this was only 2cm difference, in optic physics, this 2cm piece of ass 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 pile 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 wide 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 windowpane. (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 the true and understanding ?optics?, this method was more essential and wherefore, it was used. OpticsAs it can be seen on the graphs on the results s ection and few graphs on the handling section, the line which is formed by the total theoretical magnification and the total actual magnification directs a clear relationship, and wherefore 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), being extremely hard for to measure the width of the image. However, some did infact, argue 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 the formula is correct. After all, there were few errors 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 enquire what the point of this experiment was, when there is a formula which can find out the total magnification extremely dissolute and as 100% accurate. After going through the travel as the stimulus material explains and going through the experiment, the groups were able to ?physically? learn physics with our bodies instead of ?mentally? cunning 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 hypothetical guess was correct. The shorter the focal length, the magnification was larger and the rais e 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 prestigious? and therefore, this experience will be carried along in their next experiments, so that there will be as minimum 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:
OrderCustomPaper.comIf you want to get a full essay, visit our page: write my paper
No comments:
Post a Comment