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Help on physics project ideas?!

  1. Jan 28, 2016 #1
    I am stumped and I cannot think of any possible experiments that fits the criteria.

    The requirements are:
    -A 10-hour experiment
    -Rigorous and challenging enough for IB-level Physics (A basic college level)

    I tried asking my teacher to do newton's cradle, but she said that it would not fulfill the 10-hour mark. I was also thinking of Newton's Law of cooling, but time again be an issue
  2. jcsd
  3. Jan 28, 2016 #2


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    You have left out significant pieces of information here:

    1. What are the resources available to you to do the experiment? It is a waste of time to suggest something and then you come back telling us "oh, we don't have the equipment or the money to do that".

    2. What exactly are you supposed to show? I mean, there must be something that they want to see rather than just an "experiment".

    3. How handy are you in dealing with equipment and constructing set-ups?

  4. Jan 28, 2016 #3
    Another aspect is what do you like?

    One can stretch any experiment into 10 hours by adding lots of trials to reduce the uncertainties.

    A trick is picking one that needs that amount of time and where the partitioning of time between the set-up and execution makes sense.
  5. Jan 28, 2016 #4
    1) Well we basically have the resources available in a typical high school physics class. We have items for forces and motion (Ex: Air projectile, digital strobes, push pull string, etc), items for light and color, items for analyzing sounds and waves (Ex: tuning forks), items for electrostaics and elecritity (Although i think we may not have a Van de Goff generator), and I am sure we have other materials for the other units, but we have not gotten to them yet. My teacher said she will look at our proposal and see if we have the items we need. Sorry, I do not have a concrete answer for the question :/

    2) Well we are tasked with developing a research question of our choice, designing the experiment, and coming up with an evaluation. They are mainly looking for a rigorous experiment with personal engagement, and the topic is of my choice.

    3) I am fairly handy with set-ups and equipment, but i can always get help from others, including the teachers.

    Thank you very much for the help!
  6. Jan 28, 2016 #5
    I really enjoyed the kinematics unit! However, i am starting to enjoy the electricity unit as well. We have all the materials for various electrical circuits, so maybe one of those topics would be fun. I proposed Newton's cradle to my teacher, but she said that setting up and testing will not be enough. In addition, it must be relatively rigorous compared to the course in order for me to get a high mark. So hopefully multiple trials will be okay, as long as it has a meticulous physics within it.

    And i do agree with your last statement, but i have no clue on what topic i want to do. The only practice lab we have ever done was a lab with a paper helicopter that took a maximum of 10 minutes for all trails, so i have no reference for my experiment.
  7. Jan 28, 2016 #6
    An experiment needs to test a hypothesis. One trick in intro physics is to find a hypothesis that is interesting and not trivial. Another trick is designing an experiment with good accuracy given the available materials. One thing I've noticed over the years is how easy it is to accurately measure time and frequency with the Vernier-type data collectors available in many intro labs, but how much harder it is to accurately measure quantities that are more related to the input amplitude (voltage, temperature, force, sound level, pH, etc.)

    Therefore, if have a Vernier-type device available and you want accuracy to be a strong selling point for your experiment, test a hypothesis that strongly relates to time (period) or frequency and only weakly relates to amplitudes that are harder to measure more accurately than 1-2%. Those Vernier-type devices can easily measure time and frequency to 0.01-0.1% with a good design and a little care.

    An example of an experiment exploiting this strength might be to test the formulas (see: https://en.wikipedia.org/wiki/Pendulum ) relating how the period of a simple pendulum depends on its initial angle of oscillation. If you let T0 be the period of the pendulum with true very small angles, then you can relate T(theta) to it for other initial angles without fumbling about with the accuracy of your length and g estimates (as long as they are constant). Teachers tend to be impressed with experimental designs that succeed in accurately measuring very small differences.

    A few tips on this experiment:

    1. I would hang the pendulum from a force sensor and sample the rate as fast as possible to measure the period.
    2. I would suspend the pendulum from a braided fishing line (20-40 lb power pro or similar) to ensure a constant length. Temperature and humidity of the room need to be approximately constant over the experimental period.
    3. The length of the pendulum is a balance between the number of cycles you want to measure over and how much data the digitizer can store. I would tend to want to sample for 10-20 cycles.
    4. Define your period as twice the time interval from peak force to peak force. Fitting 10-20 data points near the peak to a quadratic will determine the true time of the peak more accurately than inspecting for the single point with the largest force.
    5. You need a mass (pendulum bob) heavy and small enough that you can neglect air resistance, yet light enough that you can completely ignore stretch in the string and stretch in the sensor. You do not want your peak angle changing over the 10-20 cycles of each measurement.

    Lots of other very accurate experiments are possible with Verniers and with the sound cards built into most computers. Last year, I mentored an elementary school student in a science project using Audacity to study the effects of changing temperature on the frequency of a guitar string. The frequency changes are small, but Audacity and a sound card allow for measuring them very accurately (compared with most school physics lab capabilities.)
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