25 things we learned by running a radical citizen science project about nappies (as you do)

At the end of a project, you usually put weeks or even months of effort into evaluating it and writing an evaluation report. Then about three people read your report.

Which is a shame, because if you’ve been honest, there’s stuff in there that might be useful to other people. So I thought I’d write a Buzzfeed-style listicle of things we learned doing this project, in the hope that more than three people read it and can learn from our many mistakes. Nappy Science Gang, making mistakes so you don’t have to…

Some of this is project evaluation findings type stuff, and some of this is just interesting factoids we found out. So it’s kind of a cross between reading an evaluation report and making stilted smalltalk with me at a party. Sounds fun, huh?

I should give you a bit of background before we start, or this list won’t make a lot of sense. Nappy Science Gang was an extreme citizen science project, where mums who use reusable nappies got together and came up with questions they wanted answers to, then designed and ran their own experiments to answer those questions. Mostly those questions were about cleaning nappies. Because if you re-use something, and its job is to catch poo and wee, then you think about cleaning a lot. We also talked to lots of scientists and found out loads of other stuff about babies, washing and science along the way.

Nappy Science Gang was funded by the Wellcome Trust and the Royal Society of Chemistry.

1. One of the first things we found out is that there is a special term, ‘socially clean’, for how clean we normally get normal things. Things that are socially clean aren’t really CLEAN clean. They still have loads of bacteria on them, for example. They just don’t smell or have stains on. The NHS washes laundry in a special process where they get heated to 74°C for ten minutes, to get rid of microbes. You can’t do that at home. Your clean laundry is just socially clean, not really clean. Your clothes all have bacteria on. I have tried to explain this to my Mum but she is having none of it.

2. Tea towel bacteria are worse than nappy bacteria. One of our members had a science background and had done her own experiments with different detergents to see how much bacteria was left on nappies after she’d washed them. She also washed some tea towels as a control. She found that the tea towels (unlike nappies) had bacteria on that were still alive after washing at 90°C. Euch. Never touch a tea towel.

3. The enzymes in biological washing powder still work at 40°C and even 60°C. Because they originally come from bacteria that live in geothermal vents.

4. Incidentally, there is no evidence that the enzymes in biological washing powders cause skin irritation. Although many people in the UK and Ireland believe they do, and buy non-bio because of it. Most other countries don’t even have ‘non-bio’ powder, and the people there don’t all get irritated skin. A scientific review paper concluded that detergents with enzymes in are no more likely to cause skin irritation than ones without. It’s actually the perfumes in detergents that are most likely to irritate your skin. They are in both bio and non-bio products, apart from some ‘sensitive skin’ type specialist detergents, which in the UK have no perfumes and also no enzymes. Bio is generally better at cleaning (because they put the enzymes in there for a reason), so there is a real gap in the UK market for a bio powder with no perfumes in.

5. We got the NHS to change their advice, which we thought would be impossible, but actually it really wasn’t that hard. They used to recommend washing baby items in non-bio. We asked them what evidence this advice was based on. They investigated. Professor Hywel Williams, professor of Dermato-Epidemiology and co-director of the Centre of Evidence-Based Dermatology at the University of Nottingham, told them, “I know of no good evidence that supports avoidance of biological washing powders or fabric conditioners and use of non-bio instead.” They changed their advice.

6. Facebook won’t let you invite more than 500 people to an event. Which is a real pain when you have a group with almost 2,000 people in and weekly events you want to invite people to. We ended up inviting different letters of the alphabet each time and asking people to let their friends in the group know about it. If anyone finds a better way round this, then please let me know.

7. Most babies don’t go to bed when the books say. At first we had our online Q+As with experts at 8pm, and no-one came. We asked in the group why people weren’t coming and everyone said, ‘Because I’m still trying to get my bloody beloved children to sleep.’ New (or prospective) parents take note: All the books lie. We moved the chats to 9pm and got a lot more people logging in.

