![VICKY
Trial 1
[TIME (s)] Trial 2 Trial 3
Average
Descent Time (s) Mass (g)
Top bun 0.56 0.55 0.43 0.51 20.77
Lettuce 0.66 0.53 0.64 0.61 10.33
Tomato 0.38 0.59 0.51 0.49 9.570
Patty 0.43 0.31 0.28 0.34 25.41
Bottom
bun 0.33 0.60 0.46 0.46 10.57
Entire
burger (by
itself) 0.48 0.51 0.29 0.43 76.65
Bag 2.980
Stand 5.740](https://image.slidesharecdn.com/saopeninquirycomplete-141227203253-conversion-gate02/85/Sa-open-inquiry-complete-12-320.jpg)
Sa open inquiry complete
- 1. V I C K Y L I U , K A T E Y E H , D E N N Y C H O I , A N G U S L I N SA OPEN INQUIRY #1 September 13, 2013 PPT by Vicky Liu Gravity
- 2. Gravity acts on each and every food scrap and leftover we throw away. A report from the United Nations Food and Agriculture Organization released on Sept 11, 2013 claims that food waste contributes to the third highest source of greenhouse gas emissions.
- 4. Determine the value of “g” (gravity) as accurately as possible. Hypothesis: If air resistance is constant, then gravity should be constant regardless of mass.
- 6. Materials O Experiment 1 O MASS: Cardboard “burger” (5 ingredients) O MASS: Empty chip bag O Meter stick O iPad Stopwatch app (accurate to 2 decimal places) O Scale O Experiment 2 O MASS: “Denny’s” cup (Tim Hortons cup with crumpled papers inside; this will be clipped and tied on to the string hanging off from the edge of the pole) O Pole stand O Scissors O String O Tape O iPad Stopwatch app O Scale
- 7. Dropping Method: Procedure & Process 1. Hold the item you wish to drop at the determined height 2. Make sure your partner is ready to record with the timer 3. Count to 3 with your partner and on the count of 3 4. Drop the item 5. Your partner will anticipate its land on the ground and will press stop on the timer when it lands Controlled Variables: Mass, height of drop
- 8. Dropping Method: Formula 𝒔 = 𝒅𝒊𝒔𝒑𝒍𝒂𝒄𝒆𝒎𝒆𝒏𝒕 𝒐𝒇 𝒂𝒏 𝒐𝒃𝒋𝒆𝒄𝒕 𝒖 = 𝒊𝒏𝒊𝒕𝒊𝒂𝒍 𝒗𝒆𝒍𝒐𝒄𝒊𝒕𝒚 𝒕 = 𝒕𝒊𝒎𝒆 𝒕𝒂𝒌𝒆𝒏 𝒂 = 𝒂𝒄𝒄𝒆𝒍𝒆𝒓𝒂𝒕𝒊𝒐𝒏 𝒗 = 𝒇𝒊𝒏𝒂𝒍 𝒗𝒆𝒍𝒐𝒄𝒊𝒕𝒚 Things we know = 𝑣 = 𝑢 + 𝑎𝑡 𝑎𝑡 = 𝑣 − 𝑢 a = v − u t (Newton’s first equation of motion) Things we know = 𝐴𝑣𝑔 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 = 𝑠 𝑡 = 𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 𝑡𝑖𝑚𝑒 𝐴𝑣𝑔. 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 = 𝑢+𝑣 2 = 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 + 𝑓𝑖𝑛𝑎𝑙 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 2
- 9. Put the two equations together, since they both = avg. velocities, 𝑢 + 𝑣 2 = 𝑠 𝑡 𝑠 = 𝑢 + 𝑣 2 𝑡 Isolating s (displacement) Knowing 𝑣 = 𝑢 + 𝑎𝑡 from the first equation of motion, we have: 𝑠 = 𝑢 + 𝑢 + 𝑎𝑡 2 𝑡 𝑠 = 2𝑢 + 𝑎𝑡 2 𝑡 𝑠 = 𝑢 + 1 2 𝑎𝑡 𝑡 𝑠 = 𝑢𝑡 + 1 2 𝑎𝑡2
- 12. VICKY Trial 1 [TIME (s)] Trial 2 Trial 3 Average Descent Time (s) Mass (g) Top bun 0.56 0.55 0.43 0.51 20.77 Lettuce 0.66 0.53 0.64 0.61 10.33 Tomato 0.38 0.59 0.51 0.49 9.570 Patty 0.43 0.31 0.28 0.34 25.41 Bottom bun 0.33 0.60 0.46 0.46 10.57 Entire burger (by itself) 0.48 0.51 0.29 0.43 76.65 Bag 2.980 Stand 5.740
- 13. Mass (g) 4 sig figs Acceleration (m/s^2) 2 sig figs Tomato 9.570 8.2 Lettuce 10.33 5.4 BB 10.57 9.3 TB 20.77 7.6 Patty 25.41 17 Entire 76.65 11 Average: before rounding 9.8 𝒔 = 𝒖𝒕 + 𝟏 𝟐 𝒂𝒕 𝟐 𝟏 𝟐 𝒂 = 𝒔 𝒕 𝟐 𝒂 = 𝟐𝒔 𝒕 𝟐 s = displacement of object (1m) u = initial velocity (0m/s) t = time taken (s) a = acceleration (m/s^2) or gravity Result: Mass is NOT directly or inversely proportional to acceleration.
