Chapter Introduction Lesson 1 Nature of Science Lesson 2 The Scientific Method

1. Chapter Introduction Lesson 1 Nature of Science Lesson 2 The Scientific Method Lesson 3Tools of the Scientist Chapter Wrap-Up

2. How do scientists perform scientific investigations?

3. The Nature of Science • Essential Question • What do scientists do?

4. The Nature of Science • Independent variable • Dependent variable • Scientific theory • Scientific law • Technology • Science • Observation • Inference • Controlled experiment • Model

5. What is Science? • Science is a way of learning about the natural world that provides possible explanations to questions. • Scientists ask questions about the natural world (why, how or when) and try to answer those questions using evidence they gather. • This process is called scientific inquiry.

6. What is Science? (cont.) • Scientific inquiry often starts with an observation about the natural world. • Observationis using one or more of your senses (sight, touch, sound, taste, and smell) to identify or learn about something.

7. What is Science? (cont.) • Observations lead to questions. • Observation: shorter days in winter • Question: Why? • Answer: investigate to find answer

8. What is Science?(cont.) • Science can answer a question only with the information available at the time. • Sometimes the answers to scientific questions are inferred.

9. What is Science?(cont.) • An inferenceis a conclusion formed from available information or evidence. • Ex. Knowing the Earth is tilted, you might infer that the days are shorter in the winter because the Earth is tilted away from the sun during this time.

10. What is Science?(cont.) • Any answer to a scientific question is uncertain because people will never know everything about the world around them. • Scientists modify their explanations as new information becomes available.

11. What is a scientific investigation? • Different types of scientific questions call for different types of investigations (ways of answering a scientific question). • Field study is an investigation in which scientists make observations and collect information outside of the laboratory. • Modelis a representation of an object or an event that is used as a tool for understanding the natural world.

12. What is a scientific investigation? (cont.) • Controlled experiment is a scientific experiment that involves changing one factor and observing its effects on one thing while keeping all other things constant. • This allows scientists to determine a cause-and-effect relationship among the factors (variables) that are changed in the experiment.

13. What is a scientific investigation? (cont.) • Independent variable is the variable that is changed (manipulated) in an experiment. • Dependent variable is the variable that changes as a result of a change in the independent variable. • Scientists try to keep all other variables constant or unchanged.

14. What is a scientific investigation? (cont.) • A controlled experiment must have two groups: • Control group – the independent variable is not changed in this group. • Experimental group – the independent variable is changed in this group. Both groups include the same factors under the same conditions.

15. How do scientists communicate? • It is important for scientists to communicate to others the results of the investigation as well as the methods by which the investigation was done. • This way the work can be repeated by others to make sure the conclusions were correct or to revise the investigation or to perform related investigations.

16. How do scientists communicate? (cont.) • Scientists may publish reports in journals, books, and on the Internet to show other scientists the work that was done. • Scientists may attend meetings where they give presentations about their work. Scientific explanations are accepted only after they have been shown to be reliable and lead to accurate predictions about future investigations.

17. How do scientists communicate?(cont.) • After a scientific explanation has been accepted by the scientific community, a scientific theory is formed. • Scientific theory is a possible explanation for repeatedly observed patterns in nature supported by observations and results from many investigations. • Ex. Einstein’s theory of relativity • Theories in science are supported by observations and results from many investigations.

18. How do scientists communicate?(cont.) • Scientific law is a rule that describes a pattern in nature but does not try to explain why something happens. • Ex. Newton’s laws of Motion. • For an observation to be a scientific law, it must be observed repeatedly.

20. How is science applied? • Although learning the answers to scientific questions is important, the answers do not help people unless that information can be applied in some way. • Technology is the use of science to help people in some way.

21. What are the branches of science? • Science if often divided into three branches: • Physical science, or physics and chemistry, is the study of matter and energy. • Earth Science is the study of Earth and space including processes that occur on Earth and deep within Earth. • Life Science is the study of living things.

22. Which describes an explanation that is based on knowledge gained from many observations and investigation? A. inference B. prediction C. scientific law D. scientific theory

23. The variable that is changed in a controlled experiment is called the A. independent variable B. dependent variable C. control variable D. experimental variable

24. Which term refers to the practical use of scientific knowledge, especially for industrial or commercial use? A. technology B. scientific law C. inference D. critical thinking

25. The Scientific Method • Essential Question • What process do scientists use to gather information?

26. The Scientific Method • Scientific method • Hypothesis • Data

27. What do scientists do? • The scientific method is used by all kinds of scientists to investigate and answer questions. • Scientific method is a series of steps that scientists use when performing an experiment.

28. What do scientists do? (cont.) • Scientists do not always follow all the steps of the scientific method in order. • However, they always keep careful records of what they have done and observed. • Hypothesis is an explanation that can be tested with a scientific investigation.

