Activities

- Physics

- College & CEGEP

- Mechanics

- Group
- Whole Class

- Collecting & seeking information
- Discussing
- Solving problems
- Analyzing

- Computers or interactive whiteboards
- Tracker software
- Excel
- Video with phone
- A bottle rocket

- Small (20-49)

Single class period (< 90 mins)

- Exploration & inquiry

- Collaboration & group work

In this activity, students will be using the Tracker software to analyze the equations of motion of a bottle rocke.

In groups of 3-4, students go outdoors to record a video of a bottle rocket being launched. This is done as a class, however each group will take their own videos. Students should ensure that a distance calibration tool is visible in the video, that the camera is stationary throughout the duration, and that they are far enough back from the bottle rocket that the angular geometry does not interfere significantly with their results. Students should ensure that at least ...

Read More +In this activity, students will be using the Tracker software to analyze the equations of motion of a bottle rocke.

In groups of 3-4, students go outdoors to record a video of a bottle rocket being launched. This is done as a class, however each group will take their own videos. Students should ensure that a distance calibration tool is visible in the video, that the camera is stationary throughout the duration, and that they are far enough back from the bottle rocket that the angular geometry does not interfere significantly with their results. Students should ensure that at least one member of their group is filming using their phone.

Students then return to a computer and upload the video into the Tracker software (for example by emailing themselves the video), and calibrate the axes and distances. They then track the bottle rocket using auto-tracking function of the software (or manually if needed), which produces tabulated data for the position as a function of time.

Students import the data into a spreadsheet program such as Excel. They plot the position as a function of time, then divide the motion into four different stages:

a) Propulsion phase (accelerating upward)

b) Drag (the rocket has a high velocity and drag forces are large)

c) Projectile motion (constant acceleration due to gravity)

d) Terminal velocity.

Students analyze each stage and fit equations of motion to the data. More advanced students can make use of their calculus knowledge to fit first to 2nd order polynomials, then add higher orders.

Students can then see that during certain phases the acceleration was not constant, as it is fit by a higher order polynomial. They discuss the meaning of this and the reasons why the acceleration may not be constant (for example, changing mass and pressure, changing drag forces).

Read Less -Students learn to analyze and fit equations of motion to raw data.

Students learn how to break motion into different regimes based on what forces dominate at any given time.

Published: 18/09/2018

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