Why is water densest at 4 celsius

The density decreases as temperature increases. These clusters are free to move relative to each other, so water is still liquid.

As the temperature of warm water decreases, the water molecules slow down and the density increases. The molecules are still slowing down and coming closer together, but the formation of clusters makes the molecules be further apart. Chemistry Measurement Density. Ernest Z. We all are aware that all matter shrinks when it is cooled resulting in an increase in the density.

We would therefore expect that water would have high density at the freezing point. Strangely enough for the liquid state, water is the densest at 4 degrees C, and therefore it stays on the bottom whether it's in a glass or in an ocean.

If you chill water below 4 degrees, it starts to expand again. The density of ice is about 90 percent that of water, but that can vary because ice can contain air, too. That means that about 10 percent of an ice cube or iceberg will be above the water line.

This property of water is critical for all life on earth. If water was most dense at the freezing point, then in winter the very cold water at the surface of lakes would sink, the lake could freeze from the bottom up. And, with water being such a good insulator due to its heat capacity , some frozen lakes might not totally thaw in summer. The real-world explanation of water density is actually more complicated, as the density of water also varies with the amount of material that is dissolved in it.

Water in nature contains minerals, gasses, salts, and even pesticides and bacteria, some of which are dissolved. As more material is dissolved in a gallon of water then that gallon will weigh more and be more dense— ocean water is denser than pure water. We already said ice floats on water because it is less dense, but ice of a special kind can be denser than normal water.

Heavy water, D 2 O instead of H 2 O, is water in which both hydrogen atoms have been replaced with deuterium, the isotope of hydrogen containing one proton and one neutron. Heavy water is indeed heavier than normal water which contains a tiny amount of heavy water molecules naturally , and heavy-water ice will sink in normal water. The instrument to measure the density of a liquid is called a hydrometer. It is one of the simplest of scientific-measuring devices, and you can even make your own out of a plastic straws see links below.

More often, though, it is made of glass and looks a lot like a thermometer. It consists of a cylindrical stem and a weighted bulb at the bottom to make it float upright. The hydrometer is gently lowered into the liquid to be measured until the hydrometer floats freely. There are etched or marked lines on the device so the user can see how high or low the hydrometer is floating.

In less dense liquids the hydrometer will float lower, while in more dense liquids it will float higher. Since water is the "standard" by which other liquids are measured, the mark for water is probably labeled as "1.

Hydrometers have many uses, not the least being to measure the salinity of water for science classes in schools. They are also used in the dairy industry to get estimates of the fat content of milk, as milk with higher fat content will be less dense than lower-fat milk. Hydrometers are often used by people who make beer and wine at home, as it offers an indication of how much sugar is in the liquid, and lets the brewer know how far along the fermentation process has gone.

Do you think you know a lot about water properties? Looking at water, you might think that it's the most simple thing around. Pure water is practically colorless, odorless, and tasteless. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more.

Why is density of water maximum at 4 degree celsius? Ask Question. Asked 4 years, 2 months ago. Active 1 year, 5 months ago. Viewed 12k times. We were having a discussion to this question in class and I could gather the following points.

Here's what I couldn't understand: 1 I cannot understand why trapping of gases results in increase of volume. Improve this question. Arishta Arishta 3, 6 6 gold badges 36 36 silver badges 55 55 bronze badges.