Bresser BIOLUX ADVANCE 20X-400X Instrucciones De Uso página 19

7.2. Textile fibres
Objects and accessories:
1. Threads of different textiles: Cotton, line,
wool, silk, Celanese, nylon etc..
2. Two needles
Each thread is put on a glass slide and
frayed with the help of the two needles. The
threads are dampened and covered with
a cover glass. The microscope is adjusted
to a low magnification. Cotton staples are
of vegetable origin and look under the
microscope like a flat, turned volume. The
fibres are thicker and rounder at the edges
than in the centre. Cotton staples consist
primary of long, collapsed tubes. Linen fibres
are also vegetable origin; they are round and
run in straight lines direction. The fibres shine
like silk and exhibit countless swellings at the
fibre pipe. Silk is animal origin and consists
of solid fibres of smaller diameter contrary
to the hollow vegetable fibres. Each fibre
is smooth and even moderate and has the
appearance of a small glass rod. Wool fibres
are also animal origin; the surface consists of
overlapping cases, which appear broken and
wavy. If it is possible, compare wool fibres of
different weaving mills. Consider thereby the
different appearance of the fibres. Experts
can determine from it the country of origin
of wool. Celanese is like the name says,
artificially manufactured by a long chemical
process. All fibres show hard, dark lines on
the smooth, shining surface. The fibres ripple
themselves/crinkle after drying in the same
condition. Observe the thing in common and
differences.
7.3. Brine shrimps
Accessories:
1. Brine shrimp eggs (Fig 2, 25d)
2. Sea salt (Fig 2, 25c)
3. Hatchery (Fig 2, 23)
4. Yeast (Fig 2, 25a)
CAREFUL!
Eggs and brine shrimps
are not fit
consumption.
9.3.1 The lifecycle of a brine shrimp
The brine shrimp or artemia salina to scientists
has an unusual and interesting lifecycle. The
female's eggs are hatched without any male
shrimp having to fertilise them. The resultant
baby shrimps are all female. Under unusual
circumstances such as when a swamp is
drained the eggs may produce male shrimps.
These males fertilise the female's eggs,
resulting in a specific type of eggs. These
are called winter eggs and have a thick shell
as protection. They're pretty rugged and can
survive the swamp or lake drying out causing
the death of the entire shrimp population for
up to a decade in a form of hibernation. The
eggs hatch once again as soon as the correct
ambient conditions have been obtained. The
eggs supplied (Fig 2, 25d) are of this type.
7.3.2. Hatching of the brine shrimp
To hatch the shrimp it is essential to first
have a saline solution suited to the shrimp's
needs. Fill half a litre of rain- or fresh-water in
a container. Let it stand for about thirty hours.
As water evaporates over time it's a good idea
to have a second container of such water left
standing for thirty-six hours. Once stood for
this length of time pour half of the sea salt
supplied into one of the containers (Fig 2,
for human
25c) and stir until it has dissolved. Then pour
some of it into the hatchery (Fig 2, 23). Add a
few eggs and close the lid. Put it somewhere
with plenty of light but not in the direct sun.
The temperature should be approximately
25° C. The shrimps will hatch in two or three
days at this temperature. Should any water
evaporate during this time replace it from the
second container.
7.3.3. The brine shrimp under
the microscope
What comes out of the egg is known as a
nauplius larva. Use the pipette (Fig 2, 22a) to
put some of them on a slide for examination.
They will move in the solution using their
hair like limbs. Remove a few daily from
the container for examination under the
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