Ib Lab - 07 Loaded Metre Rule (dcp)

Clamp International Baccalaureate Physics

4/PSOW

Meter Rul l

Data Analysis - Vibrations of a Loaded Metre Rule Aim: Many experiments use an equation in which one of the factors is raised to a power e.g - Z2, H1.3. The equation could be for example : R = k. Z2 To test if this equation is true we need to plot a log graph from which we can find : (a) the power that Z is raised to (in this case it is 2) (b) the value of the constant k

IB Criteria Assessed Data Processing Criteria assessed

Aspect 1

2

3

Level awarded

Pl (a) Pl (b) DC DPP

This is a good example of the use of mathematics to manipulate data and from it find useful extra information from the results of our experiments.

CE

Use the experimental results below to plot a log graph and test the relationship for a vibrating ruler :

T = k.l3/2 Diagram:

Results: The results in the table below were obtained for the vibrations of a metre rule loaded with a mass M = 0.2 kg as the projecting length, l, was varied. l/m 0.9 0.8 0.7 0.6 0.5

Time for 20 complete vibrations / s 11.5 11.0 11.1 11.0 11.2 9.0 9.7 9.7 9.2 9.4 7.6 7.5 7.1 8.0 7.3 6.8 6.0 6.7 6.0 6.8 5.0 5.6 5.6 5.1 4.7

Data Processing and Presentation: 1. Draw up a table of l and the average time for one vibration (the period), T. 2. Theoretically, T = k.l3/2, where k is a constant depending on mass, M, the dimensions of the crosssection of the metre rule and the elastic properties of the material of the rule. 3. In order to determine the constant k and confirm the form of the relationship in (2.), the equation has to be rewritten in log form. Include this log data in your new table. 4. Plot a suitable graph in order to confirm the relationship T = k.l3/2 5. From your graph, determine the value for n and k Comment on whether these results confirm the theoretical relationship with a value of n = 1.5. Can you suggest any reasons for deviations from the linear relationship expected in (4.)?

© 2006 - Mike Dickinson

8356922.doc

International Baccalaureate Physics

4/PSOW

Internal Assessment Marking Form Crit.

Pl(a)

Pl(b)

DC

DPP

CE

Aspects Research Question: Hypothesis: Variables: c. Identifies a focused c. Relates the hypothesis or c. Selects the problem or research prediction directly to the relevant question. research question and independent p. States the problem or explains it, quantitatively and controlled research question, but it where appropriate. variable(s). is unclear or incomplete. p. States the hypothesis or p. Selects some n. Does not state the prediction but does not relevant problem or research explain it. variables. question or repeats the n. Does not state a n. Does not select general aim provided by hypothesis or prediction. any relevant the teacher. variables. Materials / Control of Variables: Collecting Data: Apparatus: c. Describes a method c. Describes a method that c. Selects appropriate that allows for the allows for the collection apparatus or control of the of sufficient relevant materials. variables. data. p. Selects some p. Describes a method p. Describes a method that appropriate that makes some allows for the collection apparatus or attempt to control the of insufficient relevant materials. variables. data. n. Does not select n. Describes a method n. Describes a method that any apparatus or that does not allow for does not allow any materials. the control of the relevant data to be variables. collected. Collecting / Recording Raw Data: Organising / Presenting Raw c. Records appropriate raw data (qualitative Data: and/or quantitative), including units and c. Presents raw data clearly, uncertainties where necessary. allowing for easy p. Records some appropriate raw data. interpretation. n. Does not record any appropriate raw data. p. Presents raw data but does not Aspect 1 includes units, uncertainties, allow for easy interpretation. significant digits n. Does not present raw data or presents it incomprehensibly. Processing Raw Data: Presenting Processed Data: c. Processes the raw c. Presents processed data appropriately, helping data correctly. interpretation and, where relevant, takes into p. Some raw data is account errors and uncertainties. processed correctly. p. Presents processed data appropriately but with some n. No processing of raw errors and/or omissions. data is carried out or n. Presents processed data inappropriately or major errors are made incomprehensibly in processing. Aspect 2 includes uncertainty bars, max / min slopes (HL), axes with labels and units, best fit line drawn Drawing Conclusions: Evaluating procedure(s) Improving the c. Gives a valid and results: investigation: conclusion, based on the c. Evaluates procedure(s) c. Identifies correct interpretation of and results including weaknesses and the results, with an limitations, states realistic explanation and, where weaknesses or errors. suggestions to appropriate, compares p. Evaluates procedure(s) improve the results with literature and results but misses investigation. values. some obvious p. Suggests only p. States a conclusion that limitations or errors. simplistic has some validity. n. The evaluation is improvements. n. Draws a conclusion that superficial or n. Suggests unrealistic

© 2006 - Mike Dickinson

Level ccc 3 ccp 2 ccn 2 cpp 2 ppp 1 cpn 1 cnn 1 ppn 1 pnn 0 nnn 0

Grade

ccc 3 ccp 2 ccn 2 cpp 2 ppp 1 cpn 1 cnn 1 ppn 1 pnn 0 nnn 0

cc 3 cp 2 cn 1 pp 1 pn 0 nn 0

cc 3 cp 2 cn 1 pp 1 pn 0 nn 0

ccc 3 ccp 2 ccn 2 cpp 2 ppp 1 cpn 1 cnn 1 ppn 1 pnn 0 nnn 0

8356922.doc

International Baccalaureate Physics

misinterprets the results.

© 2006 - Mike Dickinson

4/PSOW

irrelevant.

improvements.

8356922.doc