Test Review Unit 0_1 Scientific knowlege

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1 Test Review Unit 0_1 Scientific knowlege THE SCIENTIFIC METHOD The scientific method is a process used by scientists to study the world around them and to obtain objective knowledge about it. WHAT ARE THE 6 STEPS OF THE SCIENTIFIC METHOD? 1. Identify the Problem 2. Form a Hypothesis 3. Design an Experiment 4. Perform an Experiment 5. Analyze the Data 6. Communicate the Results 1. IDENTIFY THE PROBLEM The scientific method starts with identifying a problem and forming a question that can be tested. A scientific question can be answered by making observations with your five senses and gathering evidence. The question you ask needs to be something you can measure, so you can compare results you are interested in. For example, How does fertilizer affect plant growth? would be a testable scientific question. It s important to do background research to find out what s already written about your question before starting your experiment. 2. FORM A HYPOTHESIS The second step in the scientific method is to form a hypothesis. A hypothesis is a possible explanation for a set of observations or an answer to a scientific question. A hypothesis must be testable and measurable. This means that researchers must be able to carry out investigations and gather evidence that will either support or disprove the hypothesis. Many trials will be needed before a hypothesis can be accepted as true. A hypothesis may be written as an If then statement. For example, If I give my plants fertilizer in the spring, then they will produce more flowers, is a simple hypothesis about how plants grow. In this example, you can measure the number of flowers. 3. DESIGN AN EXPERIMENT The next step in the scientific method is to test the hypothesis by designing an experiment. This includes creating a list of materials and a procedure a stepby-step explanation of how to conduct the experiment. Scientists must be careful in how they design an experiment to make sure that it tests exactly what the hypothesis states. A proper experiment compares two or more things but changes only one variable factors that change in an experiment. This type of experiment is called a controlled experiment. For example, when testing the affects of fertilizer on plants, you would test an experimental group (with

2 fertilizer) and a control group (without fertilizer). Then you would compare the results of the groups. 4. PERFORM AN EXPERIMENT Keeping detailed, accurate records is an important part of the scientific method. Before you begin your experiment, create a table in which to record your data. Data are the facts, figures, and other evidence gathered through observations. A data table provides you with an organized way to collect and record your observations. For example, your data table should list the independent variable (amount of fertilizer) in the first column and the dependent variable (number of flowers) in the second column. Then you can use your table to create a graph. Graphs help you understand and use that data. Graphs make it easy to identify trends and make predictions. The x-axis of your graph represents the independent variable, while the y-axis of your graph represents the dependent variable. 5. ANALYZE THE DATA The next step in the scientific method is to analyze the data. Data analysis is the process of interpreting the meaning of the data we have collected, organized, and displayed in the form of a table or graph. The process involves looking for patterns similarities, differences, trends, and other relationships and thinking about what these patterns might mean. The scientist then summarizes their findings and relates them to their hypothesis. For example, in your analysis of your plant experiment, you would refer to your table/graph to describe any relationships you observed between the plants with and without fertilizer. 6. COMMUNICATE THE RESULTS The last step of the scientific method is to communicate the results. After you gathered and analyzed your data, you draw a conclusion about your hypothesis. A conclusion is a summary of what you have learned from an experiment. In drawing your conclusion, you should ask yourself whether the data supports your hypothesis. For example, if you found that your experimental group produced 40 flowers and your control group produced 20 flowers, you could draw the

3 conclusion that the fertilizer increased the number of flowers produced and your hypothesis is correct ( %20Method%20Notes.pdf)

4 STEPS OF THE SCIENTIFIC METHOD Identify the letter of the choice that best completes the statement or answers the question. 1. What is the correct order of the steps in the scientific method. a. Ask questions, make a hypothesis, test the hypothesis, analyze results, draw conclusions, communicate results. b. Ask a question, make a hypothesis, test hypothesis, draw conclusions, analyze results, communicate results. c. Make a hypothesis, test the hypothesis, analyze the results, ask a question, draw conclusions, communicate results. d. Ask a question, analyze results, make a hypothesis, test the hypothesis, draw conclusions, communicate results. 2. A scientist formulates a hypothesis, performs experiments to test his hypothesis, makes careful measurements, and keeps accurate records of his findings.in order to complete this process, the scientist should a. adjust the data to support the hypothesis b. eliminate data that do not support the hypothesis c. write a research paper explaining his theories before performing his experiments, in order to gain funding sources d. evaluate the findings and, if necessary, alter the hypothesis based on his findings, and test the new hypothesis 3. Before beginning a research process, two students gathered information about the effect of greenhouse gases on global warming. - Student A found information in a newspaper article. - Student B found information in several peer-reviewed scientific journals and on three websites. Which statement most likely describes the reliability of the students information? a. Information gathered by student A is more reliable because newspapers are always updated to reflect the most current research. b. Information gathered by student B is more reliable because some of it was gathered from peer-reviewed sources. c. Information gathered by student A is more reliable because it is from a single source without conflicting information. d. Information gathered by student B is more reliable because some of it was found on the internet. 4. In science, an educated guess is called a/an a. hypothesis. c. observation b. question d. conclusion

