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c) Work with reflected light: Use of the above light source
(for solid objects and for the observation of surface structures)
Switch the above light on to illuminate the stage. Just as with the work with the transmitted light, always begin with the 4x objective
and increase the magnification accordingly.
Attention! For the observation of solid objects only the 4x and the 10x objectives are suitable. The 40x magnification is
unsuitable for the use with reflected light due to the necessary distance needed for the focus. For contrast reasons it
might be necessary to place some specimen on a card or a small piece of paper before placing them on the stage. As you
are using the light from above, it is not necessary that the opening in the stage stays open. Furthermore, you avoid your
specimen falling through the hole.
This kind of observation makes it possible to magnify countless objects from daily life: e.g. small stones, leaves, insects,
flowers, coins, stamps etc.
Hints for working with reflected light:
You will notice (for example with a little insect) that you can adjust the focus on different levels. This shows that it is not
possible to focus the whole object with only one adjustment as it is possible with flat objects like stamps, where the whole
object is on only one level.
Suggestions for the observation of specimen
Children are not allowed to do experiments without being supervised by an adult!
1. Place some grains of salt or sugar on the object holder.
2. Dissolve a teaspoon of salt/sugar in warm water in a test tube. Then use the pipette to place some drops on an object
holder. Let them dry and observe the recrystallisation of the salt/sugar.
3. Shake some pollen of a blossom onto an empty object holder.
4. It is interesting to observe parts of feathers or any hair, that of domestic animals included. Try to compare the hair of
different animals. You can fix the hair with a small piece of sticky tape onto the object holder.
5. Observe the fibres of different types of paper, or compare the print of a newspaper with that of a type writer or a laser
printer.
6. Look at the colours in comics, or at strings and fibres of different materials.
7. Compare natural fibres like cotton wool or wool to synthetic ones like polyester.
8. Water out of a pond contains living organisms. Put a drop of it onto the object holder with the dip to observe them.
9. Very small insects can be looked at with little magnification.
10. Or try to look at parts of bigger beetles like legs or wings. Doing this, the needle is useful for the positioning. Always take
insects with tweezers and wash your hands carefully after handling them.
11. Watch the mould on old bread or other food. Or create your own mould culture by putting a little piece of bread into a
petri dish for some days. A little moistness accelerates the moulding process. (Here too, wash your hands carefully after
work.)
12. Many objects seem to be transparent under a microscope. Usually, these objects are coloured to better recognize the
cells. Iodine is a popular dye. You can also put your specimen in food colour for some minutes in order to dye them.
Use the tweezers to handle the coloured objects. Let the coloured objects dry before putting them under the
microscope. Keep in mind that the colour dyes all objects it gets in touch with, so watch out for your clothes and
furniture.
Suggestions for self-made specimen
Always start with clean object holders and cover glasses. In order to avoid fingerprints, always take the object holders
exclusively by their sides. Place the cover glass cautiously using the tweezers.
Special attention and supervision by adults is necessary when the scalpel is used to cut objects. Whenever you do not
use the scalpel, wrap it up and store it in a secure place.
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