Chapter 5 Observation of Natural Phenomena

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Chapter 5 Observation of
Natural Phenomena
A. Scientific Method
B. Motion
C. Microscope
D. Work Safety
Chapter 5 Observation of Natural Phenomena/133
Concept Map
Study of Natural
Phenomena
uses
Scientific Methods
include
Identify phenomena
a problem
Scientific Knowlege
Scientific attitudes
consists of
such as
Scientific facts
Curious
Make a hypothesis
Concepts
Objective
Do an experiment
Principles
Open-minded
Analyze data
Teory
Perseverance
Law
Scientific process
Draw a conclusion
Develop theories & laws
134/Chapter 5 Observation of Natural Phenomena
Observation of Natural
Phenomena
Science is a systematic study of natural phenomena. Scientists study natural phenomena by conducting research very
carefully. The results of their research give us advantages in our
lives. They can explain what happens and why it happens, estimate what is happening at present and what is going to happen
to our nature in the future. Their discoveries and inventions are
very useful for people welfare. Some of their inventions are computers, hybrid cornseeds,
and so on. You might wonder how scientists work. Do they wear white robes and work
for hours at the laboratory? Of course not. Just like all of us when we think of something
new, they start by asking questions.
In this chapter you will learn the excitement of phenomena that occur in nature
and how to study them. Sound, rain drops, lightning, motions,
microorganisms, plant growth, fragrance of flowers and smelly
waste, and pollution are among the natural phenomena.
Scientists study the phenomena by asking questions, making
hypotheses, and doing experiments. They may also use a
thermometer, a microscope, a hygrometer, a scale or other
devices. Scientists also develop such attitudes, i. e. curious,
honest, perseverance, open-mind, and tolerance. In order to
be a scientist you have to learn scientific methods. You may
Source: Author
practice using a scientific devices, equipment, and skills.
Do the following activity to help you understand the initial
steps of scientific research:
1. Cut a filter paper with the size of 3x12 cm.
2. Draw a line 2 cm from the paper’s corner with black ink.
3. Take a beaker glass or a plastic glass, fill it with water about
2 cm high.
4. Soak the paper in the water, with the line position above the
water surface.
Predict what will happen to the line. If your prediction is
different from the reality, will you change your prediction
according to the observation result? Why?
Figure 5.1
Position of filter
paper in the beaker
glass
Chapter 5 Observation of Natural Phenomena/135
A
Science Terms
• qualitative observation
• quantitative observation
• hypothesis
• experiment
• fact
• opinion
• scientific attitude
Scientific Method
The exploration that you just did is similar to what
a scientist usually does. A scientist works systematically,
using a scientific method and scientific process skills that
are commonly used to do a scientific investigation. These
skills are important for us to collect facts and to relate the
facts to make an interpretation or a conclusion. We need
to learn these skills not only to get more knowledge, but
also to apply them in our everyday life.
Figure 5.2
Scientific method in action
136/Chapter 5 Observation of Natural Phenomena
Source : Encarta encyclopedia
Have you ever thought that a big tree grows from
a small seed? A banyan (or beringin) tree can grow meters
tall with a mass of tons. Mass of a tree is a measurement
that is used by scientists to measure the amount of matters in a tree or other scientific objects. Measurements
like mass, length, width, and square can be indicated
by numbers. Yet, there are some other characteristics of
scientific objects that cannot be indicated with measurement, for example, taste, and smell. A rose has fragrant,
and a ripe mango tastes sweet.
What will happen if a piece of wood is placed in
a furnace? After a few hours, nothing remains but a little
ash. Where has the length, diameter, smell, and mass of
the wood gone? The wood is originated from a small seed
that grew fast and weighed more. Think of the following
question below.
Source: Author
Figure 5.3
The burning wood. After
several minutes ash
remains. Where has the
wood gone?
Observe Figure 5.4. Where
does the plant’s weight
come from? Write down
a possible explanation
to answer the question
in your Science Journal.
How would you test your
explanation?
Source: Author
Figure 5.4
A seed grows to a seedling, then to a big tree.
Where does the tree’s weight come from?
Chapter 5 Observation of Natural Phenomena/137
Observing the nature of plant organs
Plant organs consist of roots, trunks, leaves, flowers, and
seeds. Each part has particular mass, length, color, and
smell. Think of the characteristics that you can observe
without looking at the parts.
