Each sport had very different requirements, even between water sports they don't translate across.

My parent got a concussion surfing, was wearing a kayaking helmet because that's what he has.

The kayak helmet is thicker than a surf helmet and contains more buoyancy.

When his head it the water it slowed down to quickly because the helmet couldn't penetrate fast enough.

Concussion was fairly serious and is still in recovery 4 years later.

And climbing also has different helmets.

BMX racing and downhill MTB helmets are full face and DOT/SNELL approved

The proof is in looking at the thing. Bike helmets offer a much reduced rear of head coverage. Test requirements such as what you mention just cover testing the materials for impact durability, not the impact locations.

The Mohawk might provide a lot of cushion actually ( if they land upside down that is )

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....so oxygen bonds to carbon and releases energy and co2. We took oxygen, added carbon that was stored in physical matter, and released it as co2. So oxygen was removed, bonded with carbon, and released back into the atmosphere this time with added carbon.

So the net amount of oxygen atoms remains the same but we've now added carbon.

The carbon is "stuff". We've taken away no net oxygen atoms and we've added carbon.

You understand that 1-1+1+2 is the same as 1+2 right? Am I assuming correctly that this is at least something you get? Do I need to slow down?

Thanks reddit...so that's why my daughter has 5 different helmets. 1. Hockey, 2, Bike, 3. Skateboard, 4. Equestrian, 5. Ski

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Where are you supposing we source most of that O2 in CO2?

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That is impossible lol. We didn't "add stuff without taking away stuff".

If you think your only concern when skiing (or snowboarding) is fluffy snow, you either never skied or only skied high-end western US, European alpine, or some sort of 'exotic' mountain, all during prime conditions. Ice is a mainstay of pretty much any high-traffic mountain that isn't wide-open (such as all mountains in the eastern US, where you are almost exclusively regulated to established trails). Trees, rocks, and ski lift structures are also significant concerns on many mountains, as well. Some mountains even have condos right alongside some trails, meaning if you lose control, you could end up hitting a building or someone's vehicle.

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It's likely because the same environmental and lifestyle factors that contribute to cancer in humans can also affect animals. Additionally, some animals may be more susceptible to certain types of cancer due to their genetics.

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Motorcycle helmets are relatively big. Any worth buying will cover your entire head, including your face and eyes. The good ones will even extend down and squeeze your neck to create a good seal. This is good when riding a motorcycle because it makes for a quieter helmet. But for sports this means that your head is trapped in this almost air-tight hot box. Of course this affects motorcycle racers as well, but they've got the benefit of > 100 km/h winds entering the air channels and cooling them. Hockey players don't.

Motorcycle helmets are also considered one-and-done deals. (although this is heavily debated within the community) They've got a great, thick layer of impact absorbing material, but once that material has been hit, it loses its effectiveness.

TLDR: motorcycle helmets are bulky, heavy, and are designed to cover the user in a way that's detrimental to playing hockey. Playing a physical sport in one would be horrible. And their materials may not be suited for the use.

...what? were you under the impression clouds are just big fluffy white pieces of coal?

It's also worth mentioning that manufacturing quaaludes was chemically complicated and required some very specific base ingredients, meaning it wasn't cheap or easy to produce illegally, and when it was withdrawn from the market, the manufacturers of those key base ingredients stopped production as well, meaning it simply wasn't possible to make anymore. (unlike, say... how meth works...)

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well that's not how combustion works