Vertically-vibrated Granular Studies

Topic: Granular Materials

Granular materials are interesting because they can show properties of both fluids and solids. The classic example is sand, but it can be any sample of a bunch of (usually small) grains, or particles, that are of course solid. Researchers have used small beads, pepper, salt, peas, rice, and so on. Think of something like an avalanche, where individual small solid objects 'flow' down the incline - here, solid objects collectively show something more like a liquid flowing.

A really interesting phenomenon happens when one vertically vibrates granular materials. When one does this with small bronze beads or sand, there are certain combinations of frequency and amplitude where a variety of patterns appear. These patterns always remind me of interference patterns of liquids. Small piles that also form patterns also appear, called oscillons.

In order to oscillate granular samples, one can purchase a mechanical oscillator from a variety of supply companies, such as PASCO, Arbor, and others. Many high schools may have some version of this to form mechanical waves on strings or to vibrate Chladni plates. These go for under $200. To drive the oscillator requires function generators; there is a simple sine wave generator from PASCO that goes for $270, or a more robust function generator that is more expensive at around $700. Some people have used speakers to create vibrations. Granular samples can be placed in petri dishes that are attached to the oscillator.

The vibrated granular experiments can be done easily in a school lab or in a student's basement or bedroom! Data collection is most easily done with video techniques. Be sure to have a ruler or some size standard to measure distances, radii, heights of piles (with a camera with a side view of the material).

Research Ideas for vibrated granular materials:

• Classic crating oscillons and multiple patterns by vertically vibrating sand, small beads, bronze powder, or any other granular material. You can vary size of grains, size of container being vibrated, frequency and amplitude combinations, depth of granular materials, mixtures of different sized grains. (an example)
• Patterns in granular materials at high frequencies (an example)
• Patterns that form when experiment is inside a vacuum, or as a function of air pressure if one has a bell jar and vacuum pump
• Behavior of vertically vibrated piles of granulars; any pattern formation and/or avalanching
• Observations and search for patterns/pile formation/avalanching when granular material is falling onto a vertically vibrating surface (compared to a stationary surface).
• Patterns of vertically vibrating granular materials when the experimental setup is rotating
• Patterns of vertically vibrating granular materials when the experimental setup is on a pendulum, or moving (accelerating) horizontally.
• Pattern formation as a function of moisture/dampening of the granular material (such as wet sand; different levels of wetness)
• If multi-sized beads/grains, is there any stratification or segregation of beads when vertically oscillated 
• Mixing properties of the layers of grains when vibrated; if you have different colored sand, for example, make layers by color, and then find out how the mixing takes place among layers. (an example)
• Search for any horizontal movement/drifting/mixing while vertically vibrating. (an example)
• Effect of barriers, compartments, or obstacles in the container on the pattern formation of the vibrated granular materials
• What happens if a granular sample is vibrated back and forth horizontally?

Research Proposals - What should we consider to do good research?

Research Proposal Format

Below is a brief outline of the main format for a typical research proposal. Use it as a guide to determine what your specific research topic will be, and follow the timeline in order to make good, steady progress over the next few months so you can make the most of your effort.

¨      Proposed research question: this needs to be as specific as possible in whatever field of study you choose.  Depending on which area of science you choose to work, you and an ETHS faculty research advisor will sit down to determine how realistic your topic of interest is.  It is imperative early on to determine whether your research can be done at ETHS or if you will need to make outside contact with a research group (e.g. at Northwestern).  You and your advisor will also have to estimate how much of a time commitment is likely to carry out your project. 

¨      Brief descriptive title of proposed research: a direct statement of your research goal.

¨      Reason for research: Why is it important to find an answer to the question? 

¨      Background information on your topic: Provide a summary of information you have found concerning your topic.  Think of things like the research that has already been done in the field, questions remaining from any prior research, brief highlights of any theory(ies) that may exist to explain the phenomenon, etc.  You must show that you have looked through the literature and have found the latest updates in your area of study.  Normally people don’t get funded if they are ‘reinventing the wheel.’

¨      List of References relevant to your topic: keep a running list of all references as you work through the literature.  You will be required to have this list for your final paper, and chances are you will need to go back to certain references throughout the entire research experience.  This includes all textbooks, reference books, journal articles, Internet sources, private communications with teachers or professors, etc.

¨      Any hypothesis(ses) relevant to your research that you are specifically investigating: Describe/explain main points of what you expect to happen in your research based on literature research.

¨      Resources available to you already at ETHS: What equipment, library resources (such as journals, Internet availability, etc.), software, computers, and teachers are going to be available to you at ETHS.  Based on your literature research, it is important to focus on the methodologies and experimental procedures others have already used in your area of interest.  You will either be building off of what others have done or get ideas of other experiments you would like to do, but you need to think about the equipment necessary to investigate your question(s). 

¨      Other resources you think you’ll need to be able to proceed: From your literature searches, what other equipment/resources/software will you need to design an experiment?  Is it affordable (we do have some funds available for research materials)?  Again, this may limit the sophistication of your project dramatically, or even if your project is a possibility at all!  Think of any universities, industrial resources or donations, medical research facilities, national labs, etc., for possibilities.

¨      Potential costs for additional resources: This may or may not be easy to do; your faculty advisor will help with this.

¨      Proposed experiment: What design will it have?  What controls will be in place?  How will you measure relevant quantities?  What are some probable problems/uncertainties you can expect to deal with?  What expected levels of precision will your measurements and, therefore, results have?

¨      Timetable: What are your initial projections and expectations as far as the time needed to carry out the data collection and analysis?  If you are looking towards competitions, note the following approximate dates your report would be due:

Siemens-Westinghouse                      Late September

Regeneron STS                                  Mid-November

JSHS                                                   Late January

¨      Any other concerns for this research: Are live specimens (especially vertebrates) involved?  Any possible dangers (risk of explosions, gases, fire, electric shock, radiation exposure, etc)?  Basically, make a review of safety requirements that you might need to consider.

¨      After compiling and analyzing data, reach logical conclusions and write up a research report!  This is the goal.  By working systematically and consistently through this list, the sections of your final research report will be in place.  All that remains is to touch things up and put the sections coherently together for your report.

As you can see, there are many considerations and details you must think about to do sophisticated research.  This is why it is so important to develop good work habits and stick to a schedule as best you can.  You will be busy with classes (and your schoolwork still must come first), but with discipline and good time management there is no reason why you wouldn’t be able to complete a strong Intel-level project.  Your faculty research advisor will be around through the entire process to assist and encourage you through the difficult periods when everything seems to be going wrong, but the real  work is up to you.

Good luck!