5 5. A student wondered if butterflies would show any differences in their wing color if, as caterpillars, they were grown in the dark or grown in bright white light. Which statement would be a possible hypothesis for an experiment to test this idea? a. Caterpillars exposed to bright white light will show more blue and green in their wings when they become butterflies than caterpillars kept in the dark.. b. Will caterpillars kept in the dark have brighter wings when they become butterflies than caterpillars exposed to bright white light? c. Ten caterpillars will be kept in the dark and ten caterpillars will be exposed to bright white light and allowed to develop into butterfl ies. d. Results show that caterpillars kept in the dark and those exposed to bright white light had the same wing color when they became butterfl ies. 6. An experiment is described below. A large field at the base of a mountain becomes flooded when heavy rains in the mountains cause a stream to overflow. Each time the flooding occurs, more soil washes away. The owners of the land want to perform an experiment to see if different types of plants could help reduce the soil erosion. They choose five areas of ground that are the same size, the same distance from the stream, have the same slope and the same kind of soil, and receive the same amount of sunlight. The type of plant planted in each area is different for each of the five areas. Measurements of soil erosion will be made each time flooding occurs. The results will be compared after six months. Which hypothesis is being tested in this experiment? a. Soil erosion is affected by the c. Some types of plants reduce soil strength of the wind. b. Flooded areas have greater soil erosion than areas that are not flooded. erosion more than others. d. Some types of soil are more easily eroded. 7. A scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact is a/an a. law. c. experiment b. hypothesis d. theory.

6 8. After gathering the information, two students presented the information to their class. The class gave the students suggestions about how to continue with their experiment. How does this step benefit the investigation? a. Feedback from the class will help them design a better experiment. b. Feedback creates confusion, and will complicate the investigation. c. The students investigation will be unaffected because the class is not carrying out the experiment. d. The investigation will be unchanged because students can use information only from published sources to design the experiment. 9. Which activity would be an appropriate first step when designing an experiment? a. reporting a conclusion based on c. creating a data table to organize multiple experimental trials experimental observations b. researching the problem, using d. repeating the experiment with a information from a variety of different hypothesis sources 10. An investigation was carried out to determine which of three antibacterial soaps is most effective. - Four petri dishes labeled A, B, C, and D were set up. - The same amount and type of bacteria was added to each dish. - Next, 2 ml of a different brand of soap were added to dishes B, C, and D. - Then, 2 ml of water were added to dish A, instead of soap. - The dishes were incubated at 37 C for 24 hours. At the end of the investigation, the amount of bacteria in each dish was determined. Dish D had the least bacteria. It was concluded that the soap in dish D was the most effective soap to use against bacteria. Which statement best describes the validity of this conclusion? a. The conclusion is not valid since the same amount of bacteria was used in each dish. b. The conclusion is valid since too small a sample of bacteria was used in this investigation c. The conclusion is valid since the amounts of bacteria were measured at the end of the investigation. d. The conclusion might not be valid since the investigation was carried out only once. 11. When you decide whether or not the data supports the original hypothesis, you are a. forming a hypothesis c. making observations b. drawing conclusions d. asking questions

