Why is water essential for life?

Water is important for shielding and maintaining life; without it we will only live for a day or two. Hear Professor Søren Rud Keiding talk about why water is absolutely essential for life on Earth.

For you and me, water is absolutely essential. Our body contains roughly 70% of water and our heart is actually a very, very efficient water pump. We use blood to provide fuel and oxygen to our muscles when we have to move. And in the red blood cells we carry the oxygen. And water is able both to carry the cells and the nutrients. This is what we use to maintain our body temperature.

When we travel to outer space in the quest for finding life there we are not looking for people, we are looking for water. We hope that if we find water
we might also be able to find and meet new civilisations out there. Companies like Grundfos, where the driving force is actually to move water is therefore very, very important for shielding the life here on Earth.

A good example of the importance of water in maintaining and shielding life is how long we can actually survive without water. We might survive for a week or two without food. But without water we can only live for a day or two. This shielding was actually also very important roughly 3.5 billion years ago when life started here on Earth. Most scientists believe that life started in small water ponds. On these small water ponds, very, very simple biological organisms started and they were actually protected by the water.
When it got colder, they were also protected by the ice on top of the small water ponds. So water is actually essential for life. It is essential for maintaining life
but it's also very essential for shielding life. One of the most important properties of water is the ability to dissolve things in water.
So putting things in water is essential for transporting things in our body and elsewhere. The amount of salt, for example, that we process in our body every day is quite high. We have salt in the blood and the blood goes through the kidneys and the salt is exchanged in the kidneys. And this is not just sort of small quantities of salt every day. Actually, roughly one kilo of salt, this is roughly one kilo of salt is processed by the kidneys every day.

These processes of understanding how things go into water and how they go out again they're important in our kidneys, but they're also important when we have to understand how fresh water becomes drink water and how we desalinate salt water from the ocean. When we study the solar system and the universe and our galaxy we can actually see very, very far. We can see molecules on distant galaxies. We can see molecules many, many, many billions of light years away.
The interesting thing is that we can see that the molecules we have here on Earth are exactly the same as we have in outer space. So if you were to live on a different galaxy and have to pass a high school exam in physics and chemistry the textbooks and the study would be exactly the same as here on Earth.
We have the same molecules and the same atoms here as in the entire universe.

Course overview

Modules: 6
Completion time
Completion time: 30 minutes
Difficulty level
Difficulty level: Intermediate