SCIENTIFIC
PROCESS IN BIOLOGY.
Biology, just
like other science subjects, involves carrying out experiments. When studying living
things simple observation can be made by using our own senses i.e. sight, smell,
touch, taste and hearing. The senses can be detected by our sense organs i.e. eye for
sight, nose for smell, skin for touch, tongue for taste and ear for hearing.
MEASUREMENTS
OF MASS, LENGTH, TEMPERATURE AND PULSE RATE
Take measurements
of mass, length, temperature and pulse rate
Measurements:
When carrying out biological investigation measurements like mass, time, temperature, and length are unavoidable.
INSTRUMENTS
USED FOR VARIOUS MEASUREMENTS:
Beam balance – for
measuring mass
Thermometer – for
measuring temperature
Clock/stopwatch –
for measuring time
Ruler – for
measuring length
Pulse rate can be
measured by using a stethoscope or by pressing the fingers firmly on the skin.
The study of biology like any the science subject
involves scientific processes. The scientific
processes involved in the study of biology include observation, measurement and
experimentation. Through these processes the study of biology becomes possible.
OBSERVATION
Through observation we can learn many scientific phenomena. Observation is made
by using our own
sense organs. There are five sense organs in the human body which are eyes, ears, the nose,
the tongue, and the skin. Each of these organs is specific to a certain type of
observation.
The following are
sense organs and their associated functions in observation.
Eyes
By using your
eyes you can observe differences in colors of the two things given and then
tell their differences. We use our eyes as a sense organ
for vision. By using our eyes we are able to see and differentiate sizes, colours and shapes of various organisms and hence we
can learn about them.
Ears
How can you distinguish between the sound produced by a singing bird and
a roaring lion? Sometimes
you can just use your ears to study various biological concepts. For example
many organisms produce different sounds which we can use to identify them. Therefore,
it is easy for a biologist to know an organism just by hearing the sound without
even seeing it.
Nose
Sometimes in the scientific study we need to smell in order to identify and
distinguish between
various things. For example, how can you distinguish the smell of a ripe banana
from that of a ripe pineapple? As a scientist you must be able to use your nose as
a sense organ effectively and successfully. BUT avoid smelling anything in the laboratory
without the permission from your teacher or laboratory technician.
Tongue
We use tongue to taste various things. By use of tongue we can
differentiate various tastes
and be able to discover the type of the taste concerned. For example, one can differentiate
salt from sugar solutions by just tasting using the tongue. BUT avoid tasting
anything in the laboratory unless you are told do so by the teacher or
laboratory technician.
Skin
We can use the skin as a sense organ to detect heat, temperature, pressure and
even pain.
For example, during a hot day you feel hot while during cold days you feel
cold. Even
if you close your eyes, and someone rubs your skin using a block of ice, you
can simply
tell it by just feeling the coldness it imparts to the surface of your skin.
MEASUREMENT
Though we can use
our sense organs to make observations, the observations alone are not so reliable.
Every sense organ has its weakness. Since science lies upon measurable
quantities there is a need of measurement. Scientists have been able to design ways to
take measurements of various things. Some of the quantities which can successfully be
measured include mass, temperature, length and pulse rate.
Measurement
of length
We can use eyes
to observe the length of various objects. However, our eyes can just tell which object
is longer than the other but cannot tell us what the exact length of each object is.
Tape measure is one of the common instruments that are used for measuring length
in our everyday life. Tape measure, an
instrument for measuring length
Measurement
of mass
A scientist
or biologist must have a standard way of measuring mass of a substance. Sense organs
cannot give us the true value of mass of a substance. This can be done by using beam
balance which is a special instrument for measuring mass of a substance.
Measurement
of temperature
We can take the
measurement of temperature of a substance just by using our sense organs. For example, by touching something you can tell whether a particular thing is hot or cold.
However, you cannot tell exact temperature of an object. Therefore, to be
able to know the exact temperature you need to use an instrument specially designed for measuring the temperature. This is instrument is the thermometer. Using thermometers we are able to know
the exact temperature of an object.
Measurement
of pulse rate
Pulse rate refers
to average beating of your heart. You can find how fast your heart is beating, that is
your heart rate, by feeling your pulse.
How to
measure your pulse rate
Sit down
comfortably on a chair with the palm of your hand facing upwards. Gently place the index
and middle fingers of your other hand on your wrist.Can you feel your pulse as a repeated throb? If necessary
change the position of your finger until you can feel your pulse rate well. Count the number
of heart beats in one minute. Repeat step 3
four times. Write down the
number of beats per minute.
Work out the
average. This is what is called average heart rate per minute. It tells you how fast your
heat is beating.Measuring the
pulse rate
EXPERIMENTATION
Biology as a
science subject involves practical work. In every area of biology,
experimentation
is necessary.
SCIENTIFIC PROCEDURES FOR SCIENTIFIC INVESTIGATION.
There are several procedures to be followed in conducting any scientific investigation. These procedures include the following:
Identification of a problem (problem statement)
In our day to day
life we often come across questions or phenomena which require explanations.
Such questions or phenomena are of interest to a biologist who will seek to provide
answers to them.
The phenomena
could be for example; it was observed that the harvest of tomatoes in Juma’s garden was
low despite frequent irrigation, correct planting techniques, timely planting and adequate sunlight. So, what was the problem with Juma’s garden?
This is the
problem to be investigated by the biologist in order to come up with an answer.
Hypothesis formulation
Hypothesis is a
tentative explanation for the observation made. Using your example of low yield in the
tomato garden, the possible hypothesis could be poor yield could have been caused by
low soil fertility and therefore application of the fertilizer could increase harvest of the
tomatoes in the garden. This hypothesis must therefore be tested by experimentation
if it has to be a scientifically acceptable explanation.
Select two plots, A and B, from the same garden and subject both of them to the same conditions as before. In plot B apply fertilizers while in plot A don’t put any fertilizers (plot A will be your control plot).
Interpretation
of data
Once a researcher has
collected data, he should try to explain the meaning of data in relation to the purpose of the experiment. In the tomato garden experiment, the harvest in plot A was
little compared to the harvest in plot B.
In these plots,
all the conditions were the same except that in plot A no fertilizers were applied while in
plot B fertilizers were applied. Therefore, high harvest in plot B was a result of
applying fertilizers. If this experimentation is correct, then the same results should be
obtained if the experiment is repeated under the same conditions.
Conclusion
At the end of
investigation, a researcher must draw conclusion. This conclusion is based on the
collected data. The conclusion is either confirmation or rejection of the hypothesis under
investigation.
In the tomato
garden experiment, the results have shown that application of fertilizers has increased the
harvest of tomatoes. Therefore, low harvest of tomatoes was caused by poor soil
fertility.
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