Hard or Soft?
HOW AM I SUPPOSED TO KNOW?
THEY BOTH LOOK EXACTLY THE SAME!
Hey there, Sapna here for Dnews.
From the outside, all water is seemingly the same: clear, mostly flavorless, two hydrogens,
one oxygen.
But once you get past the basics, water is actually pretty versatile.
It can be distilled, filtered, tap, bottled, and if you’re real fancy, there’s water
marketed as kosher, organic or kabbalah.
But did you know water can also be hard or soft?
No, this isn’t to describe how the water actually feels.
It actually has to do with its mineral content.
Water becomes ‘hard’ when it has a higher than normal concentration of minerals, primarily
calcium and magnesium.
Water picks up these minerals from rocks and soil as it flows through rivers, wells or
other waterways.
Soft water, on the other hand, has a low mineral content, either because it has not yet flowed
through rocks or wells - like rain water - or because the rocks it has come in contact with
have little to no soluble minerals.
But that isn’t to say that there is a set amount of hard and soft water on earth.
Because of the hydrologic cycle, our water fluctuates between hard and soft.
For instance, water that lives in oceans or streams tends to be hard, because it has already
picked up minerals.
But when this water evaporates and later becomes rain, it leaves these minerals behind and
becomes soft.
It’s important to note that water is not just ‘hard’ or ‘soft’.
It’s a spectrum, with water becoming more hard as its mineral concentration increases.
The United States Geological Survey classifies soft water as anything with less than 61 mg
of calcium carbonate per liter.
Above that is moderately hard water, then hard water, and very hard water.
According to the US Department of Energy, almost 75 percent of US homes have water that
is at least moderately hard.
Probably the best place to see the difference between hard and soft water is in the bathtub.
Soap is primarily made of a white solid called sodium stearate, which, with the help of water,
carries away dirt and oil.
Normally the components of soap dissolve in water, causing a really good lather, but in
hard water, the soap reacts with the minerals, forming insoluble compounds.
For example, the magnesium in hard water reacts with the stearate to form magnesium stearate..This
makes it more difficult to get a good lather in hard water.
It also cause the soap= scum you see on the sides of tub..
Hard water can also leave behind limescale, which occurs when water is heated or when
it sits for too long, and the minerals solidify as the water evaporates.
As you may have noticed in your own home, limescale looks gross and is really difficult
to get off of pots and faucets.
To avoid this, a lot of people choose to ‘soften’ their water.
An easy way to do this is by boiling water, which causes the calcium carbonate to evaporate,
leaving the remaining water soft.
Some cities also choose to soften their water, removing some of these minerals at the water
treatment plant before it goes out to consumers.
However there is another type of hardness called ‘permanent hardness’ that cannot
be boiled away.
Water becomes permanently hard when it flows through rocks with calcium sulfate, also known
as gypsum, which cannot be removed through boiling.
But despite its name, water with permanent hardness can be made soft.
The most common way of doing this is adding a chemical softener that filters out many
of the minerals.
But you may not be compelled to do this.
Because beyond difficulties with bathing and some household chores like laundry and dishes,
both hard and soft water are generally thought to be safe to drink, cook with and bathe in
especially if the water has gone through a treatment plant, at least in the United States.
However some cities do choose to soften their water, removing some of these minerals at
the water treatment plant before it goes out to consumers.
If you’re curious whether the stuff coming out of your tap is hard or soft, take a swig.
You can usually taste the minerals in hard water, whereas soft water is a bit more flat,
and can sometimes taste slightly salty.
So that covers fresh water, but what about salt water?
Why can’t we drink it?
Trace answers that question here.
Got any more questions about water?
Let us know in the comments and subscribe to DNews for more videos every day.