Betzold A03 Mode D'emploi page 9

After use
When having finished working with the microscope, turn off the current. Use the button for coarse adjusting to move the
object stage downwards. The device should be protected by a dust cover, or disassembled and put back into the original
Styrofoam packing.
c) Exchanging the tungsten bulb of the microscope model A03
A tungsten bulb (220/230 Volt, 20 Watt) is required.
First pull out the power plug! Loosen the screws at the bottom of the microscope, and remove the base plate. Replace the
used bulb by a new one. Pay attention – the bulb should not be touched with your fingers, as this might shorten the operating
time. Replace the base plate.
Suggestions for the observation of specimen
Children should not experiment without adult supervision!
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 recrystallization 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 the microscope. Usually these objects are dyed, to make the cells more
visible. A current dye is iodine. You can also dip your tissue sample for some minutes into normal, diluted food colouring,
in order to dye it. Use a pair of tweezers to transport the dyed objects. Bear in mind that the colour will dye any objects
contacted. Therefore take care of clothing and furniture.
9