1. The Scientific Method

2. The Scientific Method is a systematic process that scientists use to study the natural world. The Scientific Method is a systematic process that scientists use to study the natural world.

3. Step 1 – Asking a question Scientific questions are questions about the natural world that can be answered using observation, measurement, or controlled investigations. Scientific questions are questions about the natural world that can be answered using observation, measurement, or controlled investigations. They do not involve opinions, values, or judgments. They do not involve opinions, values, or judgments.

4. Examples of Scientific Questions How does the type of apple tree affect how quickly it grows? How does the type of apple tree affect how quickly it grows? How does the amount of water pollution in a river affect the population of fish? How does the amount of water pollution in a river affect the population of fish? How does the composition of soil affect the growth rate of plants? How does the composition of soil affect the growth rate of plants?

5. Check Point Which of the following is a scientific question? Which of the following is a scientific question? A.How does the kind of metal affect its magnet attraction? B.Which kinds of metal make the most attractive jewelry?

6. Step 2 – Forming a Hypothesis A hypothesis is a possible answer to a scientific question or an explanation for a set of observations. A hypothesis is a possible answer to a scientific question or an explanation for a set of observations. A hypothesis must be testable – you must be able to find out if a hypothesis is true or not by performing an investigation or making observations. A hypothesis must be testable – you must be able to find out if a hypothesis is true or not by performing an investigation or making observations. A hypothesis should be written in the form of an “If…then…” statement. A hypothesis should be written in the form of an “If…then…” statement. A hypothesis is not a fact. An investigation can prove a hypothesis to be incorrect. A hypothesis is not a fact. An investigation can prove a hypothesis to be incorrect.

7. Examples of a Hypothesis Scientific Question – Does temperature affect dissolving rate? Scientific Question – Does temperature affect dissolving rate? Hypothesis – If the dissolving rate is related to temperature, then increasing the temperature will increase the dissolving rate. Hypothesis – If the dissolving rate is related to temperature, then increasing the temperature will increase the dissolving rate.

8. Check Point Which of the following is a properly worded hypothesis? Which of the following is a properly worded hypothesis? A.A puddle in the sunlight will completely evaporate 20 minutes faster than a puddle in the shade evaporates. B.If the temperature of water is related to evaporation, then increasing the temperature of the water will increase the rate of evaporation.

9. Step 3 – Designing and Conducting an Experiment Designing an experiment involves developing a step-by-step procedure that can be followed to test a hypothesis. Designing an experiment involves developing a step-by-step procedure that can be followed to test a hypothesis. –A minimum of 3 trials should be conducted. –The investigation should be a controlled experiment, an investigation in which all variables except one remain the same.

10. Step 3 – Designing and Conducting an Experiment During the experiment, data must be collected. During the experiment, data must be collected. –Data are the facts, figures, and other evidence gathered through observations. –A data table provides an organized way to collect and record data.

11. Step 4 – Analyzing the data After the data are collected, they need to be interpreted, or explained. After the data are collected, they need to be interpreted, or explained. Graphs are a useful way to look at quantitative data because they show trends or patterns in the data. Graphs are a useful way to look at quantitative data because they show trends or patterns in the data.

12. Step 5 – Draw Conclusions Drawing a conclusion means making a statement summing up what you have learned from an experiment. Drawing a conclusion means making a statement summing up what you have learned from an experiment. The conclusion must evaluate the hypothesis and must be supported with data collected during the experiment. The conclusion must evaluate the hypothesis and must be supported with data collected during the experiment.

13. Step -5 Draw Conclusions Imagine that you and your lab partner have decided to experiment to see if the strength of Brand Y paper towels is changed when they get wet. Your lab partner saw an advertisement that convinced her that Brand Y paper towels have the same strength no matter if they are wet or dry. Imagine that you and your lab partner have decided to experiment to see if the strength of Brand Y paper towels is changed when they get wet. Your lab partner saw an advertisement that convinced her that Brand Y paper towels have the same strength no matter if they are wet or dry.

14. Step 5 – Draw Conclusions Problem: How does the wetness of a Brand Y paper towels affect its strength? Problem: How does the wetness of a Brand Y paper towels affect its strength? Hypothesis: If the strength of Brand Y paper towel is related to wetness, then the strength of the paper will decrease as the wetness increases. Hypothesis: If the strength of Brand Y paper towel is related to wetness, then the strength of the paper will decrease as the wetness increases.

15. Data: The average mass held by the paper towel before tearing when dry was 87g. The average mass held by the paper towel before tearing when wet was 54g. Data: The average mass held by the paper towel before tearing when dry was 87g. The average mass held by the paper towel before tearing when wet was 54g. Draw Conclusions: The hypothesis that the strength of a paper towel will decrease with increased wetness was correct because the Brand Y paper towel held 87g on average before tearing when dry and only 54g before tearing when dry. Wet Brand Y paper towels are not as strong as dry Brand Y paper towels based on the results of the experiment. Draw Conclusions: The hypothesis that the strength of a paper towel will decrease with increased wetness was correct because the Brand Y paper towel held 87g on average before tearing when dry and only 54g before tearing when dry. Wet Brand Y paper towels are not as strong as dry Brand Y paper towels based on the results of the experiment.

16. Checkpoint You and a friend have decided to experiment to find the effects of chlorinated tap water on the growth rate of the aquarium plant elodea. You and a friend have decided to experiment to find the effects of chlorinated tap water on the growth rate of the aquarium plant elodea. Problem: Problem: How does chlorine affect the growth rate of elodea? How does chlorine affect the growth rate of elodea? Hypothesis: Hypothesis: –If the growth of elodea is related to chlorine, then increasing the amount of chlorine will decrease the growth of the plant.

17. 1.Summarize the data in the graph. 2.Do the data show that your hypothesis is correct or incorrect? 3.Draw a conclusion for this experiment. - Because the elodea plant without chlorine grew 15cm and the plant with chlorine only grew 10cm, the hypothesis that the growth of the plant will decrease as the chlorine increases is correct. Elodea grown in water with chlorine grows more slowly than elodea grown in water with no chlorine based on the results of this experiment.