About this blog
July 2019
My name is Michael de Podesta and from April 2000 until April 2020, I was a scientist at the UK’s National Physical Laboratory (NPL). Prior to that I was lecturer in Physics at Birkbeck College and University College London.
Protons for Breakfast?
This blog stems from a course called Protons for Breakfast that I ran at NPL from 2004 until 2014. It aimed to help people make sense of some of the science they encounter in everyday life. The course generally entertained, amused and educated but its primary aim was to empower.
People are generally familiar with many parts of the body of scientific knowledge, but often they do not understand the context of their own knowledge, or how one thing they know relates to another thing they know. Protons for Breakfast was a ‘big picture’ course which aimed to make those connections.
The name of the course was based upon the fact that very roughly half the mass of what you eat for breakfast is protons! The name arose when someone – I’m not sure who – suggested it, and I liked the juxtaposition of the high-science concept of a proton, and the everyday experience of eating breakfast.
This blog
This blog is generally about things in the news which impinge on the topics we dealt with in the course. These include mobile phone safety, climate change and nuclear power. However, there are also personal comments and general proclamations about anything that captures my attention.
Since my professional retirement in May 2020, the blog has focussed largely on refurbishments to my house with the aim of lowering its carbon dioxide emissions.
All opinions expressed are my own and do not represent the views of any organisation. I also check my articles modestly thoroughly, but I can’t take responsibility for what you do after reading them! But if something is unclear or just wrong, please do let me know.
I started the blog in January 2008 and I moved it to WordPress in September 2009.
Me at work in 2002
Protons for Breakfast 
November 19, 2009 at 11:51 am |
Following on from last weeks topic; After playing tennis on artificial carpet courts we often get an electric shock when opening the gates of the courts, but if we use the end of the tennis racket to pull back the door we do not get a shock. Is this because the racket has some sort on insulating element.
I’m afraid I do have a VERY poor understanding of atoms etc as there is a total lack of science in my formal education.
Sorry this is so late in the week.
February 14, 2015 at 8:44 am |
Please let me know dates of next courses.
February 23, 2015 at 1:42 am |
Cathy, sorry for the delay in replying. There are no more courses.
All the best
Michael
August 31, 2020 at 12:10 pm |
Hi,
Understand you have retired from NPL but wondered if you could let me know your new email address? There is something I’d like to ask you. thanks
September 16, 2020 at 7:59 am |
Hello Michael….Sam from Malaysia here…..would love to re connect if possible. Do please send an email. I have some situations that i would like to discuss with you.
November 3, 2020 at 9:56 am |
Dear Michael, I am secretary of the Cardiff Scientific Society and we would love to invite you to give a public lecture as part of the Cardiff Science Festival in Feb half term 2021. Would you please get in touch if you would like to accept our invitation?
November 3, 2020 at 12:19 pm |
Thank you for your kind invitation: I will send you a message off-line.
December 21, 2020 at 4:32 pm |
Dear Michael,
Remember Varenna 2016 and 2019? I’d like to get in touch with you, would you mind sending me an e-mail?
Thanks and kind regards,
February 2, 2021 at 3:47 pm |
“The Last Artifact” featuring Michael de Podesta made it to the final of the LabMeCrazy! Science Film Festival https://www.unav.edu/en/web/labmecrazy. Join directors Jaime Jacobsen and Ed Watkins for a lively chat during the Festival on Tuesday Feb 2nd at 19:30 CET on Youtube https://youtu.be/z3J2vMyVI_Y
May 20, 2021 at 9:46 am |
Dear Dr Podesta, I contacted you about your book last year and we have arranged it online for our 250 students via Koretext. I would like to ask you a question about the book but cannot find an email address. Best wishes Mike Gunn, University of Birmingham
j.m.f.gunn@bham.ac.uk
September 16, 2021 at 8:06 am |
The BBC program last night – The Last Artifact – redefining the Kilogram – missed out a important Newtonian principle – gravity
And did not explain to the public the difference between Weight and Mass – which confuses a lot of people.
Should we weigh something or measure it’s mass !
As gravity varies over the earth – that needed a comment in the program
September 16, 2021 at 8:51 am |
Indeed!
This aspect is widely misunderstood, most especially by physics teachers who try to tell students that weight should be measured in newtons!
The key here is that “Measurement is quantitative comparison of one thing against a standard”
A balance of any kind measures the force of gravity on one MASS against the force of gravity on a STANDARD MASS IN THE SAME PLACE .
The device is thus measuring mass by comparison against a standard.
In contrast – and perhaps this is the point you wanted to make – a Watt Balance/Kibble Balance compares the gravitational force (m x local g) against an electromagnetic force measured by a voltage and a current.
