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2.1 Using Scientific Models to Predict Speed. How can you predict the speed of the car at any point on the ramp?. Key Points. Models: Difference types Using them Graphs: Making them Reading them. Why models?. Answer big questions by breaking them into smaller pieces Save money
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2.1 Using Scientific Models to Predict Speed How can you predict the speed of the car at any point on the ramp?
Key Points • Models: • Difference types • Using them • Graphs: • Making them • Reading them
Why models? • Answer big questions by breaking them into smaller pieces • Save money • Avoid mistakes • Understand nature
Scientific Models • Show how variables relate to one another • 4 different types: • Mental • Physical • Conceptual • Graphical
Mental Models • Visualize / imagine what you want to happen • Use these to make hypotheses • Example: • Before kicking a ball to make a goal, you picture the kick and can make adjustments before you even kick it!
Physical Models • Touchable models that we can manipulate and make measurements from • AKA scale models • Example: • Building a small model of a bridge to see how it reacts to things such as wind and weight before spending a ton of money making a real bridge
Conceptual Models • Describe how something works • Descriptive! • Big picture • Example: • Copernicus described how the Earth revolves around the Sun • Galileo, Kepler, and Newton added to this model
Graphical Model • Uses a graph to show the relationship between variables • AKA mathematical model • Terms: • Dependent variable: depends (or changes because of the other variable • On y-axis (vertical one) • Independent variable: variable we are free to set as we want • On x-axis (horizontal one)
Making a Graph • Decide what to put on x and y • Usually says in your lab • Make a scale for each axis • Each square should be the same value • Possible method: • Count number of squares on that axis • Divide your largest value by the number of squares from above • Round to the nearest whole number
Making a Graph • Plot your points • Start with the x value • Slide up vertically until you hit the y number • Make your point • Do NOT connect the dots! • Draw a best-fit curve or line (I’ll tell you which one) • Make a title for your graph • It should relate to your graph
Making a Prediction • After making your curve: • Find your starting value on your x-axis • Must be a place that is one your graph, but you didn’t measure • Draw a vertical line until you hit your curve • Draw a horizontal line until you hit the y-axis • Use the scale to record your predicted speed
Relationships • Four types: • Strong • Weak • Inverse • none
Lab Reminders • Section 1: • Circle the formula! • Choose 8 locations on the ramp • Locations should be at regular intervals • Car always travels the same distance! • Section 2: • For your graph: • Position on the x-axis • Speed on the y-axis
Lab Reminders • Section 4: • Subtract the large number from the small number • It doesn’t have to be predicted - actual