Name: Date: 9/18 Period: Unit 1 Science Models & Graphing Essential Questions: What do scientists mean when they talk about models? How can we get equations from graphs? Objectives Explain why models are used in science Describe 3 types of science models Explain the process for how equations come from graphs Practice graphing data using best practices Slide 2 1
Newspapers report about scientists making climate models What does that mean? Video: NASA Taking temperature of the Earth https://youtu.be/jrayigkublg Slide 3 Climate is NOT the same as Weather Weather Changes in our atmosphere over short periods of time (e.g., minutes or months) Climate Average weather for a particular region over long period of time (e.g., 30 years) See article on What s the Difference Between Weather and dcli Climate? https://www.nasa.gov/mission_pages/noaan/climate/climate_weather.html Slide 4 2
Models are useful tools for studying nature The goal of science is to discover the laws of nature, but nature is very complicated. Scientists try to simplify how they study nature. A model is a simpler version of reality: Example: Earth s climate is extremely complex and affected by many factors. If a scientist wants to understand how rising CO 2 levels will affect climate, it is easier to model a smaller part of the Earth system. She may model how higher levels of CO 2 affect plant growth, and then how changes in plant growth affect climate. Slide 5 3 types of scientific models 1. Physical models are smaller and simpler representations of the thing being studied. Example: A globe is a physical model of the Earth. 2. Conceptual models combine ideas into a story or diagram to explain an event. Example: See model of a day after school 3. Mathematical models are equations that include variables to represent an event. Example: Distance Speed Time Note: Climate models do calculations using computers! Slide 6 3
Why are models useful? Used to predict results Example 1: If you know Speed and Time, you can calculate the Distance using this equation Distance Speed Time Example 2: Climate models are useful for trying to predict the changes we can expect as our atmosphere gain more CO 2. Climate models (equations) run on computers because there is so much data and many equations! Slide 7 All models have limitations A model may not accurately predict what happens in all situations because Slide 8 4
Critical Thinking Question How is this model of motion limited? Why wouldn t it work for all types of motion? Distance Speed Time Slide 9 Process for getting equations from graphs (Math Models) 1 Plot the data on a scatter plot. 2 Draw a best fit line. 3 Find the slope and y-intercept. 4 Plug Y and X variables, slope, and y-intercept into: Y mx b Slide 10 5
Skills you need for modeling linear data Graphing Drawing the line of best fit Calculating slope Applying the straight-line formula specific equation for your data Y mx b to get a We will practice and apply these skills this week! Slide 11 4 Graphing Best Practices Graph is 2/3 of page! 1 Heart Rate vs. Exercise Time 1. Title: Use the format Y vs. X. Y is the variable on the Y axis, and X is the variable ibl on the X axis. 2. Label the scale on X and Y axes: Find minimum and maximum X and Y values to make sure all data fits on the graph Each box must be 1, 2, or 5, or multiples 10 of 1, 2, or 5. 3 Heart Rate (be eat/min) 2 Ignore best fit line for now Exercise Time (hr/week) 4 3. Y axis label and units: Show the name of the dependent variable (Y) and its units next to the vertical axis. Units are in parentheses. 4. X axis label and units: Show the name of the independent variable (X) and its units below the horizontal axis. Units are in parentheses. Slide 12 6