Plan And Implement Investigations

1. Plan And Implement Investigations 2A plan and implement investigative procedures including asking questions, formulating testable hypotheses, and selecting equipment and technology;

2. Scientific Method Scientific Method is used to solve problems. **Inference- conclusion based on data given**

3. Hypothesis • An explanation that based on observations that can be tested.

4. Theory • A set of related hypotheses that have been tested and supported by many scientific investigations. • Explains the causes of observations that we make • Allows us to make predictions • Events predicted by the theory repeat without variation • Change over time as new data is obtained

5. Making Measurements

6. Additional Instruments Barometer - measures atmospheric pressure Spectrometer - measures absorption of different wavelengths of light.

7. Additional Instruments pH Meter – measures the acidity of a solution

8. Experimental Groups • Control Group: Used as a standard to compare to • Experimental Group: All the variables stay the same except the one being tested.

9. Experimental Variables • Independent Variable – the part of the experiment you change on purpose. Found on x axis • Dependent Variable – the part of the experiment that changes because of the change you made in the independent variable. The part you measure.(on “y” axis) • Constant – Variables that do not change. • Dependent, responding, “y”axis • Manipulated, independent, “x” axis Graph Remember DRY MIX

10. 1.Which two pieces of equipment should be added to the materials list for this activity? • Graduated cylinder and metric ruler • Metric ruler and stopwatch • Magnifying glass and balance • Graduated cylinder and balance

11. 1.Which two pieces of equipment should be added to the materials list for this activity? • Graduated cylinder and metric ruler • Metric ruler and stopwatch • Magnifying glass and balance • Graduated cylinder and balance

12. 2. Which of the following is the most likely hypothesis for the experiment described above? • Vegetation that grows near roadways requires more water than vegetation in other areas. • De-icing solution causes roadways to have more space for vegetation. • Vegetation near roadways changes the effectiveness of de-icing solution. • De-icing solution affects some types of vegetation that grow near roadways.

13. 2. Which of the following is the most likely hypothesis for the experiment described above? • Vegetation that grows near roadways requires more water than vegetation in other areas. • De-icing solution causes roadways to have more space for vegetation. • Vegetation near roadways changes the effectiveness of de-icing solution. • De-icing solution affects some types of vegetation that grow near roadways.

14. 3. Which of these tools is most useful in identifying the wavelengths of visible light? • Convex lens • Spectroscope • Microscope • Concave mirror

15. 3. Which of these tools is most useful in identifying the wavelengths of visible light? • Convex lens • Spectroscope • Microscope • Concave mirror

16. 4. A valid study would include a control group containing — • bean seed, tomato seed, sunflower seed, and water • water and 2% root hormone • water only • bean seed, tomato seed, sunflower seed, water, and 1% root hormone

17. 4. A valid study would include a control group containing — • bean seed, tomato seed, sunflower seed, and water • water and 2% root hormone • water only • bean seed, tomato seed, sunflower seed, water, and 1% root hormone

18. 5. This experiment probably was set up to determine — • how much mechanical energy the battery produces • the pH of water during electrolysis • the pressure created by an electric current • how much energy is converted to heat

19. 5. This experiment probably was set up to determine — • how much mechanical energy the battery produces • the pH of water during electrolysis • the pressure created by an electric current • how much energy is converted to heat

20. 6. The table shows times required for water to evaporate from identical containers. Which of these is the best question to ask before developing a reasonable hypothesis to explain the data? • Why does a lower temperature slow the rate of evaporation? • What is the boiling point of the water after both samples are heated? • Why does water exist as a solid at -15C and as a liquid at 25C? • How does the rate of evaporation change when a different container is used?

21. 6. The table shows times required for water to evaporate from identical containers. Which of these is the best question to ask before developing a reasonable hypothesis to explain the data? • Why does a lower temperature slow the rate of evaporation? • What is the boiling point of the water after both samples are heated? • Why does water exist as a solid at -15C and as a liquid at 25C? • How does the rate of evaporation change when a different container is used?

22. 7. Two science students discovered that the mass of a sample of acetone in an open beaker decreased within a few minutes. One student hypothesized that the acetone reacted with oxygen to form a gaseous compound that escaped. The other student believed that the acetone evaporated into the air. What should the students do to test these hypotheses? • Combine the hypotheses so they give valid predictions of the acetone’s behavior • Conduct a study of original papers describing the experiments leading to acetone’s discovery • Perform an experiment that attempts to identify the gas above the open beaker • Ask a classmate’s opinion about the chemical and physical properties of acetone

23. 7. Two science students discovered that the mass of a sample of acetone in an open beaker decreased within a few minutes. One student hypothesized that the acetone reacted with oxygen to form a gaseous compound that escaped. The other student believed that the acetone evaporated into the air. What should the students do to test these hypotheses? • Combine the hypotheses so they give valid predictions of the acetone’s behavior • Conduct a study of original papers describing the experiments leading to acetone’s discovery • Perform an experiment that attempts to identify the gas above the open beaker • Ask a classmate’s opinion about the chemical and physical properties of acetone

24. 8. Which is the best question to ask before developing a reasonable hypothesis for the phenomenon shown below? • Why does water crystallize into a solid below 0C instead of remaining a liquid • How will the freezing time from 20C to –15C change if each container is covered? • Why does boiling the water cause it to freeze more quickly when cooled from 20C to –15C? • What is the precise boiling point of the water in Sample A after it has been heated?

25. 8. Which is the best question to ask before developing a reasonable hypothesis for the phenomenon shown below? • Why does water crystallize into a solid below 0C instead of remaining a liquid • How will the freezing time from 20C to –15C change if each container is covered? • Why does boiling the water cause it to freeze more quickly when cooled from 20C to –15C? • What is the precise boiling point of the water in Sample A after it has been heated?

26. 9. The diagram shows an experimental setup. Which of these questions was this experiment designed to answer? • Does water boil when exposed to air? • Will fire turn a gas into a liquid? • Does air expand when heated? • Will heat turn a gas into a solid

27. 9. The diagram shows an experimental setup. Which of these questions was this experiment designed to answer? • Does water boil when exposed to air? • Will fire turn a gas into a liquid? • Does air expand when heated? • Will heat turn a gas into a solid

28. 10. A scientist hypothesizes that the use of a propellant other than the traditional mixture of C, S, and KNO3 will cause a rocket to rise higher into the air. The researcher builds a rocket that uses an alternate propellant. A proper control for the experiment would be an identical rocket that uses — • the traditional propellant • the alternate propellant • no propellants • a mixture of both propellants

29. 10. A scientist hypothesizes that the use of a propellant other than the traditional mixture of C, S, and KNO3 will cause a rocket to rise higher into the air. The researcher builds a rocket that uses an alternate propellant. A proper control for the experiment would be an identical rocket that uses — • the traditional propellant • the alternate propellant • no propellants • a mixture of both propellants

30. 11. In addition to a hot plate and beakers, which of these items are needed to test the hypothesis above? • Test tube, barometer, thermometer • Balance, thermometer, hand lens • Stopwatch, microscope, test tube • Thermometer, stopwatch, balance

31. 11. In addition to a hot plate and beakers, which of these items are needed to test the hypothesis above? • Test tube, barometer, thermometer • Balance, thermometer, hand lens • Stopwatch, microscope, test tube • Thermometer, stopwatch, balance