Purdue University



TEACHER NOTES FOR EXPLORING KINEMATICSIntroductionKinematics is the branch of mechanics concerned with the motion of objects without reference to the forces that cause the motion. It doesn't ask “how did the velocity of the body change?” Only, “by how much did it change?”CarsProjectile launchersGraph matching with motion detectors Moving man simulation Projectile launcher simulation: Relevant 2016 ICP Content StandardsStandard 1: Constant VelocityStandard 2: Uniform AccelerationRelevant Physics 1 StandardsStandard 1: Constant VelocityStandard 2: Constant AccelerationIncluded Materials12 constant velocity cars with batteriesScrew Driver12 RulersTapeConclusion Answers Can something be cut in half infinitely many times? Why?Not physically because eventually we would end up with 1 atom. When that 1 atom is split, there wouldn’t be anything left worth talking about. Mathematically though, we could keep dividing the volume by 2. Units are repeatable quantities that enable us to measure the universe. Understanding our world in terms of units (cells, atoms, pennies, digital/discrete vs analog/continuous)Why are standardized units important?They make communication more effective. Think about machining of parts Standard vs. Metric. Talk about SI system. What errors could have affected the certainty of the measurements?How level the floor is, the battery power of car, reaction time (using different people to measure, dirty floor or wheels, debris in the way. etc.How can the uncertainty of the measurements be minimized?Make measurements in the same place every time, use same person for measurements, clean wheels and floor, start the car behind the starting point, etc.Can measurements ever be perfect? Why?No, you cannot be infinitely accurate or precise. You are limited by your tools and environmental factors out of your control.How is this related to the video?Measurements can sometimes mean life or death!How are the triangles seen in Geogebra relevant to the speed?The ratios of the similar triangle sides are the same which generates the slope interpreted as speed.What is speed?A measurement of motion explaining how much distance is covered with time.EXPERIMENT: EXPLORING KINEMATICSIntroduction “Nothing happens until something moves.”- Albert Einstein, 1879-1955, German scientistMotion is the action of moving by changing position with time.“There is more to life than increasing its speed.”- Mahatma Gandhi, 1869-1948, Indian (from India) leaderSpeed is a measurement of motion.“To be is to be the value of a variable.”- Willard Van Orman Quine, 1908-2000, American philosopherVariables are things that can change.Independent variables are the inputs or causes. ?They are the manipulated variables and are usually graphed on the horizontal or x-axis.Dependent variables are the outputs or effects. ?They are the responding variables and are usually graphed on the vertical or y-axis.Controlled variables are held constant or invariant. ?They are the variables that are not being manipulated nor responding to the manipulations.What variables are involved in measuring motion to find how fast the car is?Variables1. Independent variable (manipulated/input/cause)What variable will be manipulated? ________________________What units will you use for the independent variable? ________________________2. Dependent variable (responding/output/effect)What variable will respond to the manipulation? ________________________What units will you use for the dependent variable? ________________________3. Controlled variable (constant/invariant)What is one variable you will hold constant? ________________________MaterialsRepeatable units (markers, scissors, books, tiles, etc.)Rulers (only for measuring the length of unit used)Stopwatches (phones could be used if there are no distractions)Battery operated carsAt least one computer for each group with Geogebra installed or internet access ProcedureDesign the experiment to determine how fast your car is. Gather the materials needed for the experiment.Find a location for the experiment.Collect data.Graph the data.Analyze the data.Present your findings.Data TrialManipulated variable with unitsResponding variable with units00012345ExtraExtraExtraAnalysisGraph your data below (You can use graphing software like excel or sheets as well).136588571755Dependent variable vs. Independent variable (by convention)00Dependent variable vs. Independent variable (by convention)right1972310Responding (Dependent) variable00Responding (Dependent) variable-70870-39763706510544427186690010795Manipulated (Independent) variable00Manipulated (Independent) variable How fast is your car using your units? (Hint: do you see a pattern with the data?)Measure the length of your unit in cm. Convert your speed to centimeters/second or cm/e up with a general formula supported by your data that you could use for predictions.Use Geogebra and adjust the speed to yours in cm/s. Drag the red and blue dots and discuss what is happening in your group. What do you notice about the triangle formed by the blue lines?Summarize your findings on the chalkboard to present to class.Conclusion Can something be cut in half infinitely many times? Why?Why are standardized units important?What errors could have affected the certainty of the measurements?How can the uncertainty of the measurements be minimized?Can measurements ever be perfect? Why?How is this related to the video?How are the triangles seen in Geogebra relevant to the speed?What is speed? ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download