Practical (1 Viewer)

barcyy

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How would i study for a prac? Would i just need to know aim, hypothesis, method, etc. Or do I have to know additional info and skills? It's on electrical energy in the home so it's highly likely it's on circuits.
 

nancylime

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Prac exams generally focus on how you record the data and manipulate and analyse it.
When drawing a table use a ruler and make sure you enclose the box fully. Allow room to record repeated trials. Use a pencil when you are writing down your results, then go over it in pen later. Don't forget to include units in the header boxes. For graphs, ALWAYS USE AN APPROPRIATE SCALE (increments of (.1, .2, .5, or 1.0 etc. don't use weird numbers like 0.3 because it is hard for the marker). Also ensure you use pencil and plot points with little xs. Make sure you label your axis and include units.
They also often will ask questions about reliability, validity and accuracy.
An experiment is reliable if repeated experiments of the same set up achieve consistent results
An experiment is valid if all variables have been accounted for and controlled
An experiment is accurate if the results you get match results that have been published by professionals
They can also ask about variables, so the independent variable is the one that you change throughout the experiment. The dependant is what you are measuring and the controlled variables are what is kept the same throughout the experiment.
In terms of studying, it would be useful to go over the pracs in your textbook and identify the variables, discuss the validity and reliability of each and draw up results graphs and tables.
I hope this helps!
 

Kaido

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I can tell you the most common pracs are:
- Pendulum (Most marks will be allocated here)
- Motors and generators: Either Transforemers/Induction of AC or both
- Ideas: CRT
 

Crisium

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Scientific Report Layout:

1) Aim:

• Comment on what the experiment is attempting to achieve.

2) Hypothesis:

• An educated guess as to the outcome of the experiment.

3) Materials:

• The equipment and any other items used in the experiment.

4) Variables:

Independent Variable: The variable that is changed during the experiment.

Dependent Variable: The variable which is specifically measured.

Controlled Variable: The variable that is kept constant throughout the experiment.

Graphing With Variables:

- Independent Variable: Horizontal Axis (i.e. X-Axis)

- Dependent Variable: Vertical Axis (i.e. Y-Axis)

5) Risk Analysis:

• Comment on the risks associated with using the equipment and chemicals involved in the investigation, and explain why they pose a risk.

• Provide necessary precautions for the experiment so as to minimise or eliminate the risk.

6) Method:

• The procedure used to carry out the experiment.

7) Results:

• They can be qualitative or quantitative.

8) Conclusion:

• The results were (expected / not expected) – refer to the aim.

• The results (support / do not support) the hypothesis.

9) Discussion:

• Accuracy:

- The experimental data should be compared to the accepted values.

- The instruments used in the experiment affect the accuracy.

- Comment on the possible sources of error.

• Reliability:

- The experiment should be repeated a minimum of 5 times in conjunction with an examination of a consistency in results.

- The experimental data should be compared to others performing the same experiment under the same conditions.

• Validity:

- The investigation should apply accepted laws and mathematical relationships.

- All variables should be controlled, barring the dependent and independent variables.

- The type of analysis of the experimental data should be appropriate.

- The experimental method should be testing the aim whilst being scientifically valid.

General Notes:

Definitions:

Inference: A logical explanation for a problem that takes into account all the known facts and observations.

Generalisation: A broad statement which explains a problem taking into account all the known facts and observations.

Transcription Error: Accidently recording the incorrect value obtained from an electronic device.

Systematic Error: Something within the experiment that causes the readings to be consistently high or low; they are always the same magnitude and sign no matter how often the experiment is repeated. This includes errors in calibration, or a repetitive mistake in experimental technique. It can be minimised through careful experimental techniques and proper understanding of the experiment apparatus. An accurate measurement is one with small systematic error.

Random Error: The unpredictable fluctuation of results, due to rapidly changing external influences, limitations of the readability or sloppiness of an instrument or method. Although this type of error is unavoidable, it can be reduced by good experimental practice and by repeating the measurements many times and taking an average. A precise measurement is one with small random error.

Parallax Error: Not reading the measuring scale properly.

Interpolate: Find data in between the known range of values.

Extrapolate: Find data outside the known range of values.

Reminders:

• The answer to a calculation question should be rounded off to the value with the lowest amount of significant figures in the question. However, this value provided in the question must be used in the actual calculation.
 

barcyy

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I can tell you the most common pracs are:
- Pendulum (Most marks will be allocated here)
- Motors and generators: Either Transforemers/Induction of AC or both
- Ideas: CRT
Well in this case, it's prelim and i'm doing electricity soo it's on circuits..
 

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