© Science-y Hair Blog 2
The idea behind the float test follows this line of thinking: If hair is porous, it takes on more water than if it is not porous. Therefore, porous hair might sink because it takes on water and becomes heavy. That is - the weight of the water the hair is absorbing overwhelms the power of surface tension (between water molecules) that keeps the hair suspended on top of the water.
And in a sense this is not wrong but it is incomplete. But there are too many other variables in play to make this an accurate assessment of how porous your hair is by simply grabbing some hair and dropping it in a glass. Your experiment needs to be designed with far more care than you might think to get anything close to an accurate result. Given time and enough dunking - all hair will sink in water and stay sunk.© Science-y Hair Blog 2015
I used some hairs which are low porosity, porous, kinking and porous and mixed porosity (lower near the roots, porous at the ends). I tested the hairs when clean (no products), with conditioner added, with coconut oil added and with hair gel added (homemade flaxseed gel) because these additions can change the floating behavior of hair.© Science-y Hair Blog 2015
In most cases I put some hair on the water's surface and also dunked another of the same hair because some people dunk their hair (push it under the water) for the float test and it tends to give a different result, at least at first. Captions are below each chart. Click photos that follow to enlarge.© Science-y Hair Blog 2015
Time | Untreated | Oil (All dunked) | Conditioner | Hair gel |
Start | Floating, Dunked: Sinking | Sinks | Floating, Dunked: Sinking | Floating, Dunked: Sinking |
5 minutes | Floating, Dunked: Sinking | Floating | No change | Floating, Dunked: Partly floating |
10 minutes | Floating, Dunked: Sinking | Floating | Nearly all floating, dunked and un-dunked | Partly floating, dunked and un-dunked |
Porous, coily/curly (Type 4) hair which has been lightened (highlighted). When untreated, it did partly sink over time. But at least half of the hair was on the surface. With oil, it initially sank when dunked (all hairs were dunked in this case), but then floated as the coconut oil repelled water. With conditioner, the un-dunked hair floated until the end of the test when it was partly sinking but the dunked hair sank initially, then floated as the weight and specific gravity of the hair vs. water and the waterproofing of conditioner got the better of it. Hair gel in this case was similar to un-treated hair - though hair gel can make hair more water-attracting.
Time | Untreated | Oil | Conditioner | Hair gel |
Start | Floating | Floating, Dunked: Floating | Floating, Dunked: Sinking | Floating, Dunked: Sinking |
5 minutes | Floating | Floating, Dunked: Floating | Partly floating, dunked and un-dunked | Partly floating, dunked and un-dunked |
10 minutes | Floating | Same as at 5 minutes. | Same as at 5 minutes. | Same as at 5 minutes |
Mixed porosity hair (lower porosity at roots, porous at ends), loose curls with kinking. The untreated hairs all floated (none were dunked). The oiled hairs also floated. With conditioner, the wet-ability of the conditioner encouraged sinking, whether the hair was dunked or not. With hair gel, the wet-ability of the hair gel encouraged sinking.
Time | Untreated | Oil | Conditioner | Hair gel |
Start | Floating, Dunked: Partly sinking | Floating, Dunked: Floating | Floating, Dunked: sinking | Floating, Dunked: sinking |
5 minutes | Floating, Dunked: Partly sinking | Floating, Dunked: Floating | Partly floating, dunked and un-dunked | Floating, Dunked: Partly floating |
10 minutes | Floating, Dunked: Partly sinking | Floating, Dunked: Floating | Floating, Dunked: Partly floating | Floating, Dunked: Partly floating |
Low Porosity, coily (Type 4), kinking hair. This hair floated as expected when untreated and simply placed on top of the water - but it seems the shape of the hair pulled it down when dunked. It floated when oiled both dunked and un-dunked. Conditioner's wet-ability encouraged some sinking with time, as did hair gel.
Time | Untreated | Oil (All dunked) | Conditioner | Hair gel |
Start | Floating, Dunked: Partly floating | Floating | Floating, Dunked: sinking | Floating, Dunked: sinking |
5 minutes | Same as at start | Floating | Floating, Dunked: partly floating | Floating, Dunked: partly floating |
10 minutes | Same as at 5 minutes | Floating | Floating, Dunked: mostly sinking | Floating, Dunked: partly floating |
Porous, wavy hair, which has been lightened (highlighted).
The porosity of this hair encourages sinking when the hair was dunked. The hairs floated when oiled but conditioner's and hair gel's wet-ability encouraged sinking in the dunked hairs.
Comments:
Do you see any trends? © Science-y Hair Blog 2015
- Porous hair does indeed tend to sink somewhat reliably: 1) if the hair is clean - no products 2) over time, 3) if the hair is dunked under water first.
