Physics 11: Friction is Fun! Lab Activity SELF ASSESSMENT Beginning Developing Accomplished Exemplary

Transcription

1 Partner s name: Physics 11: Friction is Fun! Lab Activity SELF ASSESSMENT Beginning Developing Accomplished Exemplary Hypothesis o Outline a hypothesis o Identify some variables o Formulate a testable hypothesis o Correctly identify most variables o Formulate and explain a testable hypothesis using scientific reasoning o Correctly identify most variables o Formulate and explain a testable hypothesis using correct scientific reasoning o Correctly identify variables Data Graph Conclusion Key Concept o Data is incorrect and/or unclear o Relevant information (variables, units, etc.) is missing and/or incorrect o More than three of the Exemplary criteria are missing or incorrect. o Data is frequently incorrect and/or unclear o Some relevant information (variables, units, etc.) is included o Three of the Exemplary criteria are missing or incorrect. o States whether the theory is supported usually with specific reference to results o Data is mostly correct o Most relevant information (variables, units, etc.) is included o One- two of the Exemplary criteria are missing or incorrect. o Correctly responds to hypothesis using scientific reasoning o Usually states whether the theory is supported with specific reference to results o Data is correct o All relevant information (variables, units, etc.) is included and correct o Axes correctly labelled o Proper placement of independent (X) and dependent (Y) variables o Data correctly plotted o Line/curve of best fit represent data plots o Equation of line of best fit included and correct o Title follows Y vs X, includes description o Correctly responds to hypothesis using correct scientific reasoning o States whether the theory is supported with specific reference to results o If the hypothesis is not supported, a reason is identified This report achieves a level of because TEACHER ASSESSMENT Beginning Developing Accomplished Exemplary Hypothesis o Outline a hypothesis o Identify some variables o Formulate a testable hypothesis o Correctly identify most variables o Formulate and explain a testable hypothesis using scientific reasoning o Correctly identify most variables o Formulate and explain a testable hypothesis using correct scientific reasoning o Correctly identify variables Data Graph Conclusion Key Concept o Data is incorrect and/or unclear o Relevant information (variables, units, etc.) is missing and/or incorrect o More than three of the Exemplary criteria are missing or incorrect. o Data is frequently incorrect and/or unclear o Some relevant information (variables, units, etc.) is included o Three of the Exemplary criteria are missing or incorrect. o States whether the theory is supported usually with specific reference to results o Data is mostly correct o Most relevant information (variables, units, etc.) is included o One- two of the Exemplary criteria are missing or incorrect. o Correctly responds to hypothesis using scientific reasoning o Usually states whether the theory is supported with specific reference to results o Data is correct o All relevant information (variables, units, etc.) is included and correct o Axes correctly labelled o Proper placement of independent (X) and dependent (Y) variables o Data correctly plotted o Line/curve of best fit represent data plots o Equation of line of best fit included and correct o Title follows Y vs X, includes description o Correctly responds to hypothesis using correct scientific reasoning o States whether the theory is supported with specific reference to results o If the hypothesis is not supported, a reason is identified 1

2 Partner s name: Physics 11: Friction is Fun! Lab Activity Pre- lab Questions: 1. Draw a free body diagram of a box moving to the right with constant velocity. Indicate the gravitational force normal force applied force frictional force net force 2. What does kinetic frictional force depend upon? 3. How is weight related to the normal force (F N )? 4. If an object is moving at constant velocity in the horizontal direction, what is the relationship between the applied force and the frictional force? Hints: Pull the object at a constant velocity for approximately 0.5m. Make sure the string and scale stay parallel to the surface. Record ALL your data. PART A: static vs. kinetic friction Purpose: Quantitatively, demonstrate the difference between static and kinetic friction. Surface Force required for the object to START moving Force required for the object to MAINTAIN constant velocity 2

3 Conclusion: Using your data, ANSWER your hypothesis. PART B: Type of surface vs. kinetic friction Purpose: Quantitatively, demonstrate how the type of surface affects the force required for the object to maintain constant velocity. Identify as many controlled variables as possible (minimum 4-5): Mass: Normal Force: Rough cut cedar Sanded cedar 80 grit sandpaper 150 grit sandpaper Carpet Plexiglas Frictional force Coefficient of kinetic friction Conclusion: Using your data, ANSWER your hypothesis. 3

4 PART C: surface area vs. kinetic friction Purpose: Quantitatively, demonstrate how surface area affects the force required for the object to maintain constant velocity. Trial 1 Trial 2 Position of Your Box (Draw a picture) Surface Area (cm 2 ) Frictional force (N) Conclusion: Using your data, ANSWER your hypothesis. PART D: weight vs. kinetic friction Purpose: Quantitatively, demonstrate how weight area affects the force required for the object to maintain constant velocity.. 4

5 Trial 1 Trial 2 Trial 3 Trial 4 Weight (N) Normal force (N) Frictional force (N) Draw a free body diagram for one of your trials showing all forces acting on the system and the numerical values for each force. Graph: Plot the data of frictional force vs. normal force. Remember to label your axes, write a title, draw a line of best fit and calculate the slope on the graph. Title of graph: 5

6 EXPLAIN THE MEANING of the relationship, slope and intercepts: PART E: angle of incline and kinetic friction Purpose: Quantitatively, demonstrate how the angle of incline affects the force required to move the object up to the desk. Mass: Force required to move up the incline Angle of incline Trial 1 Trial 2 Trial 3 Trial 4 Identify the type of relationship between the angle of incline and the force required: Conclusion: EXPLAIN and APPLY this to a real- world example. 6