Scientific method & variables

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  • 1. TheScientific MethodThe Steps to Success
  • 2. The Scientific Method∗ What is the scientific method? ∗ It is a process that is used to find answers to questions about the world around us.
  • 3. ∗ Is there only one “scientific method”? ∗ No, there are several versions of the scientific method. ∗ Some versions have more steps, while others may have only a few. ∗ However, they all begin with the identification of a problem or a question to be answered based on observations of the world around us.
  • 4. ∗ They provide an organized method for conducting and analyzing an experiment.
  • 5. ∗ What is a hypothesis? ∗ It is an educated guess based on observations and your knowledge of the topic. ∗ You state it as a possible answer to a question.
  • 6. ∗ Stated in the “If….., then….” format∗ Example: IF I water three plants with different sodas, THEN the plant that receives Sprite will grow the tallest.
  • 7. ∗ What is data? ∗ It is information gathered during an experiment. ∗ It is organized into a data table and displayed visually as a graph.
  • 8. Graphs∗ BAR GRAPHS: can be used to show how something changes over time or to compare items. ∗ have an x-axis (horizontal) and a y-axis (vertical) ∗ the x-axis has time period or what is being measured ∗ the y-axis has numbers for the amount of stuff being measured. ∗ good when youre plotting data that spans many years (or days, weeks...), has really big changes from year to year (or day to day...), or when you are comparing things.
  • 9. ∗ LINE GRAPHS: can be used to show how something changes over time∗ x-axis has numbers for the time period∗ y-axis has numbers for what is being measured.∗ can be used when youre plotting data that has peaks (ups) and valleys (downs), or that was collected in a short time period.∗ Used for two sets of numerical data (ex: time and temp)
  • 10. Steps of the Scientific Method∗ 1. Choose a problem: State the problem as a question.∗ 2. Research your problem: Read, get advice, and make observations.∗ 3. Develop a hypothesis: Make a prediction about what will happen.∗ 4. Design an experiment: Plan how you will test your hypothesis.
  • 11. ∗ 5. Test your hypothesis: Conduct the experiment and record the data.∗ 6. Organize your data: Create a chart or graph of your data.∗ 7. Draw conclusions: Analyze your data and summarize your findings.
  • 12. Identifying VariablesIndependent VariablesDependent VariablesControlled Variables (Constants)
  • 13. 3 Kinds of Variables∗ Independent Variable – something that is changed by the scientist ∗ What is tested ∗ What is manipulated (changed)
  • 14. ∗ Dependent Variable – something that might be affected by the change in the independent variable ∗ What is observed ∗ What is measured ∗ The data collected during the investigation ∗ “the numbers” ∗ Example: how tall the plant grew, how far the paper airplane flew
  • 15. Example:
  • 16. ∗ Controlled Variable – a variable that is not changed ∗ Also called CONSTANTS ∗Allow for a “fair test” ∗ Everything in the experiment except for the IV should be kept constant
  • 17. Procedure∗ Give a detailed explanation of how you will conduct the experiment to test your hypothesis∗ Be clear about the variables (elements you change) versus your constants (elements that do not change)∗ A control is the group that you use as a comparison to see if change has occurred. ∗ Example: In a medicine study, the group of people who don’t get the medicine are the control group
  • 18. ∗ Be very specific about how you will measure results to prove or disprove your hypothesis. You should include a regular timetable for measuring results or observing the projects (such as every hour, every day, every week)
  • 19. Conclusion∗ Conclusion: your results or findings based on data collected during the experiment∗ Answer your problem/purpose statement∗ What does it all add up to? What is the value of your project?∗ What further study do you recommend given the results of your experiment? What would be the next question to ask?∗ If you repeat this project, what would you change?
  • 20. For Example:Students of different ages weregiven a jigsaw puzzle to puttogether. The scientist wanted tosee if the students’ ages affectedhow long it took to put the puzzletogether.
  • 21. Identify the Variables in this Experiment:∗ Independent Variable (IV): ∗ Ages of the students ∗ Different ages were tested by the scientist∗ Dependent Variable (DV): ∗ The time it took to put the puzzle together ∗ The time was observed and measured by the scientist
  • 22. What were the constants?∗ (1) Same puzzle ∗ All of the participants were tested with the same puzzle. ∗ It would not have been a fair test if some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.∗ Other constants: (2) same location, (3) same stopwatch, (4) same person timing the experiment
  • 23. Another Example:∗ An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.
  • 24. What are the Variables?∗ IV: Sizes of nails ∗ These were changed by the scientist∗DV: Number of paper clips picked up ∗ The number of paper clips observed and counted (measured)∗ Constants: Battery, wire, type of nail ∗ None of these items were changed
  • 25. Let’s Practice!∗ If I use a heavier bowling ball, then the ball will travel faster down the lane.∗ IV: weight of bowling ball∗ DV: speed it traveled down lane
  • 26. ∗ 2) If I use different brands of paper towels, then Bounty will absorb more water per minute than Sparkle or Quilted.∗ IV: brand of paper towel∗ DV: amount of water absorbed per minute
  • 27. ∗ 3) If I put 3 spider plants in different locations, then the plant in the sunlight will grow taller in a one-week period than the plants in the closet and basement.∗ IV: location of the plants∗ DV: height of plants