Are white helmets cooler?

[ExpatinIstanbul]

I did a test with a black Nolan next to a white Arai Tour-X. I left them out in the sun (32c) for two hours....the Nolan was very hot to the touch, the Arai barely warm.

On a trip to Marmaris from Istanbul, my wife wore her Nolan, I used a white Lazer open faced MX lid, hers was almost painful to touch, mine was again only barely warm.

Whether or not the lining dissipates any heat absorbed by the shell, I don't know. I do know that having used a black Schuberth when I first moved here, I'm bloody pleased I've now replaced it with white helmets. I most certainly notice a difference.

 

[bowser]

I did a test with a black Nolan next to a white Arai Tour-X. I left them out in the sun (32c) for two hours....the Nolan was very hot to the touch, the Arai barely warm.

On a trip to Marmaris from Istanbul, my wife wore her Nolan, I used a white Lazer open faced MX lid, hers was almost painful to touch, mine was again only barely warm.

Whether or not the lining dissipates any heat absorbed by the shell, I don't know. I do know that having used a black Schuberth when I first moved here, I'm bloody pleased I've now replaced it with white helmets. I most certainly notice a difference.

I dont wish to be a pain (ok I do) but if you touch the helmet and its hot to the touch it the heat it is radiating that you are feeling and not the heat being absorbed.
I think that is the problem and the misapprehension that people have, black feels hotter therefore it must be, however according to the info its not the case black absorbs no more than white. Tuareg wear black! also the fact that white reflects more than black is I think only in the visible spectrum and that is not heat the heat is in the IR spectrum and that is affected by the type of material not what colour it is.

 

[David Nimrod]

Somebody needs to put a thermo probe type thing into the lining, and repeat Expat's experiment...

 

[Fanum]

They must be cooler -

White - reflects heat

Black - absorbs heat

(Although I did get a 'U' for Physics O level)

Whether they are 'cool' though, is another question entirely

So why are polar bears white, and sub-Saharan persons 'non-white' ?

Black absorbs heat, but it also radiates it better....

The helmets I've been wearing in Morocco for the last 7 years have been black or metallic silver, and I never noticed any difference

 

[David Nimrod]

So why are polar bears white, and sub-Saharan persons 'non-white' ?

I've got a feeling you're about to tell us...

 

[Grey Beard]

I dont wish to be a pain (ok I do) but if you touch the helmet and its hot to the touch it the heat it is radiating that you are feeling and not the heat being absorbed.
I think that is the problem and the misapprehension that people have, black feels hotter therefore it must be, however according to the info its not the case black absorbs no more than white. Tuareg wear black! also the fact that white reflects more than black is I think only in the visible spectrum and that is not heat the heat is in the IR spectrum and that is affected by the type of material not what colour it is.

When you touch a hot object, the heat transfer to your hand is by conduction, not radiation, which what you are talking about in 'Black Bodies'.

Try walking barefoot on a beach with black sand or black specs in it, compared to a pure white sandy beach in a sunny hot climate and you will be under no illusions, which is hotter to the touch!

A black helmet surface temperature will be much hotter in the sun than a white helmet. The fact that it feels hot, means that it is at a higher temperature than your body temperature and therefore, the heat energy will flow from the hot outer surface of the helmet into the cooler inner surface of the helmet. Whether the helmet will in fact feel any warmer will depend on just how hot the outside is and the ventilation efficiency of the helmet, speed you are travelling, etc.

People in sunny areas have dark skins (pigmentation) to protect against the effect of the UV radiation in the strong sunlight, though generally they don't like going out in strong sunlight because it is hot, or because they, for cultural reasons, don't want to become any darker skinned than they are already (at least in the Jamaican population).

Grey Beard

 

[ExpatinIstanbul]

I dont wish to be a pain (ok I do) but if you touch the helmet and its hot to the touch it the heat it is radiating that you are feeling and not the heat being absorbed.
I think that is the problem and the misapprehension that people have, black feels hotter therefore it must be, however according to the info its not the case black absorbs no more than white. Tuareg wear black! also the fact that white reflects more than black is I think only in the visible spectrum and that is not heat the heat is in the IR spectrum and that is affected by the type of material not what colour it is.

Black absorbs light, which becomes heat. Apparantly.

http://www.newton.dep.anl.gov/askasci/phy00/phy00156.htm

Tuareg are hard bastards, although why they wear black crash helmets is beyond me.

 

[Micky]

FFS you're not going to be sunbathing in the feckin' thing are ya

 

[Schtum]

FFS you're not going to be sunbathing in the feckin' thing are ya

Well, actually..... it was 40 deg C for most of the 1200 miles across Indiana, Illinois, Missouri and Kansas earlier this month. I was glad of my vented jacket and trousers and my white Shoei Hornet with a dark tint Pinlock in a light tint visor. Up on pegs of the Pan at 85 mph on the freeway for quite a bit of the time, trying to keep cool and ease the pain in my arse....

 

[Micky]

Well, actually..... it was 40 deg C for most of the 1200 miles across Indiana, Illinois, Missouri and Kansas earlier this month. I was glad of my vented jacket and trousers and my white Shoei Hornet with a dark tint Pinlock in a light tint visor. Up on pegs of the Pan at 85 mph on the freeway for quite a bit of the time, trying to keep cool and ease the pain in my arse....

OK Mike ... it was nudging 50 degrees in Turkmenistan and the silver Schuberth wasn't a problem either

 

[Schtum]

OK Mike ... it was nudging 50 degrees in Turkmenistan and the silver Schuberth wasn't a problem either

Pah....I bet the humidity was higher in Kansas.....!

 

[jeff]

Huge difference in hot country.

 

[Loiq]

So why are polar bears white

Polar bears are not white....

the fur is white well actually it's clear, hollow...but polar bears are black skinned....

 

[Popell]

I dont wish to be a pain (ok I do) but if you touch the helmet and its hot to the touch it the heat it is radiating that you are feeling and not the heat being absorbed.
I think that is the problem and the misapprehension that people have, black feels hotter therefore it must be, however according to the info its not the case black absorbs no more than white. Tuareg wear black! also the fact that white reflects more than black is I think only in the visible spectrum and that is not heat the heat is in the IR spectrum and that is affected by the type of material not what colour it is.

By this reasoning, the black would actually be cooler The heat comes from somewhere! the black feels hot because it is just that, having absorbed more energy

I have had a few pints but am struggling with this conflict of logic that you lay before us

 

[JPB]

Polar bears are not white....

the fur is white well actually it's clear, hollow...but polar bears are black skinned....

having the appearence of white fur provides useful camouflage and helps them catch their prey, or at least it did before the ice cap started melting!

 

[Timolgra]

having the appearence of white fur provides useful camouflage and helps them catch their prey,

......