Uniform Acceleration Lab Practical
Lesson 13 of 14
Objective: Students will be able to use equations and graphs to determine the acceleration and the time for a cart to travel a certain distance down a ramp.
The goal of this lesson is for students to demonstrate their learning from the uniform acceleration unit through a lab task with their group. The groups that students work with are the students that they have been sitting with and working with throughout the unit. Through this activity, I assess my students in a performance task where they use skills like using models, planning and carrying out investigations, analyzing data, using computational thinking and communicating results.
To begin class, I pass out the Uniform Acceleration Lab Practical, one copy per table. I ask one student from each table to read the instructions out loud to his or her group. While giving them time to read, I get the set up ready to show the students the materials they have. When students are done reading, I ask the students to explain what they are doing today. I do this so that I know what they have understood from reading or listening to the instructions.
I then run through the process of how the lab practical will work. I show students that the set-up is the same as in the Motion of an Incline Lab and explain that there will be two parts: first, they must find the acceleration of the cart using any of the graphs or data tables on the screens from DataStudio; second, they are to find the time it takes for the cart to move 10 centimeters. I tell students to choose a 10 centimeter section that occurs during 30-80 centimeters section of the trip in order to get the best results. I also remind students that 15 points of their grade depends on them showing the work of equations and other resources that they use to find the answers to both parts. The other 10 points are for accuracy between their measured and calculated values for time. The goal of this lab practical is to see how they use the data and graphs to find the acceleration of the cart and then how they use that information to find the time it took for the cart to move in their designated 10 centimeter interval. They can use the Equation Cards to help them determine both Part 1 and Part 2.
When we have finished discussing expectations, I ask each group to spend a few minutes creating a plan of how they will find the acceleration of the cart. Students list the equations or the graphs they will use for each section. Once they have come up with a way to find the acceleration, I have them show me the process that they will use. I then allow them to move to the back of the room to their lab station to collect data. I make them come up with a plan so they have an idea of what they are doing when they begin to collect data.
Once the students are in the back of the classroom, I walk around to make sure they are staying on task. I am also there to answer any questions. Many times I am walking around to make sure that DataStudio, the PASCO computer program used to collect data, is working correctly and troubleshooting when it is not. Students use the motion sensors to collect the data to determine the acceleration, using DataStudio. DataStudio provides them with graphs and numerical data for time and velocity. Students then use their data to solve for acceleration and the time it takes the cart to travel their designated distance. I give students a timeline of where they should be about every 10 minutes so that they know how long they have before they must start the "testing" portion of the lab.
Lab Practical Testing
During the last 10 minutes of class I tell students that all groups must call me over and have their test run done by the time the bell rings. By the "testing" portion of the lab practical, they have determined their time from data and calculations and I use two photogates at their designated distance to determine the actual time it takes the cart to accelerate down the ramp. To test the carts, I first ask students to move their photogates to their designated 10 centimeter interval. After their photogates are set up, I switch to a new file in DataStudio that I have set up to collect the data on the time that it took for the cart to pass the 10 centimeter distance. When I have the time data, I calculate the percent error and then I calculate the number of points they get out of 10 based on the rubric on the instructions page of the lab. Students then clean up their lab station before leaving class for the day. I remind students that there is a test the next day and they should review.