Bresser 88-54000 Instrucciones De Uso página 16

Experiment No. 3: Textile fibers
Objects and accessories:
1. threads from various fabrics (e.g.
cotton, linen, sheep's wool, silk,
rayon, etc.),
2. two needles.
Place the different threads on a table
and use the needles to fray them a
bit. Dampen the threads with a little
water. Set your microscope to the
lowest magnification and place it on
the threads, one at a time.
Compare: Cotton fibers come from
a plant, and look like a flat, twisted
ribbon under the microscope. The
fibers are thicker and rounder at the
edges than in the middle. Cotton
fibers are basically long, collapsed
tubes. Linen fibers also come from
a plant, and they are round and run
in one direction. The fibers shine like
silk and exhibit countless bulges on
the thread. Silk comes from an ani-
mal and is made up of solid fibers that
are small in diameter, in contrast to
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the hollow plant-based fibers. Each
fiber is smooth and even and looks
like a tiny glass tube. The fibers of
the sheep's wool also come from an
animal. The surface is made of over-
lapping sleeves that look broken and
wavy. If possible, compare sheep's
wool from different weaving mills. In
doing so, take a look at the different
appearance of the fibers. Experts
can determine which country the
wool came from by doing this. Rayon
is a synthetic material that is pro-
duced by a long chemical process.
All the fibers have solid, dark lines on
the smooth, shiny surface. After dry-
ing, the fibers curl into the same posi-
tion. Observe the differences and the
similarities.
Experiment No. 4: Table Salt
Object: normal table salt.
Place a sheet of black paper on a
desk. Sprinkle a few grains of salt on
the paper and place the microscope
on top of them. Look at the salt crys-
tals using the lowest magnification of
your microscope.
Observe: The crystals look like tiny
dice and all have the same shape.
Experiment No. 5:
Leaves and Needles
Object: 3-4 different leaves or nee-
dles from deciduous trees or fir
trees.
When you go for a walk in the forest
with your parents, you can collect dif-
ferent types of leaves and needles.
At home, place them next to each
other on a white sheet of paper. Place
your microscope on top of them and
look at the different leaves and nee-
dles with the lowest magnification.
Observe: The leaves of the decidu-
ous trees have different but more or
less regular sections that are separat-
ed by lines. These are called "cells."
Most often, the underside of the leaf
looks different than the top, and the