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26/6/2022 -Greenland!

Rather cuffed. An infrasound monitor that we built is off to Greenland tomorrow: see post 30/4/2022.


22/6/2022 - A Curious Atmospheric Pressure Pulse

Noticed both Infrasound monitors detected a curious sharp pressure spike at 12:24 U.T.C.

atmospheric pressure pulse atmospheric pressure pulse

No-one seeems to have heard anything, such as a sonic boom.

Time to accelerate plans for a microbarometer station?


5/6/2022 - Holy sonification Batman

We've been exploring techniques to 'visualise' infrasound signals. Sifting frequencies up to the audible range is an interesting alternative to graphical presentation. From Nathan's detection of the Tonga eruption (strictly Hunga Tonga–Hunga Ha'apai). This video is the primary pulse from Tonga sped up 500x. Thanks to for the base code.


26/5/2022 - Who ate all the PIs?

Lead times for Raspberry PIs are stretched to October. This must be having a real impact on industrial and home developers

We are intending to complete the first build of a brand-new new school's project over the summer break and will have to pull a Pi-4 off another project. It is a tribute to the success of the Pi that there are so few alternatives. Interestingly apparently about 50% are used in industrial applications.


14/5/2022 - Association for Science Education

I have not been a member of the British Association for Science Education for many years - tending to work with the Institute of Physics. The ASE arranged the UK displays at SONs_2022 and after meeting so many enthusiastic science teachers in Prague I have rejoined. Hopefully we will be able to contribute something.

The ASE seems rather weighted towards the private sector. I am wryly amused that UK private schools, perceived as citadels of conservative tradition, seem to beat the state sector in nurturing innovate science teaching.


1/5/2022 - A Photo

The boys are making up a little press-release as they are rather chuffed about their award from the Czech Society of Physics, hence we had to take photos.

award from Czech Society of Physics

L->R: Nathan- gap year before reading physics at Durham University, Saul- A-level student, Ian- physics teacher.


30/4/2022 - Portable Infrasound Monitor #3

Portable monitor LBC-1 now under 'soak' testing. Here are sample 24-hour plots of infrasound monitors Alpha, LBC1 & Gamma. Alpha and LBC-1 are next to each other with Gamma 5m away fitted with a different windfilter. LBC-1 is successfully detecting the same signals as the other two though, to eye, the sensitivity is rather higher.

portable infrasound monitor

Will do a proper analysis of frequency response shortly.


22/4/2022 - Portable Infrasound Monitor #2

We have made up and provisionally tested the new portable Infrasound monitor - now named LBC-1. Presently only loosely fitted in a rugged waterproof Pelicase whilst we run it alongside another to compare response and check calibration. We're hoping that this will be used for field measurements in Greenland later this year.

Left is differential mems sensor and real-time clock, right is 'backing volume' on top of a Raspberry Pi in a heat sink case. Bottom is a USB battery.

Infrasound Monitor


22/4/2022 - Infrasound - minor milestone

Infrasound monitor Paper #1 has now been downloaded over 100 times from the I.O.P.


14/4/2022 - Portable Infrasound Monitor #1

Starting to construct a new Infrasound monitor specifically for field measurements. System to fit into a snazzy yellow Pelicase. May try to include a gps module. This should be the most sensitive system we've built to date. Sensor has a resolution of ~0.015 Pa, i.e. about 1/6 millionth of atmospheric pressure and should be able to resolve low frequency sound in the range of <1/100 Hz to >60Hz.

Infrasound Monitor
Infrasound Monitor


28/3/2022 - Science on Stage - Prague 2022

Exhausting but had a wonderful time. After working in isolation for many years I was amazed to see the innovation and enthusasm of over 200 displayed science education projects - all freely available to use, improve and collaborate on. Truly humbling and put my own efforts to shame. The UK delegation had very strong primary science projects. Jasper the Spider by Jules Pottle was delightful - a children's science story book by a biologist. I have bought a copy to read to my sons - they may be 14/17/19 but they're bloody well sitting on the bed to listen to it.

The stands of the Ukrainian delegates were set up, with blue and yellow flags and written summaries - though at least one lady had made it to Prague.

Then came the final awards ceremony. Given the quality of the other participants I was extremely confident of not having to stand up - I'm not good at that sort of thing. However .. the Czech Society of Physics awarded us a medal! I was very embarrassed, humbled and unusually tongue-tied. Wish Nathan and Saul could have come.

I'm hoping that this small publicity will encourage others to take on these projects - esp. the Infrasound monitor which has potential for students to undertake and publish original science and to form national and international networks.

science on stage, Prague
science on stage, Prague

Next to me is another UK award winner, Emma Crisell. Her primary school project on Food for the 21st Century - Making a Difference is absolutely wonderful combining gardening, ecology, hydroponics, soil science and food waste. I was really struck by her demonstration of soil loss between planted and bare soil.


6/3/2022 - Displaying Projects at European Science Teaching Festival

War permitting, I will be displaying the Infrasound and Aurora Monitoring Projects at the 2022 'Science on Stage Festival' SONS_2022 in Prague at the end of this month as part of the delegation kindly picked by the UK's ASE.

science on stage, Prague


30/1/2022 - Fortran vs Python

One of my sons has been coding a prime number generator using the ancient Sieve of Eratosthenes algorithm in python. This and conversations about programming languages led me to a speed-test of this numerically intensive task in python vs. Fortran. Specifically python3.9+numpy, gfortran11, nVidia's nvFortran, and Intel Fortran.

A program was developed first in Fortran, then translated to python attempting to maintain the same data-types and loop methodology,- download. The timings exclude disc writes of results to focus exclusively on the computation time. No significant attempt was made to optimise the algorithm.

Code was run on a Linux-64 system with a quad core i5 processor at 3.4 GHz with 8Gb memory. Timings shown are seconds to determine the approx 50 million primes in the range 2 --> 109.

Optimisation gFortran-11 nvFortran-21.7 Ifort-2021.5
-O0 13.5s 14.8s 15.2s
-O1 12.0s 13.4s 14.7s
-O2 11.9s 12.0s 12.0s
-O3 11.8s 12.0s 12.0s

python3.9 + numpy
not pre-compiled 509s
pre-compiled 510s

Timings are the average of 3 runs.

I may try and see if GPU offloading with nvfortran and OpenAcc has any effect.

For a sensible considered piece see Dan Elton's Why physicists still use Fortran.


17/1/2022 - Tonga Volcanic Eruption

Nathan has performed a detailed analysis of the Infrasound signals which we believe originated at Tonga. His report may be be seen (here)

Tonga Eruption - Infrasound


15/1/2022 - Tonga Volcanic Eruption - possible Infrasound Detection

We have spotted an unusually large, peculiar Infrasound pulse ~19:45 - 20:45 UTC which may be the subsea volcanic eruption near Tonga today. Still processing but given the approx 13 hour travel times this appears to correlate. Remarkable - see Infrasound project page.

Infrasound pulse detected by two different sensor rigs corresponding to ~13hr travel time Tonga to UK.

Tonga Eruption - Infrasound
Tonga Eruption


3/1/2022 - Fun in LaTeX

Aside from decorating and enjoying time wi t'family I have been working on our 'Learning physics through Coding' course. For each program we intend having background notes and additional exercises for the keener souls. Rather than simply hammering together a host of mismatched pictures found elesewhere we have been cooking them up in LaTeX tikzpicture package- which is nice though time-consuming.

I am trying distill some 25+ years experience in teaching A-level physics into this course.
Physics of FreeFall
As an example the start of the freefall and fluid drag background notes may be of interest (link)