1. Remote Sensing Activity: Physics from a Rocket-Borne Video Camera Andrew Layden BGSU ACTION Summer Bridge ProgramJuly 22, 2010

2. Outline Scientific Motivation Scientific Motivation Today’s Activity: Today’s Activity: Measure the height of rocket Measure the height of rocket Measure size of other objects on ground Measure size of other objects on ground Tomorrow’s Activity: Tomorrow’s Activity: Find height of rocket on several frames Find height of rocket on several frames Determine its speed and acceleration Determine its speed and acceleration Share and discuss results Share and discuss results

3. Lunar Craters http://www.lpi.usra.edu/expmoon/science/craterstructure.html http://www.lpi.usra.edu/expmoon/science/craterstructure.html Carroll & Ostlie, 1996, Modern Astrophysics Moltke Crater 7 km in diameter Copernicus Crater d = 93 km

4. Mars: Ridges in Gordii Dorsum Region

5. http://mars.jpl.nasa.gov/mro/multimedia/images/?ImageID=3263 120 m

6. Mercury: Crater Machaut http://www.nasa.gov/mission_pages/messenger/multimedia/flyby2_20081007_5.html Larger crater d = 100 km

7. Scientific Motivation How do we know these sizes? How do we know these sizes? No humans have been there No humans have been there No robots on ground to measure No robots on ground to measure Remote Sensing: Remote Sensing: Measure angles to determine sizes Measure angles to determine sizes Colors & spectra  surface composition Colors & spectra  surface composition Texture/reflectivity Texture/reflectivity Changes over time Changes over time Orbiting spacecraft, airplanes, balloons Orbiting spacecraft, airplanes, balloons

8. A = angle (degrees) d = distance (km) s = size (km) Mathematical Relation?

9. A = angle (degrees) d = distance (km) s = size (km) Mathematical Relation!

10. Know d (radar), measure A, compute s: Know d (radar), measure A, compute s: Know s (measured), measure A, compute d: Know s (measured), measure A, compute d: Ways to play the eqn:

11. Outline Scientific Motivation Scientific Motivation Today’s Activity: Today’s Activity: Measure the height of rocket (d) Measure the height of rocket (d) Measure size of other objects on ground Measure size of other objects on ground Tomorrow’s Activity: Tomorrow’s Activity: Find height of rocket on several frames Find height of rocket on several frames Determine its speed and acceleration Determine its speed and acceleration Share and discuss results Share and discuss results

12. Day 1 Look at video… Look at video… Think / plan: Think / plan: What do we know on the ground (s)? What do we know on the ground (s)? How do we measure A? How do we measure A? After 5-10 min, then return & share… After 5-10 min, then return & share…

14. Think / plan: Think / plan: What do we know on the ground (s)? What do we know on the ground (s)? How do we measure A? How do we measure A?

16. Measure sizes on computer screen: object: x o FOV: x fov

17. Make a proportion:

18. Solve for A o :

19. How big is A fov ? Calibrate Calibrate Known size (s) at a known distance (d) Known size (s) at a known distance (d) Calculate A Calculate A Observe video Observe video 123

20. Now your turn… Follow steps (i)-(v) for Day 1 on handout. Follow steps (i)-(v) for Day 1 on handout. Useful Equations: Useful Equations:

21. Outline Scientific Motivation Scientific Motivation Today’s Activity: Today’s Activity: Measure the height of rocket (d) Measure the height of rocket (d) Measure size of other objects on ground Measure size of other objects on ground Tomorrow’s Activity: Tomorrow’s Activity: Find height of rocket on several frames Find height of rocket on several frames Determine its speed and acceleration Determine its speed and acceleration Share and discuss results Share and discuss results

22. Day 2 Do some physics: Do some physics: On one frame, measure d 1 On one frame, measure d 1 On next frame, measure d 2 On next frame, measure d 2 Difference:  d = d 2 - d 1 Difference:  d = d 2 - d 1 If we know the time between frames,  t, we can calculate the rocket’s velocity: If we know the time between frames,  t, we can calculate the rocket’s velocity: d1d1 d2d2 dd

23. Day 2 If you have two velocities: If you have two velocities: From d 1 and d 2, got v 1 From d 1 and d 2, got v 1 From d 2 and d 3, got v 2 From d 2 and d 3, got v 2 Difference:  v = v 2 - v 1 Difference:  v = v 2 - v 1 Calculate the rocket’s acceleration: Calculate the rocket’s acceleration: v1v1 v2v2

24. Now your turn… Follow steps (i)-(vi) for Day 2 on handout. Follow steps (i)-(vi) for Day 2 on handout. Useful Equations: Useful Equations:

25. Last 15 min Organize your thoughts for class discussion. Organize your thoughts for class discussion. Write your results on the board: Write your results on the board: Times of observation (frame #s) Times of observation (frame #s) Velocities Velocities Accelerations Accelerations What did we do right? Wrong? Next time? What did we do right? Wrong? Next time? What else could we do with videos? What else could we do with videos?