1. Physics Experiments Lecture 1a *As swift as a Shadow. *String clocks
*Drop Time
Experiments
Lecture 1a
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2. Physics Experiments
At the end of each lab, you will be required to complete a lab report – including:
Format I:
A) Title
B) Aim
C) Theory
D) Experimental Procedure
E) Measurements
F) Results and Conclusions.
G) Addendum (Answers to any lab based questions)
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3. Physics Experiments (con’)
Format II:
A) Title
B) Abstract (Brief Summary)
C) Introduction (Aim and Theory)
D) The Experiment (Procedure and Measurements)
E) Experimental Results and Discussion (Always discuss your results)
F) Addendum (Answers to any lab based questions)
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4. Additional Lab Format:
1) Title
2) Objective
3) Procedure
4) Data
5) Calculations
6) Conclusions
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5. Title: The title should be a short descriptive name -- Try to come up with an interesting and informative title.
Objective: A short paragraph which, in your own words, describes what it is you are to explore/discover/experience/wonder at in the experiment.
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6. Procedure: A brief but complete description of what you did and how you did it. It should include all major steps and provide enough information so that a second party could reproduce the lab by following the steps you listed. Use drawings /pictures to show the basic lab setup.
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7. Data: What you actually “measured
Data: What you actually “measured.” These are the raw, unprocessed measurements you made. (This should be included in your lab notebook)
“Measure what is measurable and make measurable what is not.” ~ Galileo
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8. The data should always be organized in a logical, sensible, readable manner.
Include units.
Your measurements determine the number of significant figures which your results will have, so make sure your measurements reflect their proper level of precision.
Do not present calculated values in the data section. For example you might measure the mass of an object and then calculate its weight. The weight is not data, it is a calculated value. Only the mass should be in the data section. The weight should be displayed in the calculations section of the lab report.
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9. Calculations: This is what you did with the data after you got it; how you used it.
If many calculations are to be made, you may want to display the results in some sort of table.
Often the data will be displayed in a graph. The graph should be part of your calculations.
Graphs should have a title. Each axis must be labeled and the unit indicated. An appropriate scale must be used.
Graphs should be large. The x axis should take up most of the width of the page. The data displayed on the lab should take up most of the x and y scales.
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10. 3. Explain the basic physics concepts that took place in the lab.
Conclusions: Here you present your results. This should be the most extensive section of the lab report.
1. Report the results
2. Discuss whether your results are reasonable. If they aren't, comment on what may have happened to cause any inaccuracies.
3. Explain the basic physics concepts that took place in the lab.
4. Comment on whether you met the objective for the lab.
5. Discuss any problems you encountered.
6. Include your experimental error if appropriate.
7. Discuss what you learned and the meaning of this knowledge.
8. Ask yourself if the results are logical.
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11. Open Ended; Inquiry Based Labs Part 1a
Read the following “two” labs (more information will be given in class) and “one” activity.
These labs/investigations/activities are to be complete outside of class.
Finished Lab reports will be due on the assigned due date. (see teacher)
The first lab is developed around a phrase that comes from a play of Shakespeare. A lot of physics can be found in such writings.
Additional Labs will be conducted in class, with reports done at home.
Enjoy!
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12. Shakespeare
We will be using a quote from Shakespeare as our inspiration for this lab:
Lysander: “Or, if there were a sympathy in choice, War, death, or sickness did lay siege to it, Making it momentany as a sound, Swift as a shadow, short as any dream, Brief as the lightning in the collied night, That, in a spleen, unfolds both heaven and earth; And ere a man hath power to say "Behold!" The jaws of darkness do devour it up: So quick bright things come to confusion.”
A Midsummer Night's Dream Act 1, scene 1, 141–149
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13. Open-Ended/Inquiry based Lab
“As Swift as a Shadow” Lab © Shelp 2013
Investigate the possible speed of a shadow. How swift can a shadow move?
You must create a shadow, make it move, and measure its speed. (Think about how to do this – be creative.)
Try to make the shadow move as fast as possible, but at the same time measurable. (You must be able to measure the quantities.)
Speculate as to how fast a shadow can move from your data and experiments. (Also, do some research – Google)
Write up a lab report, including answers to any addendum questions. Also include the rough data sheets. (Handout, or print out from Shelp.co)
Remember to discuss the current theories on motion and any limits to speed. This requires research on your part. (Google, etc.)
Question: Is it possible to communicate using shadows? (Like a Shadow cell phone, my idea? Think about it!)
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14. Addendum
“The scientific theory I like best is that the rings of Saturn are made of lost airline luggage.” ~ Mark Russel
Discuss the (possible) answers to the following questions in your Lab Report (Think – use logic):
1) Highest possible velocity for a light spot (like a laser spot) or shadow?
2) What is the lowest speed you have observed? Is there a lowest speed in nature? Slowest possible speed? Shortest time interval?
3) Can something stop moving? How would you show it? Is “Absolute Zero” really an example of no motion?
4) Can the universe move? Can “space” itself move? What would happen if it did? Space-quakes?
5) Is the motion of a shadow an example of motion? If so, what type of motion?
6) Would we observe motion if we had no memory?
7) Is motion random? Ordered? Something else?
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15. (Notice the artist medium is “shadows.”
Art by Kumi Yamashita
(Notice the artist medium is “shadows.”
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16. Inquiry (activity) String Clock (Construct this at home and bring in)
Use string of sufficient length and small weights: Attached the weights to the string in such a way that when you drop the string (with weights), the weights will hit the ground at regular intervals (like the constant beat of a ticking clock)
Many say that “Time is deduced by comparing motions.” What do you think about this statement after completing the string clock?
“Where am I?” is a common question; “When am I?” is never asked, not even in other languages. Why? Is your string clock good at answering these questions: “Where am I?” ; “When am I?” How is time related to motion? How is time related to where you are now in space? (Optional: Read the poem “time” at Shelp.co)
Is there a “Nowhere” and a “Nowhen”?
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17. Dimensional Analysis (Recall)
Suppose: Time, t, for an apple to fall is proportional to (~) the initial drop height, h, the mass of the apple, m, and perhaps the acceleration due to gravity, g.
That is suppose: t ~ hα mβ gγ
Find the exponents α (alpha), β (beta), and γ (gamma), that would make this into an equation or formula that could be used to make a prediction and verified by experiment. It may or may not be confirmed by an experiment, but the dimensions on the left and right have to be the same.
Recall solving this problem resulted in an equation:
t1/t2 = Square Root h1/h2 where t1/t2 is the ratio of fall times and h1/h2 is the ratio of drop heights. You want to verify this result. Is it valid? When? How so?
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18. t1/t2 = Square Root h1/h2
Experimentally verify this ratio for drop time and drop height.
Use a Tennis Ball or similar object. (Drop the ball form two different heights and measure the fall time – would this work on an incline plane? (Google Galileo’s incline plane experiments.)
Do multiple trials.
Do multiple heights. Try different object.
Lab report should include all three investigations: a) As swift as a shadow, b) String clock, c) Drop Ratio. Addition parts will be added from lab work done in class.
Enjoy!
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19. Chelsea, MI in a jiffy. Physics: A "jiffy" is the time it takes light to travel one centimeter.
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20. Chelsea, MI in a jiffy.
Physics: A "jiffy" is the time it takes light to travel one centimeter.
Time = Distance/Speed
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