What You Need :
You may touch or smell to get qualitative
data
A pot of tomato, eggplant (=terung), or
chilli plant (choose one)
Black blindfold
Ruler
Scale
Note: the plant can be changed as long as
it is horticultured and not poisonous
What to Do :
1. Work cooperatively in a team.
2. Ask your team members to observe
the object. A member of the group will
take notes.
3. Have another member blindfolded.
4. Place the pot in front of him/her.
Ask him/her to observe the plant by
touching and smelling it.
Source: Author
5. Qualitative observation. Ask him/
her to mention the characteristics of
the plant organs, then ask him/her to
mention the name of the organs (root,
trunk, leaf, flower, or seed?)
6. Data collection. Note the observation
result in the following table. The
data you obtain are in descriptions of
characteristics, not numbers. This is
called qualitative data.
138/Chapter 5 Observation of Natural Phenomena
Sample data
Name of organs
Characteristics
Leaves
Oval-shaped,
thin, wide,
jagged-edge,
hairy surface,
and smelly
7. Compare the result of your observation
with other groups’ results. Are they the
same or different? If they are different,
could you explain why?
8. Quantitative Observation
Now open your eyes and measure the plant
organs with measuring tools. Measure the
mass of the whole plant after the soil is
removed. Take several leaves, measure the
length and the width. Measure the trunk’s
length and diameter. Measure the mass of
the fruit, if any. Write down the data in the
table below.
Name of
organs
Leaf 1
Leaf 2
Fruit 1
Fruit 2
etc.
Length Width
(cm)
(cm)
Mass
(gr)
Conclusion and Application
1. Write of the characteristics of the
plant organs that you observed.
2. Write of the measurement of the
plant organs.
3. Application. What is the mass of the
whole plant? Can you explain where
the mass comes from, regarding the
small size of the seeds?
Follow up :
Explain what you have learned
about:
1. Qualitative observation
2. Quantitative observation
Chapter 5 Observation of Natural Phenomena/139
How do scientists wok?
Here is an example of scientists’ activities.
Scientists have been studying about changes on plant
growth for hundreds of years. They have come to
a conclusion that plants get food from the ground by
absorbing it through the roots. It was Jan Baptista van
Helmont who proposed this argument. Helmont’s
argument has changed the way people think of plant
growth for 300 years.
A sc i entist is always curious to know
everything that happens around him/her. She/he
asks questions, and will try to find the answers to the
questions. Helmont proposed the following question:
Do plants really absorb food from the ground as people have
assumed so far? He wanted to test the truth by designing
an experiment.
Does the plant’s mass come from materials
absorbed from the soil during its growth? Helmont
proposed an argument. If a plant took food from
the soil, then the soil around it would be reduced
or get lighter. Helmont designed an experiment to
test his hypothesis. His finding has changed the way
scientists think about a plant’s growth.
A scientist has to consider some factors that
should be controlled in her/his experiment. This can
be done by identifying or determining what causes the
changes in the experiment. To investigate whether the
plant absorbs soil around it as its food, Helmont decided
to measure weight of the soil.
140/Chapter 5 Observation of Natural Phenomena
Figure 5.5
Jan Batista van
Helmont did a scientific
investigation of the
addition of plant mass.
Does a Scientist Learn from Others’ Work?
Mass is indicated with
1 pound = 0.4536 kg.
1 ounce = 0.02835 kg.
Pound and ounce are
measurement units for mass
that are commonly used in
England. Change the result
of measurement done by
Helmont into International
Standard.
Helmont had planted a 5-pound willow tree
(Figure 5.5) in a big box of 200-pound soil. He then
observed the soil for five years. During the five-year
period, his measurement indicated that the plant’s
mass increased from 5 pounds to 169 pounds, while
the soil’s mass only decreased as much as 2 ounces.
This evidence shows that the increase in the plant’s
mass did not completely come from the soil, but from
something else.
The experiment answered one question, but
brought up another question. Where does the plant
mass come from?
Helmont assumed that water was the main
requirement for a plant to grow. Now we know
it is true. A plant uses water to increase its mass.
Besides, all green plants need sunlight. They carry
out photosynthesis to react water with carbon
dioxide with the help of sunlight to produce sugar.
