Unit 1 Lesson 2 Scientific Investigations

1. Unit 1 Lesson 2 Scientific Investigations

2. Unit 1Lesson 2 Scientific Investigations Testing, Testing, 1, 2, 3 What are some parts that make up scientific investigations? • Scientists investigate the natural world through experiments and observations. • An experiment is an organized procedure to study something under controlled conditions.

3. AnObservationis the process of obtaining information by using all of the 5 senses. • Sight • Smell • Hearing • Taste • Touch • There are two types of observations: • Qualitative • Quantitative

4. Ohh… This liquid is green and it is leaking from a brown can. I also smell it. Observation Ohh… This liquid is green and it is leaking from a brown can. I also smell something. smell it.

5. Qualitative Observations • Qualitativeobservations describe what we observe. • “Qualitative” = quality (descriptive) • These observations use adjectives to describe something. • Example:The flower has white petals. • Example:Mr. H has brown eyes.

6. Quantitative Observations • Quantitativeobservationsmeasure what we observe. • “Quantitative” = quantity (numerical) • These observations use numbers to measure something in a quantitative way. • Example:The flower has seven petals. • Example:Mr. H has two eyes.

7. Which is better? • Both types of observations are valuable in science. In an experiment though, quantitative observations can be precisely and objectively compared. Qualitative:The road is long. (describes) Quantitative:The road is 5 km long. (measures) • Some things are easier to quantify than others. Scientists use innovative ways of turning qualitative into quantitative.

8. Which is better? • For example, someone might say that a dead fish is smelly. • It is hard to know just how smelly the fish is though. • To make this quantitative, the scientist could ask the person to rate the “smelliness” on a scale of 1-5. • This would then allow you to compare how smelly the fish is!

9. Inferences • Inferences are an explanation for an observation you have made. • They are based on your past experiences and prior knowledge. • Inferences are often changed when new observations are made. • Again, observations are information we gather directly through our five senses….inferences help explain those observations!

10. Based on my observations, I think that this can is old and is leaking a toxic substance. Inference Based on my observations, I think that this can is old and is leaking a toxic substance..

11. Here are some examples! Observation: The grass on the school’s front lawn is wet. Possible inferences: • It rained. • The sprinkler was on. • There is dew on the grass from the morning. • A dog urinated on the grass. All of these inferences could possibly explain why the grass is wet. They are all based on prior experiences. We have all seen rain, sprinklers, morning dew, and dogs going to the bathroom.

12. Here are some examples! Observation: The school fire alarm is going off. Possible inferences: • The school is on fire. • We are having a fire drill. • A student pulled the fire alarm. Again, these are all logical explanations for why the fire alarm is going off.

13. Now you try it! • Observation: A student is sitting in the main office. • Possible inferences: ? Why might a student be sitting there?

14. Practice • What are some observations and inferences about the picture below?

15. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • Scientific investigations may also involve the use of models. • A model is a representation of an object or a system.

16. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • A hypothesis is a testable idea or explanation that leads to scientific investigation. • A scientist may think of a hypothesis after making observations or after reading findings from other scientists’ investigations. • Hypotheses must be carefully constructed so they can be tested in a practical and meaningful way. • Many hypotheses use the “if/then” statements.

17. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • If an investigation does not support a hypothesis, it is still useful. • The information from the investigation can help scientists form a better hypothesis. • Scientists may go through many cycles of testing and analysis before they arrive at a hypothesis that is supported.

18. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • A variable is any factor that can change in a scientific investigation. • An independent variableis the factor that is deliberately manipulated. • A dependent variable changes as a result of manipulation of one or more independent variables (also known as the responding variable). • A controlled variablestays the same throughout the experiment and is not manipulated at all.

19. Sample Experiment Dependent Independent Controlled

20. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • Datais information gathered by observation or experimentation that can be used in calculating or reasoning. • This information may be anything that a scientist perceives through the senses or detects using instruments. • During their investigations, scientists record all their observations, setup, and procedures, so that they will not forget anything.

21. Unit 1Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? • Scientists analyze data to determine the relationship between the independent and dependent variables in an investigation. • Then they draw conclusions about whether the data support the investigation’s hypothesis.

22. Unit 1Lesson 2 Scientific Investigations Many Methods What are some scientific methods? • Scientists do not always use the same steps or same order of steps in every investigation. • They may even repeat some steps.

23. Perform Experiment & Collect and Organize Data Define a Problem or Ask a Question Form a Hypothesis and Make a prediction Indentify Variables Interpret and Analyze Data and Information Do Research & Plan an Investigation Draw and Defend the Conclusion

24. But what happens when the conclusion doesn’t support the hypothesis?

25. Perform Experiment & Collect and Organize Data The Problem or Question Remains the Same Form a NEW Hypothesis and Make a prediction Indentify Variables Interpret and Analyze Data and Information Do Research & Plan an Investigation Draw and Defend the Conclusion

26. Unit 1Lesson 2 Scientific Investigations What are some scientific methods? • Consider one possible path that a scientist might follow while conducting an experiment. • First, the scientist clearly and precisely defines the problem or question that needs to be answered. • Next, the scientist forms a hypothesis and makes predictions about what will happen in the investigation.

27. Unit 1Lesson 2 Scientific Investigations What are some scientific methods? • To test the hypothesis, the investigation must be carefully planned, taking into account the materials and equipment needed. • The scientist must also decide how the independent variable will change and identify other variables that will be controlled.

28. Unit 1Lesson 2 Scientific Investigations What are some scientific methods? • The scientist must also determine how the results of the experiment will be measured. • The data collected in an investigation must be recorded and properly organized. • After the data are collected, the scientist needs to analyze the information and draw conclusions about the results.

29. Unit 1Lesson 2 Scientific Investigations What are some scientific methods? • If the hypothesis is not supported, the scientist may think about the problem some more and come up with a new hypothesis to test. • An experiment may need to be repeated to check for mistakes. • When publishing the results of their investigation, scientists must be prepared to defend their conclusions.

30. Unit 1Lesson 2 Scientific Investigations Life Lessons How are scientific methods used? • Scientific methods are used in physical, life, and Earth sciences. • Scientists carefully choose the setting for an investigation, such as whether to work in the field or in a laboratory. • Scientists may use models when studying things that are very large, very small, or occurring over a long period of time.

31. Unit 1Lesson 2 Scientific Investigations High Quality What are some characteristics of good scientific investigations? • Good scientific investigations share some important characteristics. • Scientific observations should be well-documented and have supporting evidence. • In an experiment, the variables should be controlled as much as possible.

32. Unit 1Lesson 2 Scientific Investigations What are some characteristics of good scientific investigations? • Experiments should be repeated multiple times by the original investigator. • Scientific investigations should also be able to be replicated by scientists not involved with the original work. • Before publishing a study, scientific journals ask other scientists to review the article. This is called peer review.

33. Unit 1Lesson 2 Scientific Investigations How can you evaluate the quality of scientific information? • The most reliable scientific information is published in scientific journals, but it is often difficult to understand. • Reliable books are written by scientists and others who are knowledgeable about a particular field. • Reliable Internet sources are government and academic web pages. Commercial web pages are often unreliable because they are trying to sell something.