Testing bubble solutions, troubleshooting them and then coming to appropriate conclusions is more challenging than you might imagine. Because of the complex interactions between bubble juice, the wand and the environment, it is important not to draw conclusions prematurely. We have been excited about test results that seemed convincing only to find that other people had difficulty reproducing them.
Here are some quick guidelines:
- Never draw conclusions based on a single session! This can't be emphasized enough. People often report "breakthroughs" based on one or two sessions with a new mix -- only to realize later that particularly good (or bad) conditions were responsible for the result.
- Compare solutions in the same session! If you are evaluating/comparing two solutions, the evaluations must be done in the same session in order to eliminate the possibility that changing environmental factors are responsible for the differences.
- If you are evaluating/comparing two solutions, do not draw any conclusions until you have tested them on several occasions in the same session. One test session or two are not adequate.
- Do not draw any conclusions until you have tested against a known "benchmark" solution (see below) or solutions on more than one occasion.
- Do not have too much confidence in your conclusions unless someone else is able to reproduce your results. It is easy to fool ourselves wthh exciting but premature conclusions. Let the truth be your guide. If others cannot reproduce your result, see if you can figure out what is different in their attempts from yours.
- If at all possible, do some blind tests of solutions that you are comparing. Even the most careful tester can be influenced by their expectations.
- Try to make sure that your test setup is such that you can see the colors clearly. The colors of a bubble film tell you a lot about the state of the bubble film and how its thickness is changing. Ideally, you want to see the colors as clearly as the best ones in the article Evaluating Color.
Read the sections below for more thoughts about testing.
Evaluating bubble "juice" and soap bubbles can be tricky. Even under controlled conditions, there is a fair amount of performance variation. When you throw in real-world uncontrolled conditions, there is so much variation in performance from bubble to bubble that you need to be careful not to prematurely draw conclusions based on what may be normal random variation. Keep in mind that even if you do simple coin flips -- a simple system with only two possible outcomes -- you would be likely to think that your coin had a particular bias if you based it on a simple succession of 10 flips. With bubbles, there are so many factors involved that you need many sessions before you can make a fair assessment of a bubble mix. Make 20 bubbles in a row with the same solution and same equipment. You will likely see a fair amount of variation. If you repeat the process on a number of different days, you are likely to have some days where things work out very differently than others.
Atmospheric conditions (temperature, wind, humidity, suspended particulates such as dust, etc) can play as big a role as the bubble juice. Sometimes, there are invisible environmental factors that influence a session without our being aware of it. Many people have decided a juice was subpar because on a 60F day with 80% humidity, the juice did not perform well. But then, two days later the same juice works great. Things like unseen particles from somewhat distant construction or a smokestack or pollen blown from a tree on the next block can destroy your bubbles without your knowing it.
I recommend logging your sessions and when possible to video record them. I have been shocked at the number of times that I have taken notes in the field of my impressions only to review video and find out that my conclusions were not supported by the video. The same has happened to countless other bubblers.
When logging your sessions, make note of:
- time of day
- wand material
- wand size
- bubble size
When testing a solution, if you are not an expert, don't start by using giant loops. Loops with a top-string of about 32" (about 80cm) are a great size. They can create quite big bubbles as well as long tubes. They also work well in both calm and somewhat windy conditions. Larger size wands will only work in fairly calm conditions. Large size wands also tend to show much greater variance in bubble life than smaller wands. The statistical noise seems to get louder as bubbles get bigger.
When evaluating a bubble solution, you should keep your goals in mind as well as the atmospheric conditions. Some solutions are more sensitive to conditions than others. See the article Ideal Conditions to learn more about how conditions may impact your conclusions.
It is very useful to have a benchmark solution that you use as a point of comparison. It does not need to be the best possible solution. It should perform well-enough that it gets decent results in most conditions where one could reasonably expect to make bubbles.
It is essential that the benchmark solution be stable and reliable. For this reason, it is often a good idea to use a commercial product that is known to be consistent. Some people consider Uncle Bubble Ultra Concentrate as a good benchmark although it has the drawback of using your own water (which could conceivably introduce some variability). You could use bottled water to add a level of consistency.
I use my basic guar gum based juice as a benchmark as it has proven itself to be a good performer in a large variety of conditions with consistent performance. It is not necessarily the very best recipe that I know of, but I find it to be a good point of comparison. Guar gum powder seems quite stable in storage. So, guar gum (or HEC) based mixes have some advantages over PEO since PEO is well known to change over time.
Using a benchmark will help buffer you from drawing conclusions based on unrecognized environmental variations. Any time you test a solution, perform the same test on your benchmark solution and make notes about the absolute performance AND (more importantly) how it compared to the performance of your constant.
Don't ever draw conclusions about the relative merits of a solution until you have had a chance to try in a few sessions side-by-side with your benchmark. While your first session might be representative, it might not.
Considerations when using wick-based wands
When comparing solutions using wick-based wands (such as tri-strings, nets or wick-wrapped rigid hoops), it is best to have one fresh loop for each solution. Even if your wring out and/or rinse your loop, it can take a surprising number of dips to clear the old solution from the wick when moving to a new solution. This is especially true if you move from a less to a more dilute solution.
The more soap that there is in a solution, the more that it tends to be retained (disproportionate to the amount of water) by the wick. So, if you have no choice but to use the same wick, start with the most dilute solution. Disregard the first 5 or 6 dips after moving to a new solution. It can take even more dips, in some cases, to fully clear the old solution.
When cleaning test wicks, wring them out, rinse them then let them soak in a lot of water. Then repeat.
Is the bubble juice for creating huge outdoor bubbles with a string wand? Is it for blowing bubbles with a small wand or for use in a bubble machine? No one solution is ideal for all types of bubbles -- although some solutions at different dilutions can give pretty good results for a wide-range of bubbling.
See the Troubleshooting article for thoughts about troubleshooting solutions.