The sugar is used to grow trunks, roots, seeds, and all
parts of the plant. During this growing process a plant
utilizes absorbed minerals that are from the soil.
Figure 5.6
The willow tree planted by Jan
Batista van Helmont.
Chapter 5 Observation of Natural Phenomena/141
How do scientists raise questions ?
Roy Renkin, a biologist who worked for Yellowstone National Park in
Wyoming, studied the process of plant growth. Based on Helmont’s research, Renkin
learned that the observed plant did not absorb much soil to increase its mass. This aroused
new questions to Renkin. What makes plants in the park grow? If they die, can they grow
again?
In August 1988, the forest in Yellowstone National Park was burned. The wind blew
at the speed of 112 kilometers/hour, bringing the fire as high as 110 meters. A million
hectares of forest were destroyed.
The forest fire was a tragedy, but for Roy Renkin, this brought a big question. How
does a forest grow?
Figure 5.7
A burned forest slowly turns green again. This is called a succession.
Many scientists believed that forest fire had destroyed roots and nutrition in the
soil. The Yellowstone forest fire proved that it was not true.
Some trees even uses forest fire to help their regeneration process. Some pine
strobilus fell with open scales, with seeds ready to come out. After the fire, Renkin and other scientists found more than one million of pine seeds in the 1-hectare
forest area. Renkin also found that the ash resulting from fire actually increased soil nutrition within 1 or 2 years time. Five years later, the forest was already covered with new
trees.
Figure 5.8
A pine tree, with a strobilus.
142/Chapter 5 Observation of Natural Phenomena
Becoming a scientist
To become a scientist you must
begin with curiosity. A scientist is
curious about her/his surroundings and
ask questions about them. How can a coco
tree grow very tall? How can it gain weight?
How does fertilizer increase the growth
of the plant? Basically, you can observe
everything that interests you. You can ask
questions: what, why, where, when, and
how that happens.
Thinking like a scientist means
that you try to find the answers to your
questions. Sometimes the answers do
not seem to make sense to other people.
Helmont did his experiment because
he did not accept the earlier scientists’
opinion.
Choose a tree, and determine what
you can observe (Figure 5.9). See whether
the result of your observation gives you a
different hypothesis.
Now do the following activity to help
you learn to become a scientist.
Figure 5.9
Do you have questions about the above
coconut tree? How would you answer your
questions?
5.1
Observing and Asking
Questions
Observe two pots which contain
plants. Pot A has a plant with
fresh leaves, while the plant in
pot B looks tarnished. Note the
result of your observation. Can
you draw a conclusion about
the condition of the two plants?
Formulate a question, and give it
to your class.
Chapter 5 Observation of Natural Phenomena/143
Investigating where the Mass of a Plant Comes
From
Problem
5.2
Where does the mass of a plant come from?
Think of a hypothesis to answer the question.
A hypothesis is a statement that answers a question. You have to
test the statement by conducting an experiment.
What You Need :
• 20 seeds of beans
• A scale
• Water
• 4 Paper/plastic bowls (used as pots)
• Garden soil
•A ruler
• Science Journal
What to Do :
1. Fill the pots with soil. Measure the
mass of the soil and make sure each
pot is filled with soil of the same
mass. Take notes of the mass and the
experiment date in your journal.
2. Measure the mass of each seed. Take
notes. Plant 5 seeds in each pot.
3. Place the pots in a lighted area.
Water them with the same amount
of water everyday.
4. Observation. After one month,
measure the height of the plants
with a ruler and take notes. Slowly,
pull the plants out of the pots.
Remove the soil from the plants.
Measure the mass of the plant, and
take notes. Next, measure the mass
of the soil and take notes.
5. Data Interpretation. Compare the
mass of the plants and the mass of
the soil at present with the previous
month weight.
The following table shows sample
data.
Average
January
Height of plant
Mass of plant
Mass of soil
3 cm
2g
225 g
February
25.4 cm
68 g
223 g
Conclusion and Application
1. Drawing a conclusion. How many 2. Do you think that the plant gains weight
from the soil? or from the water? Explain
grams are gained by the plant in a
by using the data.
month?