7 12. Which statement best expresses a basic scientific assumption? a. Interpretation of experimental results has provided explanations for all natural phenomena b. If a conclusion is valid, similar investigations by other scientists should result in the same conclusion. c. For any conclusion to be valid, the design of the experiment requires that only two groups be compared. d. After a scientist formulates a conclusion based on an experiment, no further investigation is necessary 13. When a scientist shares her findings with other scientists, she is a. analyzing data c. experimenting b. making a hypothesis d. communicating results 14. A broad body of evidence, subject to revisions, supported by different kinds of scientific investigations and often involving the contributions of scientists from different disciplines is necessary to develop a. a law. c. a theory b. a fact d. a prediction 15. In order to be accepted, a scientific theory must be a. widely tested and supported by c. controversial and cause debate. extensive data. b. based on the results of a single d. in line with all previous historical experiment. ideas. 16. In the 18th century, Carolus Linnaeus classified organisms based on their structural similarities. Modern classification determines relationships more accurately because it is based on genetic and other biochemical similarities. This change in classification method best illustrates that a. multiple trials are required to increase the validity of a scientific explanation b. scientific explanations are subject to the ethical view of the scientist proposing them c. peer review is required to validate the results of scientific investigations d. all scientific explanations are tentative and subject to change and improvement

8 17. In the 1920s, two newspaper headlines called attention to a mysterious new illness Don t breathe the air! Mysterious disease affecting thousands is caused by breathing the air in swamps Don t drink the water! Mysterious disease affecting thousands is caused by drinking the water in swamps. Another series of headlines appeared in the 1940s and 50s New technology finds tiny worms on swamp vegetation Tiny worms found in lungs of patients suffering from mysterious swamp disease Mysterious disease known to be caused by worms given name Swamp Lung Disease. Headlines such as these best illustrate the concept that a. scientific explanations are tentative and subject to change b. some newspapers are not honest and report incorrect information on purpose flooded. c. worms can enter the body many different ways d. worms found in swamps should not be used for fishing 18. In an appropriately designed experiment, a scientist is able to test the effect of a. a single variable c. the hypothesis b. multiple variables d. scientific observations 19. All the things in an experiment that must be the same to make it fair are called a. independent variables c. controlled experiments b. dependent variables d. controlled variables or constants

9 20. A scientist who wants to study the effects of fertilizer on plants sets up an experiment. Plant A gets no fertilizer, Plant B gets 5 mg. of fertilizer each day, and Plant C gets 10mg. of fertilizer each day. Which plant is the control group. a. Plant A c. Plant C b. Plant B d. All of them e. None of them 21. A company that manufactures a popular multivitamin wanted to determine whether their multivitamin had any side effects. For its initial study, the company chose 2000 individuals to take one of their multivitamin tablets per day for one year. Scientists from the company surveyed the participants to determine whether they had experienced any side effects. The greatest problem with this procedure is that a. only one brand of vitamin was tested c. the sample size was not large enough b. the study lasted only one year d. no control group was used 22. In an experiment, the one variable that is changed is called the a. experimental variable c. controlled variable b. dependent variable d. independent variable 23. In an experiment, the factor that we measure is called the a. independent variable c. dependent variable b. conclusion d. controlled variable 24. The laboratory setup represented below was used to investigate the effect of light on aquatic plants. Equal amounts of a green water plant were placed in beakers with gascollecting tubes. The beakers were placed in a temperaturecontrolled environment. The light source was placed at different distances from the beakers. After an hour, the amount of gas collected from the plants in each tube was measured and recorded in the data table.

10 Which row in the chart below correctly identifies the variables in this experiment? a. Row (1) c. Row (3) b. Row (2) d. Row (4) 25. A scientist hypothesizes that the temperature at which an alligator's egg is incubated will determine whether the alligator will be male or female. The independent variable is a. the incubator c. the temperature b. the gender of the alligator d. the male alligators 26. A scientist hypothesizes that the temperature at which an alligator's egg is incubated will determine whether the alligator will be male or female. The dependent variable is a. the temperature c. the size of the baby alligators b. the gender of the baby alligators d. the incubator A student set up three experiments to investigate the speed of the reaction between magnesium and dilute acid.

11 Which factor was the student investigating? a. Mass of magnesium ribbon in c. The concentration of the acid grams b. Volume of the acid d. Temperature of the acid 28. A student investigated the reaction between zinc and dilute acid Which experiments show how changing acid concentration affects the rate of the reaction? a. 1 y 2 c. 3 y 4 b. 2 y 3 d. 1 y 4

12 RESOURCES Test Review Unit 0_1 Scientific knowlege Answers

13 Test Review Unit 0_1 Scientific knowlege Key part If you have 12 correct answers from question 1 to 17 and 8 correct answers from question 18 to 28, you can feel confident. 1. a. 11.b. 21. d d. 12.b. 22. d b. 13.d. 23. c a. 14.c. 24. c a. 15.a. 25. c c. 16.d. 26. b c. 17.a. 27. c a. 18.a. 28. d c. 19.d d. 20.a