8. Toddler sleep is all about the melatonin, which is ruled by sunlight. Toddlers being awake til 11pm is totally normal in midsummer. Someone should warn you about this stuff before you get pregnant.

9. Scientists don’t really understand HOW children learn language. (Like, they know some stuff about it, but there’s a lot they don’t know). But we do know that babies are starting to learn language in the womb. They are born more familiar with the sounds of the language you speak. If you spend your pregnancy in another country, they’ll be learning that country’s language, as well as yours.

10. Parents of young children are more interested in sleep than anything else. This is probably not news to you if you have children. The write-up of our chat with Prof Helen Bell from the Parent-Infant Sleep Lab at Durham University was our most shared post.

11. They also care about bacteria on their teatowelssecond most popular chat was Chantelle Loevberg.

12. Nobody talks about nappies on Twitter. For example, Gnappies are one of the biggest brands of reusable nappies but they only have 2,300 followers on twitter.

13. In fact, nobody talks about babies on Twitter. But they do on Facebook. We posted all our blog posts on twitter and also in our Facebook group. For most of that time my twitter account had more followers than there were members in the group. But still we got over ten times as many clicks from Facebook as from twitter.

14. Some companies take a lax approach to evidence, and don’t take mums doing science seriously. Read and enjoy this car crash of a live chat with a representative from Eco Eggs.

15. By the way, we think Eco Eggs don’t work. Dear all companies, we had a baby, not a lobotomy. Don’t underestimate people just because they are mums. It just pisses us off. And you don’t want a bunch of pissed off mums on your hands.

16. Problems you didn’t expect to be dealing with in your day job #327: It’s quite hard to send unidentified white powder through the post. One of our experiments involved us sending several sachets of mystery detergents to a load of volunteers. (They used them on their nappies and then rated the results and also swabbed their nappies and sent them to a microbiology lab.) We had a lot of trouble with this. We decided to check in advance as we didn’t want the parcel not arriving. The Royal Mail said we could only send white powder through the post if it was in its packaging and with a COSHH sheet listing all the ingredients. Which would kind of mess up the ‘blind testing’. Fortunately we found a courier service who were happy to take the parcels, once they had a letter from the Wellcome Trust saying it was for an experiment. The Wellcome Trust would like me to stress they are very selective about who they write letters for.


This is us doing legitimate citizen science, honest.

This is us doing legitimate citizen science, honest.

17. It’s not impossible to make projects extremely family-friendly. As it happened – perhaps because of the subject matter, perhaps because the job was short hours with flexible working – at the start of the project, all three staff members were mothers with small children. Our first team-meeting on skype, all three of us were breastfeeding at once at one point, and it was no biggie. About 40 people applied for the job of assistant on this project, at £8/hour. Nearly all mums of small children. Half of them had PhDs and most of them were wildly over-qualified. If more employers made the effort to be truly family-friendly, then maybe there wouldn’t be so many highly capable women, desperate for some interesting work that they could fit around their family commitments.

The table detritus from a family-friendly staff meeting in a cafe

The table detritus from a family-friendly staff meeting in a cafe

Our youngest team members exploring Manchester Museum after the meeting. As you'll know if you have any, toddlers are very difficult to photograph, as they move so quickly.

Our youngest team members exploring Manchester Museum after the meeting. As you’ll know if you have any, toddlers are very difficult to photograph, as they move so quickly.

18. Road-test your experiments. Even if you think you don’t have time to. ESPECIALLY if you think you don’t have time to. We found in ours that some of the instructions were ambiguous, so some people were asking lots of questions to clarify – which took up a lot of staff time, answering the same questions over and over again. And also, some people didn’t ask but interpreted them differently, and so some of the data was unusable. We were running late, so we thought we didn’t have time to pilot all the experiments. But actually, it cost us more time in the long run NOT to do a road test. Like I said at the start, Nappy Science Gang, making loads of mistakes so you don’t have to.

