Olivia: If you've ever gone surfing, diving, or even just swimming in the ocean, you may have worn a wetsuit before. But if our regular clothes get drenched we usually end up cold and shivering. So how does this skin-tight sopping wet onesie keep us warm? Well, wetsuits actually use a layer of water along with other layers of material, to trap your body heat. It all works because of thermodynamics.

Your body likes to be a toasty 37 degrees Celsius, which is typically warmer than the air or water around you. If two things have different temperatures, that means their atoms and molecules are bumping around at different speeds, with different amounts of kinetic energy. And heat energy gets spontaneously transferred from warm things which have more energy, to cool things which have less energy. So your body particles are constantly bumping into nearby air or water particles and transferring energy through a process called heat conduction.

Because liquid water molecules are more densely packed than air molecules, water is better at conducting heat than air. That means that cold ocean water will suck heat away from your body faster than cold air, which can get dangerous.

Enter the wetsuit. Wetsuits are designed to stop heat from escaping, also known as insulation. And they're made of layers upon layers of materials. The outer layer is tough and somewhat water-resistant, to keep most of the cold water out. Then comes a layer made out of neoprene, a rubber foam with lots of tiny nitrogen bubbles trapped inside.

These pockets of gas don’t conduct heat as easily as water does, so this layer is really important to keep your body warm. After that, some wetsuits have a layer of heat-reflecting metal, like titanium or copper. And closest to our skin is actually a thin layer of water, which is how wetsuits get their name.

See, wetsuits are designed to let in some water and trap it with all those insulating layers. So your body heats that water up because of conduction, and then the warm water helps you keep warm. Unfortunately, poorly-fitting or badly-designed wetsuits don’t trap this water layer very well, and might let too much cold water in.

Scientists are still trying to improve neoprene wetsuit technology. One team has even been inspired by water-dwelling mammals, like beavers.

Beaver fur naturally traps air bubbles, to create a gas barrier and prevent water from touching their skin and conducting heat. So these researchers are designing a fur-like rubber material, experimenting with the density and length of the hairs to trap air most efficiently. Who knows, in the future you might just spot a surfer sporting the latest animal-inspired wetsuit fashion!

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