Research Methods
Research Methods: Introduction to Error Analysis
Name______________________Partners:__________________________________________
Pre-Assessment Questions:
1. You will be using a stopwatch to measure the time it takes objects to fall. What is the
accuracy with which you will be able to measure times with the stopwatch? Please explain your
answer.
2. Please tell me what you know or remember about the relation between the height from which
you drop an object and the time it takes to fall.
Activity 1:
Working with your partners,
1. Drop a ball from a height of 10 cm. Using your stopwatch, measure how long it takes to fall.
Record your answer.
2. Repeat the measurement of part 1 for a height of 20 cm.
3. Repeat the measurement of part 1 for a height of 30 cm.
4. Repeat the measurement of part 1 for a height of 40 cm
5. Repeat the measurement of part 1 for a height of 50 cm
6. Plot time versus height on a graph.
 2008 The University of Texas at Austin
Research Methods
Introduction to Error Analysis
Activity 2:
Name______________________Partners:__________________________________________
Work with your partners. Using your stopwatch, ramp, and ball, design an experiment to find
how long it takes a ball to roll down a ramp. Carry out the experiment you design.
Suggestion: perform all your measurements with the ramp at a single fixed angle.
1. Plot time needed for your object to roll down the ramp versus the distance it rolls.
2. See if you can deduce the mathematical relation between time and distance. You may
perform additional experiments to test your rule.
Final Questions:
1. What is the accuracy with which a person can time events using a stopwatch? Explain your
answer using the results of your explorations.
2. What is a mathematical rule relating the time a ball rolls down a ramp to the distance over
which it rolls?
3. Explain how you might develop a mathematical rule for freely falling objects by conducting
experiments where balls roll down ramps.
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