Thames & Kosmos TK2 Scope, Experiment Manual

Page 1: ...Experiment Manual ...

Page 2: ...nmental regulations Never short circuit the terminals of the battery or of the battery holder A short circuit can lead to the overheating of wires or to the exploding of the batteries Make absolutely sure that no batteries are placed together for example with coins a key chain or other metallic objects Do not throw batteries into fire Avoid deformation of the batteries Caution Certain parts of thi...

Page 3: ...Experiment Manual by Jan Haller and Chris Scrogum Thames Kosmos LLC Portsmouth RI USA Franckh Kosmos Verlags GmbH Co KG Stuttgart Germany ...

Page 4: ...and other tricks 37 13 Leaf by Leaf Task Distribution The structure of leaves and tasks of the tissues 41 14 Hair Raising Sites Animal and plant hairs under the microscope 44 15 Even Smaller and Finer About electron microscopes 47 What s Included in Your Microscope Kit 1 Microscope with ocular lens Caution The ocular lens sits loosely Heed the tip on page 5 2 Plastic box with Permanent prepared sl...

Page 5: ...p you Cover slips break easily and then have sharp edges 4 In some experiments stain solutions and other household chemicals iodine solution nail polish are used Be sure to heed the warnings of the manufacturer Handle the liquids with caution and care and close the containers immediately after use It s best that you have your parents lend you a hand with these experiments 5 If foods are required f...

Page 6: ... es between elephant cells and carrot cells What makes up the strong frame of the elephant Are its cells larger or does it simply have more cells than a carrot to form its trunk ears and belly These are just a few of the endless number of questions that you can investigate and answer with your new microscope An elephant will most likely not fit under the microscope But you will definitely be able ...

Page 7: ...icroscope You may be asking yourself microscope magnifying glass what s the difference really This will become clear as you read the following two sections Let s start with the simpler of the two types of viewing modes the magnifying glass The Microscope as a Magnifying Glass When observing an object under a magnifying glass we use the light that falls onto the object from above such as from the s...

Page 8: ...ise so that the yellow objective 10x is pointing downward perpendicularly and focus the image again You ll see that the area in which you see a clear image at this ten fold magnification has become much smaller and that you had to move the objective lens closer to the object Consequently when examining thick and above all even hard objects e g rocks crystals coins etc you have to be very careful n...

Page 9: ...ever it is that you happen to be looking at in that moment is destroyed 2 The sensitive lens on the underside of the objective can be scratched and in the best case scenario from now on you will always see these scratches In the worst case scenario you will not be able to see anything clearly through the scratched objective If the objective lenses should get dirty at some point then clean them car...

Page 10: ...ng in the different magnifications of the object Instead of changing the shape of the lens to achieve higher magnifications how ever it is also possible to simply use several lenses in series In your microscope there are two lenses in the objective and one in the ocular So in effect you are looking at the image enlarged by the objective with a magnifying glass ocular You get the total magnificatio...

Page 11: ...de is included in the set It has a small recess a concave trough in the middle You might use this slide when you want to look at larger objects under the microscope for example amphipoda from a pond In any case it will be of great help to you in the experiments described in Chapter 7 The use of the tweezers surely needs no special explanation How they are used in conjunction with the microscope as...

Page 12: ... with which only very certain structures e g cell nucleus cell wall or the like are stained If you look on the internet under the search terms microscopy and staining methods you will find lots of interesting tips on the staining of preparations But it s also a good idea to simply experiment with household items Red and blue dye correspond ing to the microscopic stain reagents eosin red and methyl...

Page 13: ...d the razor blade by the cork grip Paper tissues or paper towels are useful for wiping up liquids or rubbing the slides dry They are also used to absorb liquids under the cover slip see Chapters 4 and 5 although a piece of blotter paper can prove useful for this too When using staining solutions follow the safety precautions on page 3 To produce thin slices a cutting aid is often needed see also C...

