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How to do an experiment

INTRODUCTION TO SCIENCE & THE SCIENTIFIC METHOD. How to do an experiment. What is Science?. The goal of science is to investigate and understand the natural world, to explain events, and to use those explanations to make useful predictions.

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How to do an experiment

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  1. INTRODUCTION TO SCIENCE & THE SCIENTIFIC METHOD How to do an experiment

  2. What is Science? The goal of science is to investigate and understand the natural world, to explain events, and to use those explanations to make useful predictions.

  3. Science is an organized way of using evidence to learn about the natural world.

  4. What is scientific inquiry? Process scientists use to study the world and develop explanations based on evidence.

  5. How is science done? Scientists collect and organize information in a careful, orderly way, looking for patterns and connections between events.

  6. Scientists propose evidence that can be tested by examining evidence. Scientists make an observation by using their senses to gather information.

  7. Observations Qualitative Quantitative A description Color Texture yellow balloon Size blue sky puffy cloud Tells how many • Total amount • Length • Mass 3 objects 2 stars temp: 1500 C

  8. What do scientists do? Scientists use the scientific method which is a series of steps used to solve a problem or answer a question.

  9. What Are Scientific Methods? • Order of the steps can vary- not always the same *Can use all steps or just some- it depends on the investigation! *Steps can be repeated

  10. Scientific Method Steps The problem Form a hypothesis Design a controlled experiment Procedure Collect and record data Analyze the data State your conclusion

  11. The Problem Start with a problem that can be solved scientifically. What makes a boat float? The problem is always written as a question. Why? How? What? How would you find the density of an object? The problem is measurable. Research What do you know? What do you need?

  12. A scientific explanation, an educated guess, or an answer to a question Based on prior knowledge or observations that can be tested in an experiment Written in the form If …. then …. because If a boat can float then its density is less than water because it does not sink. Form a hypothesis

  13. Prediction vs Hypothesis Predictions ARE NOT hypotheses! A hypothesisexplains what did happen. A prediction is made before you test a hypothesis. *It is what you think will happen *It states a cause and effect When predictions are shown to be true, the hypothesis is supported.

  14. Testingthe Hypothesis Can test a hypothesis by doing an experiment Factor anything in an experiment that can influence the outcome

  15. Design a controlled experiment The factors in an experiment that can be changed are called variables. Some example of variables would be : changing the temperature, the amount of light present, time, concentration of solutions used. A controlled experiment works with one variable at a time. If several variables were changed at the same time, the scientist would not know which variable was responsible for the observed results.

  16. An experiment is based on the comparison between a controlled group with an experimental group. These two groups are identical except for one factor. The control group serves as the comparison. It is the same as the experiment group, except that the one variable that is being tested is removed. The experimental group shows the effect of the variable that is being tested.

  17. PRACTICE Example: In order to test the effectiveness of a new vaccine, 50 volunteers are selected and divided into two groups. One group will be the control group and the other will be the experimental group. Both groups are given a pill to take that is identical in size, shape, color and texture. Even though the volunteers are given identical looking pills, the control group will not actually receive the vaccine. Describe the control group. Describe the experimental group. What variables are kept constant? What variable is being changed? This group will receive the vaccine The size, shape, color, and texture of the pill. Whether or not the pill contains the vaccine.

  18. Identify the variables The factor being tested

  19. Independent & Dependent Control – the standard to which the outcome of the test is compared. What is being tested or changed Only have ONE Comes after “If” in the hypothesis The changes that occur because of the experiment It can be observed and measured Is the data that is collected Comes after “then” in the hypothesis

  20. Procedure Make a plan. Test the hypothesis by changing one variable. Collect materials and tools. Follow directions. Gather information through observation, making measurements.

  21. Use senses to make any observations Collect measurable information Record information on a data table Does the data support or not support the hypothesis? Collect and record data

  22. IMPORTANT REMINDER!! Repeat, repeat, repeat! *The more times an experiment is done, the more data there is to support or disprove the hypothesis

  23. Analyze the data Interpret or explain the data with graphs or pictures

  24. Conclusion A logical answer that addresses the original problem, analyzes the data and determines whether or not the data supports the hypothesis. Experiments must be repeated over and over. When repeated, the results should always be the same before a valid conclusion can be reached.

  25. Practice Problem Paper airplanes

  26. Practice Problem The problem Some paper airplanes fly farther than others. What type of paper makes the best airplane?

  27. Practice Problem The problem Form a hypothesis Some paper airplanes fly farther than others. What type of paper makes the best airplane? If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass.

  28. FORM A HYPOTHESIS Practice Problem The problem Some paper airplanes fly farther than others. What type of paper makes the best airplane? If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass. IDENTIFY THE VARIABLES Independent: construction paper Dependent: distance plane traveled Control: force thrown

  29. QUESTIONS What is the difference between the independent and the dependent variables in an experiment? What is the importance of the control?

  30. QUESTIONS Why is it so important that a scientist accurately describes the procedure used in the experiment? In a “controlled experiment”, why must all of the variables, except one, be kept constant throughout the experiment?

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