u1l4 - representing data
DESCRIPTION
Science Fusion PowerNotes - Grade 8 Unit 1 Lesson 4 - Representing DataTRANSCRIPT
Unit 1 Lesson 4 Representing Data
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
Indiana Standards
Copyright © Houghton Mifflin Harcourt Publishing Company
• NOS 8.3 Collect quantitative data with appropriate tools or technologies and use appropriate units to label numerical data.
• NOS 8.8 Analyze data, using appropriate mathematical manipulation as required, and use it to identify patterns and make inferences based on these patterns.
• NOS 8.11 Communicate findings using graphs, charts, maps and models through oral and written reports.
Modeling Data with Graphs
Copyright © Houghton Mifflin Harcourt Publishing Company
How do scientists make sense of data?
• All of the different types of scientific investigations involve the collection of data.
• Data are the facts, figures, and other evidence scientists gather when they conduct an investigation.
• Scientists organize and record their data in data tables.
Unit 1 Lesson 4 Representing Data
How do scientists make sense of data?
• Data tables often have two columns.
• One column lists the independent variable, which is the variable that is deliberately manipulated in an investigation.
• The other column lists the dependent variable, which is the variable that changes as a result of manipulation of the independent variable.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
How do scientists make sense of data?
• Scientists often analyze data for patterns or trends by constructing graphs of the data.
• The type of graph they construct depends upon the data they collected and what they want to show.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
How do scientists make sense of data?
• A scatter plot is a graph with points plotted to show a possible relationship between two sets of data.
• In a scatter plot, the horizontal x-axis usually represents the independent variable.
• The vertical y-axis usually represents the dependent variable.
• To show the general relationship between the two variables, a “line of best fit” may be used.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
More Graphing!
Copyright © Houghton Mifflin Harcourt Publishing Company
What do graphs show?
• Scientists use different types of graphs to show different types of information about data.
• A bar graph is used to display and compare data in a number of separate categories.
• A circle graph is used to show how each group of data relates to all of the data.
Unit 1 Lesson 4 Representing Data
Throw Me a Curve!
Copyright © Houghton Mifflin Harcourt Publishing Company
What kinds of patterns can be shown using graphs?• When you graph data, you can identify what the
pattern, or trend, of the data is.
• A trend shows the relationship between the two variables studied in the experiment.
• Graphs make it easy to tell if something is increasing, decreasing, or staying the same.
Unit 1 Lesson 4 Representing Data
What kinds of patterns can be shown using graphs?• In some cases, a line can be used to show the
trend of data on a graph.
• If the relationship between the independent and dependent variables can be shown with a straight line, the graph is called a linear graph.
• A straight line shows that the rate of change of the dependent variable with respect to the independent variable is constant.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
What kinds of patterns can be shown using graphs?
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
• The density of water as a function of temperature is a linear relationship.
What kinds of patterns can be shown using graphs?• A graph in which the relationship between the
variables cannot be shown with a straight line is called a nonlinear graph.
• If the product of variables remains constant, the variables are said to have an inverse relationship.
• A graph of an inverse relationship is a smooth curve that becomes nearly vertical and horizontal at opposite ends.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
What kinds of patterns can be shown using graphs?
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
• The relationship between volume and pressure for a gas at a constant temperature is a nonlinear relationship.
The Perfect Model
Copyright © Houghton Mifflin Harcourt Publishing Company
How do scientists select models?
• Scientists use many different kinds of models.
• Some are physical models, such as maps and globes.
• Others are mathematical models, including equations and simulations of movement.
Unit 1 Lesson 4 Representing Data
How do scientists select models?
• A model is a representation of an object or a process that allows scientists to study something in greater detail.
• A model that is too simple or too complicated may not be useful.
• The best models are those that most closely resemble the system, process, or other entity they represent.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data
How do scientists select models?
• Scientists select models based on how much the models can explain.
• In addition, scientists select models based on how few limitations they have.
• Today, many phenomena in science can be modeled with great sophistication.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 4 Representing Data