Porosity is tricky to define because of these three things:
1) Porosity is a physical condition that belongs to an individual hair - or a portion of a hair. It is the amount of surface area with porosities - gaps and holes through which water and other things can move.
2) Porosity is a behavior or your individual hairs and your hair as a whole - how quickly does water move through any porosities present.
3) We want to use porosity to determine what to do to our hair - but all the things we do can modify our hair's porosity-behavior or even mask actual porosity. For example, sun-damaged and therefore porous hair may feel different than bleach-damaged and therefore porous hair. Or hair which is easily weighed down or low-density (thin hair) may or may not be able tolerate lots of conditioner and heavy oil applications that we usually think porous hair needs. Different porous hair has different needs.
Why does porosity-behavior matter? Let's say you use a henna or cassia treatment on porous hair and it suddenly seems to be water-repellant. It doesn't seem to get wet and dries very quickly. That is a behavior of very non-porous hair. The same thing can occasionally happen with protein treatments or oil treatments, especially with coconut oil or butters.
Has that hennaed, cassia-ed or oiled hair truly become less porous? Yes and no. The porosities that were there before still are there. But the movement of water through those porosities has been delayed by the henna or cassia residue. The hair's behavior is less porous, but the hair still has porosities - it just takes a lot longer for water to move through them. With coconut oil and hair-penetrating oils, the oil repels the water, causing non-porous behavior in normal porosity to porous hair.
Experimental design
When we want to set up a test, one of the first things we have to consider is this: are there any ways this test can be biased? In other words - does anything in our hair's environment change the results of this test?
To do this, I'm taking hairs from one person. These hairs are low porosity on the top 1/3, normal porosity for most of the length and more porous towards the ends. No hair color, no henna, no cassia.
We have 4 "treatment groups."
- Hair which has nothing added (washed and dried with no conditioner or styling product)
- Hair which has coconut oil applied
- Hair which has leave-in conditioner applied
- Hair which has a little oil and flaxseed styling gel.
The water temperature is lukewarm - not warm enough to liquefy oils and not cold. I used a glass dish of water with a large surface area for this - which is actually also important to the results of the test because the hairs did not contact the sides which might override the surface tension of the water. More on that in another post.
I treated the hairs and placed them lightly on the water surface. Every single one floated immediately.
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| Click to enlarge! Black arrows point to hairs floating on the surface. These are all lighter colored hairs and even with the contrasting color background, the camera had a difficult time "seeing" the hairs on the water. |
I left the hairs for 2 minutes. Still floating. And still floating a minute later. I'm impatient, so I dunked them quickly.
After dunking: The hair with conditioner began to sink. About 1/3 of the hair's length ultimately sank. The rest remained on the surface of the water. Until I gave up after about 10 minutes.
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| Click to enlarge! Black arrows point to the place where the hair with conditioner on it is submerged (to the right of the arrows) vs. floating on the surface (to the left of the arrows). |
Simple conclusion for Part One: Lots of leave-in conditioner or conditioner-enriched styling products can encourage hair to sink that would normally float.
Now we are already asking ourselves - is this a good test if we have to control conditions carefully or we get a biased result? In science, that is okay. For example: You can't get accurate results from reactions you do in dirty test tubes. Those things that go into your experiment usually need to be controlled in one way or another. But if you just wanted an accurate result from your hair and you have leave-in conditioner or conditioning hair products in it - it's more likely to sink. Though it may not!
Conditioner is a 'wetting agent" so we could have predicted this result. If you need to get your hair wet in a hurry - put conditioner on it first. It will get wet more quickly. Did the conditioner act as a wetting agent here? Probably. It added weight - but not that much weight and the oiled hair also had additional weight and it did not sink.
Did the oil repel water and keep the hair floating? Apparently not. Because the hair which was washed and the hair with a little oil and hair gel also floated right along with the oiled hair.
Should I have left the hairs for 30 minutes? Overnight? I don't think that's going to improve the test. Anybody's hair will get waterlogged after that long in water.
Next time: Hairs of different widths, curl patterns and porosities. I'll be using darker-colored hairs and daylight - the pictures will be much better.
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