Page 14: ...has very specialized tasks to per form In fact every part of the body generally has several tasks to perform at the same time For example the skin has a number of duties to fulfill It is our outer wall and has to prevent undesired intruders such as pathogens or toxic substances from penetrating onto our grounds After a 100 meter sprint the skin has a different function It sweats and hence prevents...

Page 15: ...easy for you What do you do if there is too little or too much water under the cover slip The space between the cover slip and the slide should be completely filled with liquid It s possible that the drop that you dabbed onto the slide initially was too small so that there is no water under the cover slip at the edges That s undesirable since parts of your object could dry out and then not pro duc...

Page 16: ...ll find a description of this permanent preparation in Chapter 16 It Depends on the Function Onion Cells Onion cells are good examples of typical plant cells that can be obtained very easily for observation under the microscope For this you will need a slide and a cover slip the pipette and water a quarter of a cooking onion a razor blade see page 11 the tweezers Peel the onion and take one of the...

Page 17: ...now How to Stay in Shape Although a plant loses water it retains its shape for some time afterward This is because plant cells in contrast to animal cells are surrounded by two cover ings and not by just one The Cell Membrane Both animal and plant cells are enclosed by a so called cell membrane This cell membrane is like a skin that protects the cell from intruders But strangely this cell skin is ...

Page 18: ...To do this however you don t need to lift the cover slip each time There s a more elegant way The method for drawing excess water out from under the cover slip was explained in the introduction You can apply the same technique in order to suck another liquid under the cover slip Simply dab a drop of the liquid e g the stain onto the slide next to the cover slip and suck it up under the cover slip ...

Page 19: ...es as food for a plant eater But where does the plant get its life energy Plants are special organisms because they can do something that only they and a few bacteria are capable of Plants use the energy of the sun Just imagine spending two hours in the sun each day and being nourished for the rest of the day That would be fantastic All of the world s nutritional problems would be solved if we wer...

Page 20: ...n as long as they are unripe Apples tomatoes cherries or grapes change their color over the course of ripening Through the altered color often supported by emitted aromas the plant signals that its ripened fruits are now suitable for consumption Why does it do that To have the seeds hidden in their fruits distributed by animals of course They eat the seeds with the fruits are not able to digest th...

Page 21: ...dition They need to be thin enough so that light is able to pass through them As a rule excessively thick specimens do not let enough let through and they also usually contain several layers of cells on top of each other This makes it very difficult to see anything clearly Cutting is an art in and of itself and the preparation of good thin cuts is prob ably not going to come to you or anyone else ...

Page 22: ...d to as wheat corn or potato starch You can perform a simple test for what foods still contain starch using iodine solu tion Iodine and starch result in a deep blue coloring If a lot of starch is present such as in flour or in potatoes then the color is so intense that it looks almost black You should not eat the food after the test Starch is stored in plant cells in the form of so called starch g...

Page 23: ...the highest magnification 400x Repeat the experiment after a few days In the meantime the rest of the banana has ripened Examine the ripened banana as described above and compare the results The Starch Leaves and Sweetness Follows Perhaps you ve seen a potato that has been waiting too long to be cooked Pale yellow sprouts grow out of the tuber from which entire potato plants would grow if the pota...

Page 24: ... and is therefore mostly germ and microbe free The obser vations begin to get interesting when you are looking at waters that don t exactly entice one to bathe in them ponds and puddles with green alga growth offer a true paradise for interesting creatures to investigate You can take samples from the water in a number of different ways Just like in the human world the inhabitants of lakes and pond...

Page 25: ...mple with rocks or sand and tie it closed at the top using the string The string needs to be long enough so that it reaches from the bottom of the pond or water barrel wherever your plastic bag anchor will be lying up to the surface So simply measure the depth using a stick add another 30 centimeters to be on the safe side and cut the string accordingly Now the glass slides are stuck into the cork...

Page 26: ...e living space is coming along Are there suddenly new species that you hadn t encountered before Do some species eventually disappear from the picture over the course of time A typical inhabitant of such hay infusions is for example the paramecium of which you will also find a few stained specimens on a prepared slide in your kit The name of this creature which measures from 50 to a maximum of 300...