- 14. 0 2 4 6 8 10 12 14 16 18 20 9.57 10.33 10.57 20.77 25.41 76.65 ExperiemtalValuesforGravity(m/s^2) Tomato/Lettuce/Bottom Bun/Top Bun/Patty/Entire Burger MASS (g) "Burger" Drop-Object Results - Vicky Average Acceleration 9.8m/s^2 Acceleration (m/s^2)
- 15. KATE Trial 1 Time (s) Trial 2 Trial 3 Average Descent Time (s) Mass (g) Top bun 0.43 0.49 0.41 0.44 20.77 Lettuce 0.44 1.2 0.61 0.74 10.33 Tomato 0.38 0.59 0.51 0.49 9.570 Patty 0.41 0.31 0.38 0.37 25.41 Bottom bun 0.43 0.53 0.41 0.46 10.57 Entire burger (by itself) 0.48 0.33 0.39 0.40 76.65 Bag 2.980 Stand 5.740
- 16. 𝒔 = 𝒖𝒕 + 𝟏 𝟐 𝒂𝒕 𝟐 𝟏 𝟐 𝒂 = 𝒔 𝒕 𝟐 𝒂 = 𝟐𝒔 𝒕 𝟐 s= displacement of object (1m) u = initial velocity (0m/s) t = time taken (s) a = acceleration (m/s^2) or gravity Result: Mass is NOT directly or inversely proportional to acceleration. Mass (g) 4 sig figs Acceleration (m/s^2) 2 sig figs Tomato 9.570 10.2 Lettuce 10.33 3.7 BB 10.57 8.2 TB 20.77 15 Patty 25.41 9.6 Entire 76.65 12 Average: Before rounding 9.84=> 9.8
- 17. 0 2 4 6 8 10 12 14 16 9.57 10.33 10.57 20.77 25.41 76.65 ExperiemtalValuesforGravity(m/s^2) Tomato/Lettuce/Bottom Bun/Top Bun/Patty/Entire Burger MASS (g) "Burger" Drop-Object Results - Kate Average Acceleration 9.84m/s^2 Acceleration (m/s^2)
- 18. Assumptions and Limitations Assumptions: Assume that the force of friction due to air resistance is constant Assume that objects are dropped straight down (perpendicular to the ground) Limitations: The accuracy of any measurement made using the meter stick is only certain up to 1 millimetre The iPad stopwatch app used in the experiment can only measure up to a hundredth of a second Human reaction time is approximately 0.15 – 0.30 seconds Vicky: 0.283 seconds SIG FIG 0.28s Kate: 0.314 seconds SIG FIG 0.31s
- 19. WAYS TO MINIMIZE ERROR Six trials for each object – average out the result Alternate who is dropping the object and who is operating the stopwatch Count “1,2,3” together for optimal coordination
- 21. Pendulum Method - Procedure: 1. Prepare a thick, stable string and tightly tie at the tip of the pole 2. Using a paper clip tied to the end of the string, connect the string to the “ Denny’s cup”; put on extra tape to ensure that the cup is in a middle posi tion and stable 3. Making sure the cup is not tilted, bring back the cup horizontally away fr om the pole and let it go; at the same time, use a timer to obtain the amo unt of time taken for each lap when the cup returns to its original positio n (period of pendulum) 4. Run three trials of #3 and run 10 laps for each; record the data 5. Making the string shorter by taping a bit more portion onto the cup, agai n run three trials with 10 laps for each; record the data 6. Measure the length of the pendulum by measuring from the bottom of th e edge of the pole to the CENTRE of the mass (the gravitational force act s upon the central part of the mass) 7. Using the formula, and converting it to isolate “g”, calculate the amount of gravity, “g” for each trial for two different lengths of strings (the stand ard gravity acted upon an object is always 9.8 m/s^2)
