The experiments

In 2015, Nappy Science Gang conducted experiments on detergent, temperature and strip washing and discovered a mineral exoskeleton in our nappies that no-one predicted. Apatite for Destruction is currently investigating that mineral, and soon Parenting Science Gang will begin.

Scroll down for more information on the experiments and our results so far.


Our current experiments: An apatite for Destruction

In the course of our investigations in 2015, we found some nappies with an ‘exoskeleton’ of hydroxyl apatite (a mineral found in bones and teeth). Two out of the five nappies had about 20% w/w of hydroxyl apatite in the fibres i.e. 20% of the weight of the dry nappy was made up of this mineral. Read more about the background to the project here.

So far Nappy Science Gang have come up with a list of hypothesis and voted for their favourite. The top 3 hypothesis that we intend to investigate further are:

1. The calcium in the hydroxyl apatite is from hard water.

2. A nappy with HA will contain more live bacteria after washing than one with no HA under the same conditions.

3. Insufficient detergent makes hydroxyl apatite growth more likely.

We’d love you all to get involved in the discussions  (which you can do by joining the facebook group), and get your thinking caps on about what the Nappy Science Gang should research next!


Our 2015 experiment results

In 2015, the volunteers spent many months washing, swabbing and testing.
We now have some answers (though perhaps even more questions!) to our questions which we hope will be of use to the rest of the reusable nappy community.

Each of the experimental protocols have been updated with any changes that happened as we went along (temperature, detergent, stripwashing) and you can see the full results write ups here:

You can also see the responses of many of the gang to the grand results reveal in this chat write up.

How we came up with our 2015 experiment questions

After a discussion that lasted several weeks, with inputs from dozens of members and an official vote open to all members, the three “winning” questions that we researched were:

  • What’s the best thing to wash cloth nappies with (Bio detergent /non-bio detergent / liquid / powder/ eco eggs/ soapnuts)?
  • Is ‘strip-washing’ cloth nappies necessary? If so, what is the best method? (It’s commonly said that detergent build-up in nappies can cause you problems, so you need to ‘strip-wash’ periodically. Opinions differ on the best way of doing this. I have come across no scientific evidence that detergent build-up happens, or what the best method of strip-washing would be.)
  • What is the optimum temperature at which to wash cloth nappies?

These were referred to these as the Detergent, Strip-washing and Temperature questions.

Next, it was time to define and clarify what the group wanted to find out and come up with an experimental design to help us find an answer to these three questions. Since everything we do is though Facebook and in order to best focus on each question, we thought it would be a good idea to form three “working groups” for each questions, made up of the people that felt like they could invest more time into the design of the experiments. So we opened three further Facebook groups, each one dedicated to one of the three questions, and left it open to the group to choose what they wanted to work on (these are open groups and anyone can access them through these links: Detergent group,Temperature group, Strip-washing group).

Each group, made up of about 20 members, then spent several months discussing the experimental design and tweaking until everyone (including our science advisors!) felt happy and satisfied with the result. Follow these links to read the protocols of our three experiments!

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