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