Saline water facts for kids
Saline water, often called salt water, is water that has a lot of salts dissolved in it. The most common salt found in water is sodium chloride, which is the same salt we use in food. You can find salt water in places like the oceans and some lakes.
The amount of salt in water is called its salinity. We measure salinity in "parts per thousand" (‰) or "parts per million" (ppm). For example, if water has 1,000 ppm of salt, it means there are 1,000 grams of salt for every million grams of water.
The United States Geological Survey (USGS) helps us understand different levels of saltiness.
- Slightly saline water has 1,000 to 3,000 ppm of salt.
- Moderately saline water has 3,000 to 10,000 ppm of salt.
- Highly saline water has 10,000 to 35,000 ppm of salt.
Seawater, like the water in the Atlantic or Pacific Ocean, is highly saline. It has about 35,000 ppm of salt. This means there are about 35 grams of salt in every liter of ocean water. Water can dissolve a lot of salt. At room temperature (around 20°C or 68°F), one liter of water can dissolve about 357 grams of salt!
Contents
What Makes Salt Water Special?
Salt changes how water behaves in interesting ways. When salt dissolves in water, it affects the water's properties.
Freezing Point and Density
One important change is the freezing point. Fresh water freezes at 0°C (32°F). But salt water freezes at a lower temperature. The more salt there is, the colder it needs to be for the water to turn into ice. This is why people sometimes put salt on icy roads to help melt the ice.
Salt water is also denser than fresh water. This means that for the same amount of space, salt water weighs more than fresh water. Because it's denser, objects can float more easily in salt water. This is why it's easier to float in the ocean than in a freshwater lake or swimming pool!
Measuring Saltiness
Scientists use a special tool called a salinometer to measure how much salt is in water. This tool helps them understand the salinity of different water sources around the world.
Related pages
See also
In Spanish: Agua de mar para niños