It this requires a local measurement of gravitational field strength which is a fascinating experiment in its own right – it varies from minute to minute and across the floor of the lab!
Anyway, I think the film makers just didn’t feel able to address this level of detail. Hey ho.
Best wishes
Michael
January 25, 2022 at 3:52 pm |
Dr de Podesta, I am shielding so cannot attend your prestation to Twickenham Friends of the Earth. I want us to install air to water heat pump for renewable energy. Could we know the contractor you used? We’d be so grateful, All the best, Sincerely, Judith
January 25, 2022 at 4:01 pm |
Judith,
We used a company called Enhabit. I’ll drop you a note by e-mail too.
Sustainable Bankside II, 25 Lavington Street, London, SE1 0NZ
T – 020 8380 8908
http://enhabit.uk.com
@Enhabitfeed
(I have removed your e-mail address from the post because bad people can snaffle them!)
Michael
October 11, 2022 at 11:06 am |
Dear Michael
My 12-year-old son has great admiration for you and your work at NPL, especially the water rocket simulator and documentation you have compiled.
I see many requests for your contact detail and do not know if you can/would share them for advice and for him to send you his research report. He performed actual tests with water rockets and used your simulator as validation – he found interesting results.
It will be great if you are willing to share your detail.
Best regards
Pieter Conradie
(father of Niel Conradie and a researcher myself at a University in South Africa)
October 11, 2022 at 11:21 am |
Pieter, thank you for your kind words.
You and Neil can write to me at house@depodesta.net and I will be sure to take a look at the report.
Best wishes
Michael
January 13, 2023 at 12:58 pm |
I’ve just signed up to PfB and found the artices on heat pumps very informative and educative. I’ll no doubt find the articles on solar and batteries equally useful as I get a chance to catch up on reading them.
I have been suspicious about the size of ASHP quoted for our house because my starting point has be our actual current gas consumption over the many years we have lived here. On a very simplistic basis if I can expect an ASHP to be 4 times more efficient than a gas boiler I expect my annual 16,000 kWh gas for heating to be reduced to around 4,000 kWh using electricity. So quotes for a 11.2 kW ASHP system I’ve had don’t make sense to me.
January 13, 2023 at 1:50 pm |
Gordon, Good Afternoon.
I am glad you have found the articles on Heat Pumps helpful.
I think you are quite right to be suspicious: many surveys significantly overestimate the size of heat pump required – often by a factor two or more.
Using my ‘Rule of thumb’ (Divide annual kWh of gas by 2900) I would guesstimate that you would need a 5.5 kW heat pump.
https://protonsforbreakfast.wordpress.com/2022/04/05/what-size-heat-pump-do-i-need-a-rule-of-thumb/
If you have data for the recent cold weather you can make an even more specific calculation. Or perhaps we will have some cold days coming up.
https://protonsforbreakfast.wordpress.com/2022/11/07/what-to-do-on-the-coldest-day-of-the-year/
All the best
Michael
February 1, 2023 at 1:08 pm |
Bizarrely this week I discovered you on You Tube as I have recently had an air source heat pump put in .
Coincidentally I live in Teddington! Not only that i happened to be in The Mason’s Arms last night and very much enjoyed your performance especially your song Pointless .
At some stage I would very much like to come and see your air source heat pump as I am a complete novice and learning slowly the workings . I live in Coleshill road
David
February 1, 2023 at 5:22 pm |
David, Good Evening.
Indeed, what a strange coincidence! Especially as I only heard about the Open Mike earlier in the day and it’s the first time I have sung outside the folk club! But I am glad you enjoyed the song.
Regarding a visit to the heat pump, sure. Drop me a line at house@depodesta.net and suggest a time or two during daylight. If it’s not convenient I will just suggest something different.
All the best, Michael
February 3, 2023 at 11:08 am |
Hello Michael Please can you contact me to discuss your MMSP system for your heat pump. Enhabit are no longer MCS certified and I can help to ensure you remain eligible for the scheme. Kaspar
February 3, 2023 at 12:08 pm |
Thank you 🙂
February 11, 2023 at 3:11 pm |
Michael, thank you for a very illuminating blog and showing that my obsessions are shared by at least one other.
I’ve been trying do do very similar analysis on my house heating performance with very poor success. I’ve tried to get some feedback on my methods with not much help coming back. Would you be interested in engaging on this? I wrote a post (link below) before realising quite how much heat we are losing in certain winds, & have since managed to compensate for an error in the ASHP output estimates too. It’s still not showing a great correlation though (R^2=0.68).
https://forum.buildhub.org.uk/topic/31284-has-anyone-tried-comparing-actual-ashp-performance-with-their-heat-loss-calcs/
I hope you’ll feel stimulated enough to look at my technique & discuss what I’m doing wrong or misunderstanding.
