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Science Focus Lesson SC.5.N.2.2 Practice of Science/ Replication Polk County Public Schools SC.5.N.2.2 Benchmark: Recognize and explain that when scientific investigations are carried out, the evidence produced by those investigations should be replicable by others. Essential Question: How can scientists support each other by replicating experiments others have done? Vocabulary: experiment evidence replicable valid Gathering Valid Evidence Scientists seek answers by testing hypotheses Hypotheses are tested and verified by collecting evidence through experimentation and observation Evidence is a collection of data helpful in forming a conclusion or judgment Evidence must be replicable in order to be considered valid and accurate A hypothesis that is validated by evidence is considered to be correct Replicable Evidence Evidence must be replicable in order to be valid Replication means that trials must be repeated many times in order to establish a pattern which would help to answer a scientific question Scientists conduct hundreds of trials in an experiment. Students conduct at least three trials when they do an experiment…but more trials is even better! Trial Hot Cold 1 5 min 8 min 2 4 min 7 min 3 5 min 7 min 4 6 min 7 min 5 5 min 8 min Replicable Evidence Evidence must be replicable in order to be valid Replication also means that other scientists can repeat the experiment and get the same results Scientists must keep accurate journals so that others can know exactly how to repeat the experiment Scientists must communicate with one another so that they know about one another’s experiments Replicable Evidence can Validate a Hypothesis Evidence is considered valid when… many trials have been performed and a pattern has been established in the data other scientists have conducted the same experiment and gotten the same results Valid evidence helps scientists understand the answers to scientific questions Summarizing Explain to your shoulder partner the importance of evidence being replicable. Partner A will go first for 15 seconds. Partner B will summarize partner A’s answer. Then switch roles. Replicating Experiments Scientists replicate experiments by communicating with other scientists and repeating the experiment in exactly the same way Scientists must use the SAME UNIT OF MEASURE or they will not be able to compare their results Different units of measure make it impossible to replicate the results Trial My Data Your Data 1 820F 260C 2 850F 270C 3 880F 260C 4 840F 280C 5 900F 300C See how different the data looks when one scientist uses customary units and another uses metric units! Replicating Experiments Scientists replicate experiments by communicating with other scientists and repeating the experiment in exactly the same way Scientists must use the same TOOLS when they replicate another experiment Different tools make it impossible to replicate the results Replicating Experiments Scientists replicate experiments by communicating with other scientists and repeating the experiment in exactly the same way It is important that the repeated experiment FOLLOW THE PROCEDURES exactly Different procedures makes it impossible to replicate the results Summarizing One Sentence Paraphrase Write what you have learned about replicating evidence in one sentence! Share your sentence with your shoulder partner. Guided Instruction: 1. Gabriel is designing an experiment to see whether sugar or artificial sweetener will attract the greatest number of ants. Which statement best describes why Gabriel should write down his experimental procedure? a. b. c. d. The exact experiment can be repeated by others and the results compared. The experiment can be changed by others to get different results. The data will help people decide what type of sweetener to use. The data will show people which ants are more common. The answer is It is important to write very specific procedures so that others can replicate the experiment! Guided Instruction: 2. Two scientists were conducting experiments. They each tested the same hypothesis. They made different observations and reached different conclusions. What will the scientists need to do to determine which conclusion is correct? a. b. c. d. Write a new hypothesis. Ask other scientists to do the same experiment. Test other hypotheses. Write two conclusions. The answer is Although the scientists tested the same hypothesis, they did not read one another’s experiments so they did not follow the same procedures Now it is time for them to share their experiments so that others might be able to replicate their results Guided Instruction: 3. Jamal is a research scientist. He works with other scientists to carry out experiments. They repeat experiments over and over again. They compare and contrast their work and results. Why do scientists compare and contrast the results of their work? It helps them reach valid conclusions. b. It helps them become friends. c. It allows them to choose the best data to report. d. It is more fun to work together. a. The answer is Scientists compare and contrast their results to see if their evidence was replicated by other scientists Evidence that is replicated is considered to be valid and can help to answer scientific questions Guided Instruction: 4. Zack and Josh did the same lab activity from their science book. When they compared their data, they found out that they got very different results. What should they do next? throw out their data and copy someone else’s data b. ask the teacher who is correct c. review their experiments to see if they can tell what caused the difference. d. use Josh’s data because he is a better student a. The answer is It is important to understand what differences caused the students to get different results The boy should check their units of measure, the tools that they used, and other parts of their procedure such as time of day, etc. Summarizing Rally Table: Pass a piece of paper and a pencil around the table. Each student adds something that they know about replicating evidence. Check Your Understanding 1. Three scientists in different counties have been trying to find a cure for a disease. Each scientist has been doing a different experiment. What would be the BEST way for these scientists to find a cure quickly? publish their results to show that the other scientists are wrong b. decide which scientist is doing the best experiment and repeat his experiment c. continue working separately so they don’t mix up their experiments d. communicate with each other to explain their work a. Check Your Understanding 2. What would happen if a person did not write clear procedures and someone else tried to copy their experiment? the results would be slightly different b. the results would be the same c. it would be easy to do the same experiment d. there would be no way to replicate the experiment. a. Check Your Understanding 3. Kaitlyn grew plants outside in different soils for her school science fair. She did her experiment three times. Each time, she recorded plant height daily and also wrote observations in an experiment log. The second time she did the experiment, her data was very different from the data in the other two experiments. Which of the following observations in Kaitlyn’s experiment log might explain the difference? a. b. c. d. She watered her plants the same amount each day. It rained for three days during the second experiment. The plants were all grown on the patio behind her house. She followed her procedure very carefully each time Check Your Understanding 4. A famous scientist did an experiment and published his results. When a scientist in another country repeated the experiment he got very different results. What should the second scientist do? tell everyone the first scientist was wrong b. decide his results must be wrong c. review both experiments to determine why the results were different d. change his data to match the famous scientist’s data a. Check Your Answers 1. D 2. D 3. B 4. C Summarizing Write a paragraph to summarize the essential question. Be sure to include a topic sentence and at least 3 supporting sentences. How can scientists support each other by replicating experiments others have done?