Scientific method & variables
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Scientific method & variables






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    Scientific method & variables Scientific method & variables Presentation Transcript

    • The Scientific Method The Steps to Success
    • 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.
    • ∗ 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.
    • ∗They provide an organized method for conducting and analyzing an experiment.
    • ∗ 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.
    • ∗ 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.
    • ∗What is data? ∗It is information gathered during an experiment. ∗It is organized into a data table and displayed visually as a graph.
    • 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 you're 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.
    • ∗ 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 you're 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)
    • ∗ 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. Steps of the Scientific Method
    • ∗ 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.
    • Identifying Variables Independent Variables Dependent Variables Controlled Variables (Constants)
    • ∗Independent Variable – something that is changed by the scientist ∗What is tested ∗What is manipulated (changed) 3 Kinds of Variables
    • ∗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
    • Example:
    • ∗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
    • ∗ 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 Procedure
    • ∗ 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)
    • ∗ 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? Conclusion
    • For Example: Students of different ages were given a jigsaw puzzle to put together. The scientist wanted to see if the students’ ages affected how long it took to put the puzzle together.
    • ∗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 Identify the Variables in this Experiment:
    • ∗ (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 What were the constants?
    • ∗ 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. Another Example:
    • ∗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 What are the Variables?
    • 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
    • ∗ 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
    • ∗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