29. How do scientists test their hypothesis? • Scientists need to collect data. • Data (singular datum) are information that is gathered during an investigation. • Data can be recorded in the form of descriptions, tables, charts, graphs or drawings.

30. How do scientists analyze data? • Scientists review all of the recorded observations and measurements. • They organize the data as a chart such as a table, a graph, a diagram, a map, or a group of pictures. • They look for patterns in the chart that show connections between important variables in the hypothesis being tested. • Make sure to check the data by comparing it to data from other sources.

31. How do scientists draw conclusions? • A conclusion is a statement about whether or not the hypothesis is valid based on the data collected. • Decide if the data clearly support or do not support the hypothesis. • If the results are not clear, rethink how the hypothesis was tested and make a new plan • Record the results to share with others. • Make sure to ask new questions

32. Which is a hypothesis? A.The ball rolled 5 meters in 21 seconds. B. If the ramp is steeper, then the ball will roll faster. C. The ball is red and made of rubber. D. The speed of the ball is calculated by dividing distance by time.

33. If the results from your investigation do not support your hypothesis, what should you do? A. Modify your hypothesis. B. Repeat the investigation until it agrees with your hypothesis. C. You should not do anything. D. Change your data.

34. Tools of the Scientist • Essential Question • How do scientists collect, analyze and communicate data?

35. Tools of the Scientist • Quantitative data • Qualitative data • Description • Explanation • Precision • Consistency • Mean • Median • Range

36. What are types of data? There are two general types of data: • Quantitative data descriptions of the natural world using numbers. • Ex. Length, width, height, mass and weight. • Qualitative dataare descriptions of the natural world using words. • Ex. Colors, smells, textures and tastes.

37. What are types of data? (cont.) • Descriptionis a summary of observations. • Scientists use different types of data, including descriptions, to develop explanations. • Explanation is an interpretation of observations.

38. What are types of data? (cont.) • One way to evaluate quantitative data is to determine whether they are precise. • Precisionis how closely measurements are to each other and how carefully measurements are made. • Are the following measurements precise? 4.2cm, 4.1cm, 4.2cm range is 4.2 - 4.1 = 0.1(good precision)

39. What are types of data? (cont.) • Precision is affected by the measuring tool and the consistency of the person making the measurement. • Consistencyis the ability to repeat a task with little variation.

40. How do scientists collect data? • Scientists use many different tools to collect data. • Rulers and metersticks are used to measure length.

41. How do scientists collect data? (cont.) • Glassware is used to measure volume and hold liquids. • Ex. Beakers, test tubes and graduated cylinders. • Volume is the amount space an object takes up. • Thermometers are used to measure temperature.

42. How do scientists collect data? (cont.) • Balances and Scales are used to measure mass. • Mass is the amount of material in an object. • Computers and the Internet are used to collect, organize, analyze and display data as well as to do research and share scientific information on the Internet.

43. How do scientists collect data? (cont.) • To measure objects, systems of standard unitshave been developed. • A standard unit is a measurement that people agree to use. • Scientists use standard units in the metric system.

44. How to scientists collect data? (cont.) • The metric system is based on units of 10. • Ex. 1 centimeter is divided into 10 millimeters. • Metric units can be converted to smaller or larger metric system units by multiplying or dividing by 10.

45. How do scientists communicate data? • Everyone who deals with numbers, compares measurements or collects data needs an organized way to collect, analyze and display the data. • Graphs are used to organize and summarize data as well as show relationships between data in a visual way. • Ex. Bar graphs, line graphs and circle graphs

46. How do scientists communicate data?(cont.) • Tables are used to display information in rows and columns so it is easier to read and understand. • Statistics are often used to summarize and evaluate data. The mean, median, mode, and range are used to summarize a set of quantitative data.

47. How do scientists communicate data?(cont.) • Meanis the sum of the numbers in a set of data divided by the number of entries in the set. • Median is the middle number in a data set when the data are arranged in numerical order. • Modeis the number that appears most often. • Rangeis the difference between the highest and lowest values in a data set.

48. How can we stay safe in the lab? • In your science class, you will perform many types of investigations. Before performing these investigations, you must learn how to keep yourself and others safe by using safe practices. • Think before you act. • Follow your teacher’s instructions. • Always wear correct protective clothing and equipment for the investigation that you are performing.

49. How can we stay safe in the lab? (cont.) • Know the location of safety equipment. • Always read the directions before you begin. • Always wash hands before and after an investigation. • Use caution when working with animals and treat them with care.

50. Which tool would be best to use to measure the volume of a liquid? A.Meterstick B. Thermometer C. Test tube D. Graduated cylinder