- 22. T= 2π x √L/g ; g = 4π^2L/T^2 T = period of pendulum, L = length of the string, g = g ravitational acceleration How formula was converted: T = 2π x √L/g -> square both sides T^2= 4π^2L/g -> isolate g through multiplying each side by g and then dividing each side by T ^2 g = 4π^2L/T^2
- 24. DENNY & ANGUS L: 0.3160 m L: 0.4250 m Period of Pendulum (T) units: s Trial 1 0.9, 1.1, 1.2, 1.2, 1.3, 1.1, 1.2, 1.2, 1.1, 1.2 1.3, 1.3, 1.3, 1.4, 1.2, 1.4, 1.3, 1.3, 1.3, 1.3 Trial 1 Average (AV1) 1.2 (1.15) 1.3 (1.30) Trial 2 1.0, 1.2, 1.3, 1.3, 1.2, 1.3, 1.3, 1.3, 1.2, 1.2 1.1, 1.0, 1.3, 1.3, 1.3, 1.3, 1.3, 1.3, 1.3, 1.4 Trial 2 Average (AV2) 1.2 (1.23) 1.3 (1.26) Trial 1 and Trial 2 gravitational force (m/s^2): 8.7 (9.43/8.25) 9.4 (9.43/7.86) Trial 3 1.1, 1.1, 1.0, 1.2, 1.1, 1.2, 1.3, 1.0, 1.1, 1.3 1.1, 1.2, 1.2, 1.2, 1.4, 1.2, 1.3, 1.4, 1.2, 1.3 Trial 3 Average (AV3) 1.1 (1.14) 1.3 (1.25) Trial 3 gravitational force: 10.3 (9.60) 9.4 (7.98) ** in bracket are the values with 3 sig figs
- 25. 0 2 4 6 8 10 12 1 2 3 GravitationalAcceleration(m/s^2) Trial number Deriving the gravitational force value from periods of pendulum L: 0.3160 m (sig figs) L: 0.4250 m (sig figs) L: 0.3160 m L: 0.4250 m Gravitational force
- 26. Observations/Analysis: The pendulum swings grow smaller as time goes by, pro ving that there is gravity force acting upon the mass. Th e lengths of the strings, as mentioned in the formula, do significantly influence the periods of pendulum since th ere are longer distances for the mass to travel. Despite s uch facts, the gravity force value calculated for each of t he different string lengths were similar, only 0.7m/s^2 amount of fluctuation in the results. Important fact to n ote is that the mass of the object used or the compositio n of it (ex. “Denny cup”) do not influence the results as t he gravitational force acts upon all objects with equal a mount of acceleration.
- 27. We assumed that there was no air resistance during our experiment although we were aware that air resistance was present and was directly proportional to the surface area of the bob. The length of the pendulum cannot be determined exactly as it is prone to human error and it is only able to be calculated up to the 2nd decimal place. The period of the pendulum cannot be determined accurately, as the stop watch may not have been stopped at the highest points of each period. Limiting Error We took into account the reaction time of each person involved in the experiment . We determined the period of the pendulum to the 2nd decimal place. We took 10 periods before averaging them out. We tried different lengths, and determined that as length increases, the period increases as well. We deduced that mass and angle was not a significant factor in our calculations. Assumptions and Limitations
- 28. Thank you for listening and may gravity be on your side!