Page 27: ...ge from a flower dusted from head to toe with yellow pollen so it s no wonder that a grain or two of pollen ends up getting into the honey But all pollen grains are not the same The round thorny pollen of a sunflower for example looks completely different than the pollen of a pine or a spruce which has air sacks Some examples of how different pollen grains look can be found on this page and on one...

Page 28: ... drop of the cloudy solution onto the slide and off you go Examine the honey solution at different magnifications and find out how many different types of pollen there are Maybe you can even match some of the pollen types to a plant species if you compare them to the overview on the previous page After concluding your investigations you should dispose of the honey solution in a drain It is neither...

Page 29: ...d you will be able to see a white crust with the naked eye where the clear water drops had been Under the microscope however the crust turns out to be a crystal garden With some luck you ll find some larger crystals that are as nicely formed as the ones in the prepared slide Another tip The slower the water evaporates the greater the possibility of beautiful crystals forming So it s not a good ide...

Page 30: ... insects probably the most important reason for this becomes clear Delicate lines run through the filigree wings of insects the wing veins In some insect orders such as the butterflies for example these are only covered by scales The name already gives away a bit of what task these veins are charged with You know that all animals need oxygen to survive The land vertebrates have lungs for this purp...

Page 31: ...uth Depending on what kind of nourishment the insect prefers its mouthparts are also adapted to their respective requirements A butterfly feeds from the nectar of blossoms which is sometimes buried deeply in the blossoms Consequently it needs a long proboscis with which it can suck its food from the hidden corners of a bloom To keep the proboscis from getting in the way during other activities the...

Page 32: ...ad to toe with yellow pollen On one of the leg segments it has a thick bristle coat the brush that it uses to brush the pollen out of its fur The brushed out pollen is stuck together with honey and kneaded in the pollen pincers You ve probably already seen how bees transport the pollen that has been kneaded into pollen packages Namely the bee also has a basket in which it transports the pollen Lon...

Page 33: ...oroplasts Like us fungi nourish themselves off of other organisms This is why many fungi are also scroungers parasites or even pathogens But they also take on one of the most important tasks on our planet They decompose dead organisms So one could say that fungi are an important part of the cycle of life In this way they also ensure that the stored up life energy does not go to waste For the fungi...

Page 34: ...ow fungi dif fer clearly from the compact structure of plants Fungal hyphae run through the entire forest floor but are invisible to us Only in some places and when it s warm and moist enough do fruiting bodies grow out of these fungal threads which we then refer to as actual mushrooms in our everyday language So what we see of forest mushrooms is actually only the tip of the iceberg so to speak A...

Page 35: ...hey open up and the spores are then released freely You can also see very similar structures under the microscope yourself for example in a button mushroom Top view of the cap cross section Point at which the lamella is attached to the stem The fungus known as pear rust is a plant disease and causes these rust brown spots Lamella with spores Friend and Enemy Many fungi are a true enemy of plants a...

Page 36: ...gae The algae converts energy from the sun into food for the fungus and the fungus makes it possible for the algae to live out of water in the first place The success of this living arrangement is proven by the tenacity with which lichens inhabit even the most unpleasant of living spaces including on walls and stones on tree trunks and even on bare rock in the high mountains where they are exposed...

Page 37: ...t possible to pull a full grown plant out of the Earth along with the zone in which the root hairs are located Consequently you are better off using the roots of seeds that have just sprouted You will need cress seeds they can be found in the garden center or supermarket an empty margarine tub you can also use a small bowl or a saucer cotton wool or tissues a slide and a cover slip the pipette and...

Page 38: ...the root hairs are so tender that the water is able to pass through them into the cells of the root But how does the water then travel to the other parts of the plant Transporting the water from cell to cell would not only be tedious but also much too slow Just as there are veins in humans to take care of transporting the blood and hence water there are specialized vascular ducts in plants too the...