- Conditioner and hair gel on hair tend to encourage hair to sink if it has been dunked under water first - but it may float after a little while.
- The curl of hair or lack of curl or for that matter if you have hairs touching other hairs, may change the result, especially if you dunk hairs.
- Oiled hair tends to float - especially coconut oil.
- Dunked hairs vs. hair placed on the surface may produce a different result. And that result may change if you leave the hair for a few minutes. As you can see from the charts - whether or not a hair that sinks at first may float later on is not predictable, so I don't want to encourage you to try to predict a result based on whether it sinks and then floats. That's not accuracy.
Can you get an accurate result with the float test?
I am inclined to say no. If your hair is very porous like the porous hairs I selected and if it is very clean, then you might get a "porous" result. But if there is oil or conditioner or hair gel on your hair, or if it is just a little bit porous - you will not get an accurate result.
If your clean hair is low porosity at the roots and normal or porous near the ends, your hair will probably float, or sink partly - but if it does sink - is that because you dunked it, because there was some conditioner residue, because it came into contact with the side of the container? What other forces are acting on the hair? How porous is it really? More information is needed!
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So how do you test porosity? This post goes into depth. In general, lower porosity hair doesn't have damage. It also doesn't dehydrate easily - and that means it doesn't get dry on the inside and brittle. Lower porosity hair doesn't soak up a lot of oil and conditioner. But sometimes hair won't "soak up" those things because you've used henna, or because your hair is coarse (wide) and not very flexible (lots of inner support). Lower porosity hair doesn't tend to "take" hair dye or permanent waves or chemical relaxing easily. Normal porosity takes hair dye normally and porous hair takes hair dye very quickly. If your hair is generally very tolerant of just about everything, it's probably low to normal porosity. Most hair is more porous on the ends than near the roots. If your hair always seems to dry out easily and get brittle and break, it's more likely to be porous. If your hair is dyed or highlighted, it's more likely to be porous (but some hair will resist becoming porous with dye and bleach). If you spend a lot of time in the sun or swimming, your hair is probably porous - though it may or may not be as "dry" as you might expect porous hair to be.© Science-y Hair Blog 2015
Powers of observation
Of all the tools and products for hair, your eyes, hands, ears and mind are the most important. If oil and conditioner just sit on top of your hair, if you've never dyed it nor handled it especially roughly, it's probably lower or normal porosity. If your hair doesn't soak up loads of oil and conditioner, but can tolerate whatever a normal amount is for your hair length and thickness and curl pattern without getting greasy immediately and sometimes gets a little dry or lighter-colored, frizzy or flyaway or the ends start to look light (or invisible) - you're probably lower porosity at the roots, normal in the middle and more porous on the ends. If your hair soaks up lots of oil and conditioner and never seems greasy or weighed down and tends to be dry and brittle and always breaking - higher porosity.
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You decide how to treat your hair based on your baseline observations and how it responds to what you do to it. This post has recommendations for keeping lower porosity hair or hair that is difficult to moisturize feeling good. This post is about hair that is low/normal/porous and porous hair can use protein (if it's not coarse) and oil pre-wash treatments and deep conditioning to your heart's content. If you use a heavy-handed oil application and see a glimmer of improvement, but you needed to wash your hair 3 times to de-grease, don't swear off oils. Just use less. Maybe a lot less. Observe, make a plan, experiment, observe again, adjust as needed.
Science-y Hair Blog 2015
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Mixed porosity, curly and kinking hair, untreated. Still floating after 10 minutes. |
Science-y Hair Blog 2015
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Make the float test more accurate:
- Start with clean hair - swish it around in some water with a drop of detergent if your hair has any products (including oils and leave-in conditioner) on it, then rinse and let it dry before testing.
- Make sure the hair will not come in contact with the edge of the container the water is in.
- Dunk the hairs quickly (and completely) under the surface of the water to break the surface tension.
- If your hair has chemically-treated ends and un-treated roots of significant length, cut the hair in half and test those areas separately.
- Instead of using individual hairs, tie 15-20 hairs together (with a hair if you can) because individual hairs have very little weight - a greater mass of hair can take on more water if it's porous for a more obvious result.
Interpret your result (if following the instructions above):
- Hairs float at 5 and 10 minutes: Low porosity or low-normal porosity. Henna may give a low porosity result. Or may also be lower porosity roots and more-porous ends. Re-test the ends and roots separately!
- Hair partly floating, partly sinking: Possibly more-porous ends than roots if just one end is sinking, or porous hair if half or 2/3 of the hair seems to want to sink. Re-test the ends and roots separately!
- Hair partly sinking or seems to be just under the surface at 10 minutes: Porous
©Science-y Hair Blog 2015
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