Kate the Chemist: Water is a freak substance. Here’s why.

Dr. Kate Biberdorf explains why boiling water makes it safer and how water molecules are unusual and cool.

DR. KATE BIBERDORF: When you boil water what you are doing is making sure that the temperature of your water is so hot, basically as hot as it possibly can be before all the hydrogen bonds break and the water itself goes from the liquid state to the gas state. And so when we're looking at water that happens at 100 degrees Celsius which is around 212 degrees Fahrenheit. When we do that we bring the thermal energy of the water up to a high temperature that any viruses or bacteria that are inside that water actually are killed if and only if you boil that water for at least five minutes. So the recommendation is five minutes. When I am boiling my water because we had an issue here in Austin about a year ago where we had to make sure we had very safe water. We had to protect it. When I boiled my water for that I boiled it for ten minutes just because I'm a little bit of a freak or I like to overkill things. But what you want to do is you're basically making sure that there's enough thermal energy inside that water that it makes sure that the viruses and the bacteria that are currently in there can no longer survive. And so it's about getting the temperature hot enough and keeping it there for a long enough period of time to make sure all those viruses and bacteria are killed.

Water is a freak and so it is one of my favorite molecules ever because it has these unique properties and we are surrounded by it constantly. We also are made of water. We have to drink water to survive. Some of us like to swim so we're always inside of water. So it's a really, really fun molecule to investigate. What's cool about water is it has these things called hydrogen bonds. And so what that means is it forms an intermolecular force between one water molecule and another water molecule. So the oxygen on one water molecule is partially negatively charged and so that oxygen is somewhat attracted to the partially positively charged hydrogens on another water molecule. So oxygen from this one, hydrogen from this one are attracted to each other. And so that certain thing is called a hydrogen bond and the distance or the length of the hydrogen bond or the distance between the molecules is what sets how much space those water molecules together occupy.
So a glass of water contains a ton of different water molecules and they all have different hydrogen bonds between them. So when you take a chunk of water like and put it in an ice cube tray and then you put it into your freezer we're going to see that the water actually expands. So water is super weird. This is not a normal thing but when it goes from the liquid state to the solid state the distance and the length of those hydrogen bonds actually increases. So water is actually more stable in the liquid state which his super rare. That's just uncommon. But it is what it is. That's what water does and we're around it all the time so there's your answer.

  • University of Texas professor and science entertainer Kate the Chemist joined Big Think to talk about water molecules and to answer two interesting and important questions: Why does boiling water make it safe to drink, and what happens to water when you boil or freeze it?
  • According to Kate, when water is heated to a certain temperature (100°C/ 212°F) the hydrogen bonds break and it goes from a liquid to a gas state. Boiling for a minimum of 5 minutes kills any viruses and bacteria that were in the water.
  • "Water is a freak and so it is one of my favorite molecules ever," Kate says. "It has these unique properties and we are surrounded by it constantly. We also are made of water. We have to drink water to survive...It's a really, really fun molecule to investigate."

Live on Monday: Does the US need one billion people?

What would happen if you tripled the US population? Matthew Yglesias and moderator Charles Duhigg explore the idea on Big Think Live.

Big Think LIVE

Is immigration key to bolstering the American economy? Could having one billion Americans secure the US's position as the global superpower?

Keep reading Show less

The surprising future of vaccine technology

We owe a lot to vaccines and the scientists that develop them. But we've only just touched the surface of what vaccines can do.

  • "Vaccines are the best thing science has ever given us," says Larry Brilliant, founding president and acting chairman of Skoll Global Threats. From smallpox, to Ebola, to polio, scientists have successful fought viruses and saved millions of lives. So what's next?
  • As Covaxx (formerly United Neuroscience) cofounder Lou Reese explains in this video, the issue with vaccines is that they don't work against "non-external threats." This is a problem, especially now when internal threats (things that cause cancers, Alzheimer's, diabetes, and other chronic illnesses) are killing people more than external threats like viruses.
  • The future of vaccine tech, which scientists are already working toward today, is developing safe vaccines to eradicate these destructive internal agents without harming our bodies in the process.

Keep reading Show less

Think everyone died young in ancient societies? Think again

In fact, the maximum human lifespan has barely changed since we arrived.

Photo by Juliet Furst on Unsplash
Surprising Science

You might have seen the cartoon: two cavemen sitting outside their cave knapping stone tools. One says to the other: 'Something's just not right – our air is clean, our water is pure, we all get plenty of exercise, everything we eat is organic and free-range, and yet nobody lives past 30.'

Keep reading Show less

Mystery anomaly weakens Earth's magnetic field, report scientists

A strange weakness in the Earth's protective magnetic field is growing and possibly splitting, shows data.

Surprising Science
  • "The South Atlantic Anomaly" in the Earth's magnetic field is growing and possibly splitting, shows data.
  • The information was gathered by the ESA's Swarm Constellation mission satellites.
  • The changes may indicate the coming reversal of the North and South Poles.
Keep reading Show less

Why social media has changed the world — and how to fix it

MIT Professor Sinan Aral's new book, "The Hype Machine," explores the perils and promise of social media in a time of discord.

Peter Macdiarmid/Getty Images for Somerset House
Technology & Innovation

Are you on social media a lot? When is the last time you checked Twitter, Facebook, or Instagram? Last night? Before breakfast? Five minutes ago?

Keep reading Show less