2. Science Unit 1

3. Unit Contents Section 1 - The Methods of Science Section 2 – Measurement and Mathematics

4. Section 1 The Methods of Science Objectives: Identify the steps scientists often use to solve problems. Learn and apply common scientific methodology nomenclature. Compare and contrast science and technology.

5. Section 1 The Methods of Science What is Science??? Science is a method for studying the natural world. It is a process that uses observation and investigation to gain knowledge about events in nature. Science can be classified according to three main categories. Life science deals with living things. Earth science investigates Earth and space. Physical science deals with matter and energy.

6. Section 1 The Methods of Science As more is learned about the natural world, some of the earlier explanations might be found to be incomplete or new technology might provide more accurate answers. Investigations: Scientists learn new information about the natural world by performing investigations, which can be done in many different ways. Some investigations involve simply observing something that occurs and recording the observations. Other investigations involve setting up experiments that test the effect of one thing on another. Some investigations involve building a model that resembles something in the natural world and then testing the model to see how it acts.

7. Section 1 The Methods of Science The Scientific Method An organized set of investigation procedures is called a scientific method.

8. Section 1 The Methods of Science State the Problem Many scientific investigations begin when someone observes an event in nature and wonders why or how it occurs. Other times, a problem arises from an activity that is not working. The question of “why” or “how” is the problem.

9. Section 1 The Methods of Science Gathering Information Before testing a hypothesis, it is useful to learn as much as possible about the background of the problem. Have others found information that will help determine what tests to do and what tests will not be helpful? Possible sources of information: Books, Scientific Journals, Internet, Subject Matter Experts…

10. Section 1 The Methods of Science Form a Hypothesis A hypothesis is a possible explanation for a problem using what you know and what you observe. A hypothesis must meet the following criteria: 1. It must be an educated guess that predicts an outcome. 2. It must be able to be tested. 3. It must include a rational for the prediction. Hypotheses must be in the “If…then…because…” format. The “If” describes what you will be doing in your investigation… “then” is the outcome (i.e. it relates to your problem…) “Because” is your rational for the outcome.

11. Section 1 The Methods of Science Test the Hypothesis Hypotheses can be tested by making observations, creating models, or by conducting an experiment.

12. Section 1 The Methods of Science Test the Hypothesis In order for an experiment to be valid, it must test for only a single variable, it must keep all other variables constant, and their must be a control in order to compare your results to.

13. Section 1 The Methods of Science Test the Hypothesis In a valid experiment you will test for only 1 independent variable, the variable you change to see how it will affect the dependent variable. The dependent variable is the variable that changes because of changes in the independent variable.

14. Section 1 The Methods of Science Test the Hypothesis A factor that does not change when other variables change is called a constant. A control is the standard by which the test results can be compared.

15. Section 1 The Methods of Science Analyze Data An important part of every experiment includes recording observations and organizing the test data into easy-to-read tables and graphs. If the data are not organized in a logical manner, wrong conclusions can be drawn.

16. Section 1 The Methods of Science Draw Conclusions Based on the analysis of your data, you decide whether or not your hypothesis is supported. If it is supported, repeat the experiment several times. If it is not supported, change your hypothesis, and start the process again. For the hypothesis to be considered valid and widely accepted, the experiment must result in the same data every time it is repeated. Findings are supportable when other scientists perform the same experiment and get the same results.

17. Section 1 The Methods of Science Bias Bias occurs when what the scientist expects changes how the results are viewed. Scientists can lessen bias by running as many trials as possible and by keeping accurate notes of each observation made.

18. Section 1 The Methods of Science Scientific Theories and Laws A scientific theory is an explanation of things or events based on knowledge gained from many observations and investigations. It is not a guess. Scientific theories can change as new information becomes available. A scientific law is a statement about what happens in nature and that seems to be true all the time. Gravity is an example of a scientific law.

19. Section 1 The Methods of Science Science and Technology Technology is the application of science to help people. Technology doesn’t always follow science, however, sometimes the process of discovery can be reversed. Think microscopes… Science and technology do not always produce positive results. The benefits of some technological advances, such as nuclear technology and genetic engineering, are subjects of debate.

20. Section 1 The Methods of Science The Limitations of Science Science can help you explain many things about the world, but science cannot explain or solve everything. Questions about emotions, values, and opinions are not scientific questions. Why??? They cannot be tested!

21. Models Sometimes, scientists cannot see everything that they are testing.Sometimes, scientists cannot see everything that they are testing. They might be observing something that is too large, too small, or takes too much time to see completely.They might be observing something that is too large, too small, or takes too much time to see completely. A model represents an idea, event, or object to help people better understand it.A model represents an idea, event, or object to help people better understand it. Section 1 The Methods of Science

22. Models Physical Models - Physical models, such as miniature volcanoes and steam engines, look like the thing that they model. Mathematical Models - A mathematical model may be made up of numbers, equations, and other forms of data. Charts and graphs are examples of mathematical models. Section 1 The Methods of Science

23. Models Conceptual Models Conceptual models are systems of ideas or comparisons of unfamiliar things with familiar things to help explain unfamiliar ideas. Section 1 The Methods of Science

24. Models Through History Lord Kelvin, who lived in England in the 1800s, was famous for making models.Lord Kelvin, who lived in England in the 1800s, was famous for making models. To model his idea of how light moves through space, he put balls into a bowl of jelly and encouraged people to move the balls around with their hands.To model his idea of how light moves through space, he put balls into a bowl of jelly and encouraged people to move the balls around with their hands. Kelvin’s work to explain the nature of temperature and heat still is used today.Kelvin’s work to explain the nature of temperature and heat still is used today. Section 1 The Methods of Science

25. Section 2 Standards and Measurement Objectives: Contrast accuracy and precision. Identify and describe the SI units of length, volume, time, mass, density and temperature. Convert between related SI units.

26. Section 2 Standards and Measurement What is the difference between accuracy and precision? Accuracy – How close are you to the accepted value.

27. Section 2 Standards and Measurement What is the difference between accuracy and precision? Precision – How close are my measurements to each other.

28. Section 2 Standards and Measurement In science we want both accuracy and precision in our measurements.

29. Section 2 Standards and Measurement In science we use the SI system, or as it is commonly called, the metric system for units of measurement. The SI system has many advantages over the English system of measurement. They are… It is based on values of 10, so it is easy to convert between units. It is based on standards, so that all base units are the same, and can be compared to a single standard. A standard is an exact quantity that people agree to use to compare measurements.

30. Common SI base units and symbols: Mass – Kilogram or kg* Length – Meter or m Temperature – Kelvin or K Convert to Kelvin by adding 273 to the Celsius temperature. Time – Second or s Energy – Joule or J Volume – Liter or L All SI base units except mass are combined with a prefix to show the power of ten that should be used with the unit…We’ll say more on this later.

31. Derived Units Any combination of SI units results in a derived unit. Examples Area = length x width m 2 Volume = length x height x width Volume is the space occupied by an object. Units of volume are usually expressed as liters or cm 3 etc.. Density = mass / volume Density is a measure of the amount of matter in object compared to its volume. Units of density are usually expressed as grams/ cm 3 or some combination.

32. KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit CENTI 0.01 Unit MILLI 0.001 Unit Meters Liters Grams Metric Conversion: Ladder Method How do you use the “ladder” method? 1st – Determine your starting point. 2nd – Count the “jumps” to your ending point. 3rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m 1 2 3 How many jumps does it take? Starting Point Ending Point 4. 1 __. 2 3 = 4000 m

33. Section 2 Standards and Measurement