Page 17 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

A hand lens
Biology laboratory is a special room This is mainly used to magnify
or building designed for carrying out specimens that are under observation. A
biological experiments. A laboratory hand lens enables a scientist to magnify
should have good qualities and facilities small organisms or their parts in order
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which include large door which open to observe them clearly. An example of
outwards, adequate space for carrying a hand lens is shown in Figure 2.1.
out experiments, proper lighting, good
ventilation, a source of water, a source
of heating, and adequate space for

storing apparati, chemicals, models,
and specimens.

A wide variety of apparati (singular is Figure 2.1: Hand lens
apparatus) and equipment are needed in
order to conduct Biology practical. The Scientists usually make drawings of
objects which they observe using a
following are some common Biology hand lens. The size of drawing that
laboratory apparati, equipment and they make is usually larger or smaller
resources: than the actual object.

Magnification is calculated as follows:
Size of drawing
Magnification of a drawing =
Size of an actual object
Size of actualobject

For example, if the length of the drawing is 8 cm and the actual length of the
object is 2 cm, then:

8
Magnification of a drawing
Magnification of the drawing = = 4
2
Sweep nets

A sweep net is used for catching small
flying organisms, such as butterflies,
grasshoppers and other small animals.
An example of a sweep net is shown in
Figure 2.2.
Figure 2.2: Sweep net

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