chapter introduction lesson 1lesson 1nature of science lesson 2lesson 2the scientific method lesson...
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Chapter Introduction
Lesson 1 Nature of Science
Lesson 2 The Scientific Method
Lesson 3 Tools of the Scientist
Chapter Wrap-Up
How do scientists perform scientific investigations?
Essential Question • What do scientists do?
The Nature of Science
Science
Observation
Inference
Controlled experiment
Model
The Nature of ScienceIndependent variable
Dependent variable
Scientific theory
Scientific law
Technology
• 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.
What is 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.
What are the branches of science?
• Scientific inquiry often starts with an observation about the natural world.
• Observation is using one or more of your senses (sight, touch, sound, taste, and smell) to identify or learn about something.
• Example: Brandon is wearing a red shirt.
What is Science? (cont.)
• Observations lead to questions.
– Observation: shorter days in winter
– Question: Why?
– Answer: investigate to find answer
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.
What is Science? (cont.)
• An inference is 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.
– Example: Briggs coughed, he might have a cold.
What is Science? (cont.)
What is Science? (cont.)
OBSERVATION INFERENCE
Ms. Crane poured water into a cup. The water disappeared by evaporation.
The glass graduated cylinder has a white ring at the top.
The ring is at the top to prevent breakage in case it falls.
More students are wearing red shirts than white shirts
Red shirts are easier to keep clean than white shirts.
Tree branches are on the front lawn. The tree branches were probably blown out of the trees by the wind.
• Description is a summary of observations.
– Scientists use different types of data, including descriptions, to develop explanations.
• Explanation is an interpretation of observations.
What are types of data? (cont.)
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.
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.
• Model is a representation of an object or an event that is used as a tool for understanding the natural world.
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.
• 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.
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.
What is a scientific investigation?
(cont.)
Both groups include the same factors under the same conditions.
• 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.
How do scientists communicate?
• 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.
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.
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.
How do scientists communicate? (cont.)
• Although learning the answers to scientific questions is important, the answers do not help people unless that information can be applied in some way.
How is science applied?
• Technology is the use of science to help people in some way.
A. inference
B. prediction
C. scientific law
D. scientific theory
Which describes an explanation that is based on knowledge gained from many observations and investigation?
A. independent variable
B. dependent variable
C. control variable
D. experimental variable
The variable that is changed in a controlled experiment is called the
A. technology
B. scientific law
C. inference
D. critical thinking
Which term refers to the practical use of scientific knowledge, especially for industrial or commercial use?
Essential Question
• What process do scientists use to gather information?
The Scientific Method
Scientific method
Hypothesis
Data
The Scientific Method
• 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.
What do scientists do?
• 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.
What do scientists do? (cont.)
• 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.
How do scientists test their hypothesis?
• 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.
How do scientists analyze data?
• 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
How do scientists draw conclusions?
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.
Which is a hypothesis?
A. Modify your hypothesis.
B. Repeat the investigation until it agrees with your hypothesis.
C. You should not do anything.
D. Change your data.
If the results from your investigation do not support your hypothesis, what should you do?
Essential Question
• How do scientists collect, analyze and communicate data?
Tools of the Scientist
Quantitative data
Qualitative data
Description
Explanation
Tools of the Scientist
Precision
Consistency
Mean
Median
Range
There are two general types of data:
• Quantitative data descriptions of the natural world using numbers.
– Ex. Length, width, height, mass and weight.
• Qualitative data are descriptions of the natural world using words.
– Ex. Colors, smells, textures and tastes.
What are types of data?
• One way to evaluate quantitative data is to determine whether they are precise.
• Precision is 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)
What are types of data? (cont.)
– Precision is affected by the measuring tool and the consistency of the person making the measurement.
• Consistency is the ability to repeat a task with little variation.
What are types of data? (cont.)
• Scientists use many different tools to collect data.
• Rulers and metersticks are used to measure length.
How do scientists collect data?
• 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.
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.
How do scientists collect data? (cont.)
• To measure objects, systems of standard units have been developed.
– A standard unit is a measurement that people agree to use.
• Scientists use standard units in the metric system.
How do scientists collect data? (cont.)
Metric System base units
Quantity Measured
Unit (symbol)
Length Meter (m)
Mass Gram (g)
Volume Liter (L)
Temperature Degrees
Celsius (°C)
• 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.
How to scientists collect data? (cont.)
Common Metric Unit Prefixes
Prefix Meaning
Kilo – (K) 1,000
Deka – (da) 10
Deci – (d) 0.1
Centi - (c) 0.01
Milli – (m) 0.001
Micro – (µ) 0.000001
• 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
How do scientists communicate data?
• 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.
How do scientists communicate data? (cont.)
– Mean is 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.
– Mode is the number that appears most often.
– Range is the difference between the highest and lowest values in a data set.
How do scientists communicate data? (cont.)
• 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.
How can we stay safe in the lab?
– 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.
How can we stay safe in the lab? (cont.)
A. Meterstick
B. Thermometer
C. Test tube
D. Graduated cylinder
Which tool would be best to use to measure the volume of a liquid?
A. mean
B. range
C. median
D. mode
Which statistic is the middle number in a data set
Visual Summary
Chapter Review
Standardized Test Practice
Scientists conduct scientific investigations to answer questions about the natural world. They use various tools, skills, and a process called the scientific method to perform scientific investigations.
• Science is a way of learning about the natural world.
• Scientists conduct experiments and field studies and build models to answer scientific questions.
• In a controlled experiment, the independent variable is the factor a scientist changes to observe how it affects the dependent variable.
Lesson 1: The Nature of Science
Lesson 2: The Scientific Method
• The scientific method is a process scientists use to answer their questions.
• A hypothesis is a possible explanation for why something occurs. Scientists gather and analyze data to test their hypothesis and draw conclusions about their investigation.
• Scientists use tools to collect precise data.
• Scientists communicate with one another to share important information. They use tables, graphs and statistics to organize and communicate their data.
• Mean, median and range are some of the statistics used to summarize quantitative data.
Lesson 3: Tools of the Scientist
A. gloves
B. fire extinguisher
C. goggles
D. apron
Which will not protect you from acid that spills out of a beaker?
A. technology
B. experiments
C. scientific theory
D. scientific law
What explains something that takes place in the natural world?
A. vague statements
B. repeatable data
C. several likely explanations
D. notes taken after an investigation
Which increases the reliability of a scientific explanation?
A. line graph
B. circle graph
C. metric units
D. bar graph
Which type of display would best show the number of wins for each football team in your school district?
A. median
B. mean
C. range
D. mode
A family has five children. Which statistic would identify the middle child?
A. the rubber ball
B. the height the ball bounces
C. the height from which the ball is dropped
D. the mass of the ball
Mai Lin is conducting an experiment to see if the height from which she drops a rubber ball will affect the height to which the ball bounces. Which is the independent variable in her experiment?
A. line graph
B. circle graph
C. scatter plot
D. bar graph
Which type of graph should be used to show the composition of gasses in Earth’s atmosphere?
A. to identify the middle number in the data set
B. to make sure the procedures were followed correctly
C. to understand the amount of variation in the data set
D. to identify the lowest number in the data set
Why would scientists want to calculate the range of a set of data?
A. The measurement tool used may not be precise.
B. A hypothesis was formed.
C. The scientist used quantitative data.
D. The data was organized in a table.
Why might there be some variation in data collected?
A. hypothesis
B. scientific law
C. model
D. controlled experiment
If you use a computer to make a three-dimensional picture of a building, it is an example of a