19. Ditto, get crucial things checked by more than one person. There was a misunderstanding about how the packs should be packed up, which meant that one part of the experiment was not ‘blind’ when it should have been. We were rushing and thought we were doing everything as efficiently as possible. But actually, some ‘redundancy’ with things being double checked by different people would have been better.

20. The Science Museum in London are lovely. Although it was mainly an online project, where all the organising was done in a facebook group, we wanted to have an event in the real world where we announced all the results, and got people together to talk about them and about the project. I contacted the Science Museum to say we were thinking of having it there, and could we hire a room or something. They lent us a room for free, gave us lots of advice on what to do in the museum, and one of their education staff came to meet us and sorted out all our problems. If you are a community type group doing an informal education project, I recommend them.

21. If you’re getting a well-known supermarket chain to deliver a load of food to the Science Museum, call them beforehand and clarify exactly where they should take it to. We thought this would be the most straightforward way of getting sandwiches and snacks for our get-together. We gave them the name of the member of staff who was looking after us. We thought they’d go to the delivery entrance and ask for said member of staff. The security guard could then radio him. They didn’t do this. They drove to the main entrance, waited a bit, tried to call me, and then drove away again with all our food.

22. There is no phone reception in the basement floor of the Science Museum. See point 21.

23. Some nappies have a strange exoskeleton of a mineral called hydroxyl apatite, which nobody had predicted. We got some persistently smelly nappies tested in a lab. According to nappy world mythology, nappies like this probably have ‘detergent buildup’. Another popular theory was that they’d have a buildup of oils from things like nappy rash cream. In fact, of the five nappies tested, NONE had significant detergent content. None had significant oil or fat content. They did all have loads of bacteria in them. And two out of the five had an exoskeleton of hydroxyl apatite, surrounding all the fibres. To find this out, the lab heated the sample to 600°C for 16 hours, which basically burnt away all organic matter and left a residue of inorganic ‘ash’. They they tested the ash and found it was made of hydroxyl apatite (a form of calcium phosphate) which is the main component of bones and teeth. Two of the tested nappies had just over 20% w/w of this mineral. One of our science advisors said that a normal ash value would be 1-2%. 3-4% would be high. He’d never heard of an ash value over 20% before. So we found out something pretty interesting.


A photo of the hydroxylapatite exoskeleton on fibres of a viscose nappy


24. You think manufactured things will be all the same. But actually they vary loads. eg Brand new, unwashed, terry squares vary in weight by ~20%. We found this out the hard way. For one of our experiments we bought five identical sets of nappies and then washed four sets 100 times, each set at a different temperature. The fifth set were the control. We did lots of tests on them all at the end, to see what the effect of washing at different temperatures was. We didn’t bother doing these tests at the start with all the nappies, because we had the control set, eh? When we compared the weights of nappies at the end, to their equivalent in the control set, we realised we had a problem. The differences in weights were all over the place. We asked a friendly nappy retailer to weigh some of her brand new nappies for us. “Huge variations! I’ve got two sets of salter electronic scales (domestic ones) and they typically give a 2g variation. The heaviest terry was 137g and lightest was 120g all from the same pack! Prefolds ranged from 174g to 161g. Less variation in wraps but still 9g difference for Little Lambs and 3G for prorap.” We should have tested all the nappies before we started doing anything to them. I realise this makes us look like a bunch of idiot amateurs, but we are learning to be OK with that. Like I said, making mistakes so you don’t have to.

25. Designing experiments is hard! In our feedback survey we asked our volunteers, “Has this experience taught you anything about designing experiments?” The most common answer was that it’s really hard. “Yes, it’s harder than you think!” Mainly because isolating variables is difficult. “It’s extremely difficult to identify all the variables, let alone put in controls for them.” I asked some scientists, they told me that this is mainly what they have learnt about science too. So it looks like taking part in a user-led citizen science project can teach you a lot about science.

If you want to know more about what we learned, more formally, from running Nappy Science Gang:-

Nappy Science Gang eval report executive summary

Nappy Science Gang evaluation report (compressed)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s