Free Fall Lab, Day #1
Lesson 7 of 14
Objective: Students will be able to describe the motion of object dropped straight down and thrown upward. They will also be able to state that acceleration due to gravity on Earth is 10 m/s/s.
Unit 2 Quiz
The goal of this lesson is to see where students are at with the basic acceleration concepts through the quiz. Students show how they can apply concepts of acceleration graphically (in position vs. time, velocity vs. time, and acceleration vs. time graphs), diagrammatically (in motion maps), and mathematically (in calculations). They are using multiple science and engineering practices just on the quiz by using models with the graphs and motion maps and computational thinking with the calculations. The second part of this lesson introduces the concept of free fall to students. We begin to look at acceleration in a different way. Throughout the lab stations, students will develop models about free fall motion (SP2), solve problems using data (SP4 & SP5) and give explanations of their thinking as they reflect after the lab (SP7).
To start out the lesson, I have students complete the Unit 2 Quiz individually. This acts as a mid-unit check that combines everything that students have learned so far in the unit from using mathematical models to complete calculations to creating multiple representations of motion based on a position vs. time graph. Students complete this and I give them a formative grade. I give students feedback and a grade in the next class and students can see where they still need to practice before the test at the end of the unit. I split the quiz up into three main sections: calculations, velocity vs. time graph analysis, and creation of multiple representations of motion. I separate the problems in this way because these are the three main topics that they should have learned so they can see what area they need to focus on when they reflect on their quiz grade. The following videos demonstrate how the quiz is divided and how students did overall: Acceleration Quiz-Calculations and Acceleration Quiz- Multiple Representations of Motion.
When students turn in their quiz, I ask that they take out their chromebooks and read the pages on free fall in their Conceptual Physics textbook (pages 53-56). I have them work on the Free Fall Reading Questions as they read through the text. The text focuses on two sections of free fall: How long? and How far?. It walks students through the concepts of free fall related to the distance that it falls, the velocity at any point and the time it takes to fall. I want them to read about free fall because I want students to have some background on it before completing the free fall lab stations. If they do not finish the reading after they have finished the quiz and before the start of the lab, I ask them to finish it for homework.
Free Fall Stations
After all students have turned in their quizzes, I pass out the Free Fall Baseball Station packet. I have students complete this lab as pairs so I give each pair a packet. I want them to work together and turn in a finished product where they both get the same grade so they rely on each other. Before students begin the stations, I like to go through the stations, with Free Fall Stations Lab Signs posted around the room, and model them as well as give important notes for each station.
At the first station, Ruler Reaction Time, students work with their partner to collect the reaction time between a student dropping ruler and the student catching the ruler. To complete this station, one student holds the ruler at 0 centimeters between another students thumb and forefinger. The student holding the ruler drops it without telling the other student and the second student catches it and records the distance the ruler traveled. This station focuses on the students finding "How long?".
At the second station, Hang Time, students find their own hang time by using a green and pink post-it and finding the distance between the two post-its. The green post-it is placed on the wall with the student's arm stretched as far as possible upward. The pink post-it is placed on the fall when they are at the top of their vertical jump. The goal of this station is for students to recognize that they are finding "How long?" but must multiply their answer by two because they are going up and down, twice the distance.
At the third station, Baseball Drop, students take a baseball that has a timer in it and drop it from a height of two meters. This baseball will record the time from when you let go of the timer button to when it hits the ground. The goal of this station is for students to find the acceleration of the ball as it falls to the ground.
At the fourth station, Picket Fence, students take a large picket fence from PASCO and drop it through a photogate to record the velocity and time data. Then students use Plotly to graph the data and come up with an acceleration from the velocity vs. time graph by finding the slope. The goal of this station is for students to find the acceleration of the picket fence as it falls to the ground.
At the final station, Basketball, students first predict the position vs. time, velocity vs. time and acceleration vs. time graphs for a basketball starting at position 0, thrown up in the air and back down. After they make predictions, I help them collect this data using a motion sensor to show the three graphs on the computer. The goal of this station is for students to find the acceleration of the basketball and to recognize what type of motion the basketball is experiencing when going up, at the top and coming down.
Once I have gone through each station modeling, I allow them to have 6 minutes per station. They are able to complete 2 stations before the end of the period. Students will return to the remaining stations in the next class period.