144/Chapter 5 Observation of Natural Phenomena
Questioning
To be a scientist means that you ask questions about
whatever happens in your surrounding. When you discuss
the origin of a tall tree, you can ask about where the weight of
the tree comes from. When you observe the root and tip of a
grown seed, you can ask about how the root and tip emerge.
Look at Figure 5.10 that shows Mimosa pudica. What questions
do you have in mind? Then ask yourself how to answer your
question.
(a)
Designing an Experiment
At the beginning of an experiment, you should
start with a hypothesis. Hypothesis is an idea, thought,
or assumption about what will happen if you test a
problem. From this assumption, then you can design an
experiment.
You can measure all materials you need, and start
your observation. You have to take notes and organize
(b)
information to get better understanding of what you are
observing. You will share the result of your observation Figure 5.10
with your class. Just like a scientist, you should also look at Possible questions about
Mimosa pudica: How long do
your friends’ data.
Using Research Results to Answer
Questions
leaves of Mimosa pudica close
due to a touch? What makes
them close?
To be a scientist means that you should make a keen
observation. You should also record the data, analyze the
data of your observation, and draw a conclusion.
After measuring, you know now that the increasing
mass of the tree and the mass of the soil. When you analyze
that the mass of the soil is almost the same, you can make
a conclusion that the mass of the plant does not come from
the soil. From this, you know whether your hypothesis is
right or wrong.
A scientist always shares his/her research result with
other people. You can share data with other groups. You
can make a table to help you understand a piece of information better. You can also take notes of your explanation to
the questions in your Science Journal.
Source : google.co.id
Figure 5.11
Scientists always share their
research result with other
people
Chapter 5 Observation of Natural Phenomena/145
Sharing research results helps a scientist
m e a s u r e t h e st r e n g t h o f t h e h y p o t h e s i s. Y o u c a n
compare their research results with other scientists that conduct
the same research. A scientist can even repeat a research previously conducted by another scientist.
You can learn from your classmate’s experiment
just as Renkin learned from Helmont’s experiment. The
experiment result indicates that the increase of plant mass does
not come from the soil. The result does not indicate where the
mass comes from.
How can you improve Helmont’s experiment? What
questions might lead you to another new experiment? For
example, you can question whether the amount of water can
increase the mass of the plant. How would you answer the
question?
All the steps you have learned are known as a
scientific method. This method guides you to become a true
scientist. Knowing how to find the answer is just as
important as finding the answer to a problem.
146/Chapter 5 Observation of Natural Phenomena
Scientific Attitudes
Curious
• Wanting to know a
phenomenon
• Gathering evidences
• Getting information
from many sources
Honest
• Reporting objectively
• Acknowledging the
work of others
Open-minded
Let’s Read
Read the biography
of great scientists
who have contributed
a lot to humanity,
such as: Anton van
Leeuwenhoek, Pasteur,
Marie Curie, Isaac
Newton, Archimedes,
Einstein, Galileo,
Lavoisier, Mendelejef,
Rutherford, Bohr,
Pauling, Copernicus,
Harvey, Mendel,
Fleming, etc. We are
indebted to them for the
development of science.
• Willing to accept new
ideas but at the same
time not believing that
all you read is true or
correct
Tolerant
• Willing to change ideas
• B e i n g f a r f r o m
arrogance
Optimistic
• Nothing is impossible
for scientist
Chapter 5 Observation of Natural Phenomena/147
The above scientific attitudes show us the direction that someone is supposed to
take if he/she wants to develop scientific attitudes in their lives. No one is born a scientist.
Those who possess these attitudes have worked hard for that.
Reading biography of scientists may also help us develop scientific attitudes. We
will learn about their lives, their achievements, as well as their weaknesses and limitations.
Learning about them will make us understand and respect them, and imitate their good
sides, because scientists are human beings after all.
1. What strategies do you use to test your questions? Can you give three examples of
good research questions?
2. Can you make possible answers to your question? What would you name these
possible answers?
3. A scientist does not work alone. She/he always uses previous studies conducted by
other scientists as references. Why?
4. What is the basis of a scientific conclusion?
5. What is an experiment? Can you make a design of an experiment?
Skill Building
Conducting an Observation
Observe a plant or an animal in your surrounding. Note the result of your
observation. Write the result of your qualitative observation and the quantitative one
separately. Report it to your teacher.
148/Chapter 5 Observation of Natural Phenomena
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