Bresser National Geographic 91-19501 Instrucciones De Uso página 15

with a dish. Place the glass container in a bright location, but don't put it in direct sunlight. Since you have
a hatchery, you cal also add the salt solution along with a few eggs to each of the four compartments of the
tank. The temperature should be around 25º. At this temperature, the shrimps will hatch in about 2-3 days.
If the water in the glass evaporates, add some water from the second container.
The Brine Shrimp under the Microscope
The animal that hatches from the egg is known by the name "nauplius larva." With the help of a pipette,
you can place a few of these larvae on a glass slide and observe them. The larvae will move around in
the salt water by using their hair-like appendages. Take a few larvae from the container each day and
observe them under the microscope. In case you've hatched the larvae in a hatchery, simply take off
the cover of the tank and place the tank on the stage. Depending on the room temperature, the larvae
will be mature in 6-10 weeks. Soon, you will have had raised a whole generation of brine shrimp, which
will constantly grow in numbers.
Feeding your Brine Shrimp
In order to keep the brine shrimp alive, they must be fed from time to time, of course. This must be done
carefully, since overfeeding can make the water become foul and poison our shrimp population. The
feeding is done with dry yeast in powdered form. A little bit of this yeast every second day is enough. If
the water in the compartments of the hatchery or your container turns dark, that is a sign that it is gone
bad. Take the shrimp out of the water right away and place them in a fresh salt solution.
Warning!
The shrimp eggs and the shrimp are not meant to be eaten!
7.2. Textile fi bres
Objects and accessories:
1. Threads of different textiles: Cotton, linen, wool, silk, Celanese, nylon and any others you can fi nd.
2. Two needles:
Put each thread on a glass slide and fray each with the help of the two needles. Put a drop of water
over each thread with the pipette and cover each with a cover glass. Adjust the microscope to a low
magnifi cation. Cotton fi bres are of plant origin and look, under the microscope, like a fl at, twisted band.
The fi bres are thicker and rounder at the edges than in the centre. Cotton fi bres consist primarily of
long, collapsed tubes. Linen fi bres are also of plant origin; they are round and run in straight lines.
The fi bres shine like silk and exhibit numerous swellings along the shaft of the fi bre. Silk is of animal
origin and consists of solid fi bres of smaller diameter than the hollow vegetable fi bres. Each silk fi bre
is smooth and even and has the appearance of a small glass rod. Wool fi bres are also of animal origin;
the surface consists of overlapping scales, which appear broken and wavy. If possible, compare wool
fi bres from different weaving mills, and note the differences in the appearance of the fi bres. Experts
can determine the country of origin of wool based on its appearance under a microscope. Celanese
is artifi cially manufactured by a long chemical process. All Celanese fi bres show hard, dark lines on a
smooth, shining surface. The fi bres crinkle in the same way after drying. Observe the similarities and
differences between the different fi bres.
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