Page 39: ...ong wind for example Nature also faces the same problems when it decides to build upward and it has found some incredible solutions Grass Blades Rigid Light Design The blade of grass on which the ant is sitting has to be both stable and flexible at the same time Sufficient flexibility is already ensured by the construction material alone Plant cells can be compressed and stretched to a limited ext...

Page 40: ... another look at the cross section as a whole you will notice that the blade achieves maximum stability with little effort and while saving as much material as possible It s any engineer s dream It can prove interesting to stain this particular specimen with a blue stain see page 16 Look at the specimen under the microscope you will notice that the various types of cells have absorbed the color to...

Page 41: ...old Whether the base of a tower or the roots of a plant extreme reliability is a must It s apparently most favorable to change the construction principle in comparison to the stem since the stabilization tissue of a root which also serves as a vascular duct is not wrapped around the rest of the root as a sheath but rather as a central strand in the middle of the root like a steel cable with a shea...

Page 42: ... a small portion of the surface that you want to study with the colorless nail polish Now you ll need to let it dry Depending on the air tem perature this will take 5 10 minutes Then stick a small strip of clear adhesive tape onto the painted surface and carefully pull the strip off again The dried nail polish separates from the surface Affix the adhesive tape with the impres sion on a slide and c...

Page 43: ...rkings of the leaf and preventing a lot of water from evaporating from the leaf Both tasks of the epidermis are visible in the structure of the cells If you look at the epidermis from above you will notice that its cells which are different from plant to plant often have bizarre shapes Little arms fit together like a puzzle Just like in a puzzle the interconnected nature of the individual cells br...

Page 44: ... upward from the root What do a bath sponge your lung and the leaf of a plant have in common Not much at first glance But the answer lies in the detail Air reaches one of your two lungs through the trachea But the lungs are not sim ply empty sacks In the lungs the bronchia branch out into extremely tiny vessels This is advantageous in that your lung increases its surface area many times over It s ...

Page 45: ...u re looking at is not the cross section but a top view of the top or underside of the leaf So here s another tip Cut very thin wedges You surely won t be able to see anything on the thick end but you will generally get a good cross section on the thin end Apart from that the rule is Practice makes perfect In leaf cross sections one finds many round or oval cell groups at the boundary between the ...

Page 46: ... aspect of forensic work is the identification of hairs The hairs of humans and animals can be distinguished under the microscope and often small details in the structure of the surface are all that allow the hairs of different animals to be differentiated from each other or sometimes it s the thickness of the hair Under the microscope animal hairs plant hairs plant fibers such as flax or linen an...

Page 47: ...why the cotton plant forms its 6 inch long fibers Plants have a wealth of strategies for distributing their descendants The more widely the fruits and seeds can be spread the higher the chance of populating a place that s not already overgrown The hairs of the cotton plant are seed hairs that serve as flight organs So it s the wind that ensures that the descendants of a cotton plant are scattered ...

Page 48: ...ed swallows in their swift flight on a warm summer evening Or the elegant sailing flight of large sea birds such as gulls or terns A bird s body structure has many peculiarities that make this enviable manner of locomotion possible The characteristic that you surely think of first and rightly so is the feathers A feather is an amazingly light and very often wonderfully colorful natural structure U...

Page 49: ...smallest indivisible particles The Greeks called these smallest particles atoms Of course Democritus and his colleagues were not able to prove their claim so there were others such as the famous philosopher Aristotle who vehemently rejected this theory However the results of the research of the 19th and 20th centuries support this theory and even demonstrated that the smallest particles are compos...

Page 50: ...bject at any one point more or fewer electrons are released from the object by the electron beam hitting it These electrons are then registered by a detector and translated into an image by a computer Black and white images are produced using this method which are then colored artificially on the computer Despite all advantages and possibilities that an SEM offers even this device has its limits A...

Page 51: ... Option 1 You can simply reproduce the page by hand It is okay if the templates do not all look exactly the same but they should all have the same fields for information Option 2 If you have access to a photocopier you can make copies of this one template page and glue it into your logbook Or if you prefer this photocopier method you can simply use a three ring binder as your logbook and store you...

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