Porosity- the Philosophy of Life


A philosophy professor stood before his class with items on the table in front of him. When the class began, he picked up a very large and empty jar and proceeded to fill it with rocks. He then asked the students if the jar was full. They agreed that it was.

So the professor then picked up some pebbles and poured them into the jar. He shook the jar lightly. The pebbles of course rolled in to the open areas between the rocks. He then asked the students again if the jar was full. They agreed it was.

The professor picked up some sand and poured it into the jar. Of course, the sand filled up everything else. He then asked once more if the jar was full. The students responded with a unanimous “yes.”

The professor then produced two cans of beer from under the table and proceeded to pour their entire contents into the jar- effectively filling the empty space between the sand. The students laughed. “Now,” said the professor as the laughter subsided, “I want you to recognise that this jar represents your life. The rocks are the important things; Your life, Your health, Your family, things that if everything else was lost and only they remained, your life would still be full. The pebbles are the other things that matter- like your job, your home, your career. The sand is everything else- the small stuff which seems important but is not really that necessary. If you put the sand into the jar first, there is no room for the pebbles or the rocks. The same goes for your life. If you spend all your time on the small stuff, you will never have room for the things that are important to you. Pay attention to things that are critical to your happiness. But if you put the rocks in first; the things that really matter in your life, than your life will be a lot more fulfilling and happier. Set your priorities; the rest is just sand.”

One of the students raised their hand and enquired what the beer represented? The professor smiled, “I am glad you asked. It goes to show, no matter how full your life may seem, there is always room for a couple of beers.”

(Author unknown)

Porosity: The science

Porosity (p) in sediment dynamics is the ratio of the volume of voids, to the total volume. For non-cohesive sediments such as sand, p= 0.3 to 0.4. Well-graded and poorly sorted sediments have a large standard deviation of the mean, with p= 0.3. Poorly graded and well sorted sediments have a small standard deviation of the mean with large porosity, with p=0.4. Coastal engineers often take p=0.35 when the actual value is unknown.

This is a story I heard from David Basco, Old Dominion University, Virginia, USA, during his lectures in Coastal Hydrodynamics and Sediment Transport. In Plymouth, I had the opportunity to meet him and his wife in person, and share with him this photograph of our outreach activity at the National University of Ireland, Galway, a jar full of oranges, marbles and maerl.

Monitoring Earthquakes from in the Classroom

This year, at the Irish Geological Research Meeting (IGRM) in Derry, I saw a presentation which quite amazed me. It was about the Seismology in Schools project, made by Emily Neenan of the Dublin Institute for Advanced Studies (DIAS). This is an international programme, which in Ireland is run by DIAS. Following this presentation, I found out more about the scheme:

What is the Seismology in Schools project?

The Seismology in Schools project is an outreach programme introduced by the Dublin Institute for Advanced Studies to schools around Ireland. School children have the opportunity to make real measurements of earthquakes happening around the world from their own classroom. Students monitor the performance of the seismometer daily and consolidate the learning and data collection techniques outlined in the training days. Students upload the recorded earthquake data to the “IRIS Seismographs in Schools” website to share with other schools in Ireland, UK and USA.

The experience of the project has been that learners become more engaged when they see how earthquakes happen in reality and also learn about them through the media. They gain an understanding of earthquake hazards around the world and reflect upon what can be done by scientists and engineers to mitigate the devastating effects of big earthquakes.

What is a seismometer and how does it measure earthquakes?

A seismometer is a very sensitive instrument that can detect movements of the Earth’s surface. The type of seismometer used in the scheme is an SEP seismometer, available from Mindset instruments (for UK and Ireland). The SEP Seismometer System uses the same basic principle underlying all seismometers, which is that of inertia. Seismic waves from an earthquake make the ground move relative to the recording device. In the case of the SEP seismometer, there is a large mass on the end of a boom: this stays where it is as the ground moves beneath the seismometer, and this relative movement is recorded.
Please would you give us a quick example of a recently recorded earthquake.

For example, there was a recent earthquake of 6.2 on the Richter scale at Mindanao, Philippines in February, which was recorded by a school in Ireland, using their seismometer. The school processed these data and subsequently uploaded to the IRIS website:


How many schools are involved in the scheme?

Currently there are 55 Irish primary and secondary schools in the programme and this has now been extended to include colleges, universities and geo-parks. Internationally, there are over 448 schools participating in this scheme, in UK, USA and Ireland. If you know a school which would like to get involved or are a teacher or educator please see the useful links below and get in touch with IRIS (USA), DIAS (Ireland) or the BGS (UK) via their “Contact forms”.

A map of the schools participating in the Seismology for schools project in Ireland.
A map of the schools participating in the Seismology in Schools project in Ireland.

Useful Links

Dublin Institute for Advanced Studies Seismology In Schools website (Ireland) with IRIS Contact form or by emailing Emily Neenan (eneenan*atsign*cp.dias.ie)
IRIS Seismographs In Schools  website (USA) with IRIS Contact form
British Geological Survey School Seismology project website  (UK) with  BGS Contact form
Mindset seismometers  website


Thank you to Emily Neenan of the Dublin Institute of Advanced Studies, Ireland, for information used as part of this blog post. It has helped us learn about a unique outreach programme, which can potentially inspire the younger generation to study the geosciences plus make us all more earthquake aware!! Happy St Patrick’s Day.