2 1 Using Scientific Models to Predict Speed

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 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 1. Decide what to put on x and y Usually says in your lab 2. 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 3. Plot your points Start with the x value Slide up vertically until you hit the y number Make your point 4. Do NOT connect the dots! Draw a best-fit curve or line (I’ll tell you which one) 5. Make a title for your graph It should relate to your graph

Making a Prediction After making your curve: 1. Find your starting value on your x-axis Must be a place that is one your graph, but you didn’t measure 2. Draw a vertical line until you hit your curve 3. Draw a horizontal line until you hit the y-axis 4. 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