It may be dangerously cold in the American Midwest, but that hasn't stopped people venturing out to see how freezing temperatures can affect everything from bubbles to urine.

Polar vortex exeperiments in the US (pictures: Youtube)

Parts of the United States have recorded temperatures lower than those in the Arctic, and even on Mars, as a blast of air from the polar vortex spreads south across the US.

In this life-threatening weather, frostbite can set in within minutes, and authorities have been forced to open overflow accomodation for thousands of people seeking to escape the cold.

What is the polar vortex? Weather Presenter Liam Dutton explains

However, some people have put a brave face on the polar vortex - posting videos on YouTube as they experiment in the arctic conditions. Channel 4 News lists our top six below.

Yellow snow

One young "scientist" in Minnesota risked life and one particularly cherished "limb" to see what happens when you urinate in -17F (-27C). The results, which can be seen in the video below, are a departure from the traditional experiment of throwing hot water into the air to see it instantly freeze.

If very hot water is thrown into the air in freezing conditions, because it is so close to boiling, it breaks into tiny droplets that freeze - creating the effect of frozen steam.

Warning: the below video contains some language viewers may find offensive.

Forever snowing bubbles

One woman and her mother used the cold weather in Michigan to freeze soap bubbles. In temperatures, including windchill, of -25F (-32C), the bubbles can be picked up off the ground and even squeezed.

Ice breaker

A man in Iowa posted a video to Vine showing what happens when you jump on a wet trampoline after it has been left in temperatures of -21F (-29C). The video, picked up by a local news station, shows the young man jumping from a stepladder to break ice.

Frostiest gun in the Midwest

The classic experiment that has been used on US television to show how cold it is has been to throw a glass of hot water into the air, but one man in Rochester, Minnesota, gave the experiment a twist.

Using a watergun filled with hot water, he created a "frost-thrower" in temperatures reported to be as low as -60F (-51C) including windchill.

Cool clothes

Stephen Clark, an anchor from 7 Action News, used a T-shirt to show how cold it was in Southfield, Michigan. Mr Clark said it took the wet T-shirt two minutes to freeze solid, and joked that when the item of clothing fell on him it "kinda hurt".

He said the test was proof that you "really need to bundle up out there", though presumably not if your clothes are wet.

Frostbite

When the sun comes out in the UK, one news cliche is to show how hot it is by cooking an egg on a car bonnet. In International Falls, Minnesota, a man turned the cliche on its head by showing how an egg freezes in five minutes on a metal pan.

The point of the video, Matt Sampson of The Weather Channel said, was to show how dangerous metal in such cold temperatures can be to human skin.