February 15, 2023 at 11:40 pm |
Hi Michael,
Here’s my author page:
https://www.nationalgeographic.co.uk/author/dominic-bliss
April 9, 2023 at 4:04 pm |
Hi Michael,
Thanks for the wisdom that you’ve kindly captured and shared in the htc spreadsheet. I’m trying to adapt it to my needs for where I live in Hamburg, Germany. I plumped for Manchester’s latitude but one thing that is missing for me is the consideration of underfloor heating. Our house doesn’t have *full fidelity* underfloor heating with individual control of the respective areas but the backflow of warm water from the radiators flows through the underfloor pipes/hoses. Any thoughts on a factor for that?
Other question would be a separate heatpump for warm water. I was thinking of installing this in the cellar (although I’m a little worried about how cold the air will get in the winter months). Separating out warm water from heating would allow us to phase the switch from gas to a heat pump whilst getting better overall efficiency system wide by being able to completely turn off heating during the summer months (we have a 10 kWp solar system with an 8kW battery installed).
Any thoughts?
Cheers
Gary
April 9, 2023 at 6:17 pm |
Gary, thank you for your kind words. But you ask tricky questions!
1. Hamburg is almost certainly colder than Manchester. I would suggest you look up the number of heating Degree Days for Hamburg at:
https://www.degreedays.net
The ‘Rule of Thumb’ is that if your internal temperature is 20 °C, you look up the heating degree days for 16.5 °C : these are labelled as HDD16.5 . Download (say) monthly data for the last 3 years – it’s free – and work out the number of HHD16.5s there are in a year. This will give you data for three winters.
In the spreadsheet I downloaded data for a variety of UK cities for different internal temperatures and I then interpolate to get the appropriate value of HDDs for whatever the user picks as their internal temperature.
2. I am working on the next revision of the spreadsheet which will include UFH. It’s tricky as there are many types, but a radiator constant of around 10 W/m^2/°C is probably about right. You can just type this number in the spreadsheet to see the effect. But you will need to reduce the flow temperature to a maximum of 30 °C.
3. Regarding a DHW-only heat pump, I just discussed that thais afternoon with a user by the name of WINTERGREEN at the end of this article
https://protonsforbreakfast.wordpress.com/2023/04/08/perfect-solar-days/
These heat pumps typically draw in air from outside using ducts and expel the chilled air outside too. There may be some practical advantages to having a separate DHW supply, but I think in energy terms the advantages are quite small.
Anyway: best wishes. If you need help with your heating degree days, drop me a line at house@depodesta.net
M
April 14, 2023 at 12:15 pm
Thanks for the reply. Luckily, when sizing for a heat pump, different approaches do in fact converge quite nicely. I’m still interested in the separate heat pump for water heating as it seems to a) work well b) allow me to completely turn off the “main” heat pump in the summer (thus avoiding stops and starts and c) I can phase the switchover from gas. Installers in Germany are struggling with managing installations as projects and I expect much better efficiency and packaging in the future.
Cheers
Gary
May 15, 2023 at 7:15 am |
I think you might be the guy to answer a question I’ve had about wind power for many years.
When a wind turbine turns, it removes energy from the wind as it passes through the turbine.
Therefore, is it not the case that we are changing the wind by adding all these wind turbines. Does this not mean that we will cause issues with the climate through this energy change that’s on a par or worse than our carbon issues with the greenhouse effect?
Would love to see a blog entry on this at some point. I’m sure you’re busy though.
Nigel Smith
May 15, 2023 at 8:51 am |
Nigel, I have added that topic to rather long list of blog topics. Hopefully it will will filter its way through to teh top soon.
But before I write the definitive version, yes, wind turbines do extract energy from the wind and slow it down. Each turbine leaves a ‘wind shadow’ for – very roughly – a few times the height of the wind turbine. But it’s a very small effect.
Firstly each turbine can only extract at most 59% of the energy in the swept area of its blades. In practice this is at best more like 50%. And of course there are big gaps between wind turbines in a farm which means that only perhaps 10% of the wind energy in the cross section of the wind farm is intercepted. And then there is the fact that the winds extend to about 10 km high, whereas our tallest turbines are only 0.3 km high. So overall, even in the grandest conceivable roll out of wind farms, only perhaps 0.1% of the wind energy would be harvested.
But remember that winds are driven by the Sun, and the Sunlight falling on Earth provides 10,000 times more energy than humans need. We only need to tap into 0.01% of the Sun’s energy to supply all our needs!
Best wishes
Michael