Which water will hold up an heavy object longer salt water or tap?

Answer 1

Salt water weighs more than fresh water by 2.5%.

Yes. Salt water from the ocean weighs approx 8.55 lbs per gallon and fresh water weighs approx. 8.34 lbs per gallon, so that is 2.5% greater density of ocean water.

This is approximate because the more salt dissolved in the water the more it will weigh. (For example water from the Dead Sea would weigh more than ocean water) Also, as water gets colder its density increases until it is 4 degrees centigrade above freezing, at which point it begins to expand and then expands abruptly when it forms ice. The salt concentration affect freezing temperature and temperature effects density, so the 2.5% greater density is reliable only for the middle temperature range, away from freezing and boiling.

When one solute (the substance getting dissolved) dissolves in a solvent (the substance doing the dissolving) the solute fills in the spaces between the molecules. (Yes, it's true. There is actually space between molecules. If you would like to prove that to yourself, mix exactly 50 milliliters of water with 50 milliliters of rubbing alcohol and see how much you get. It's cool!!) (Lest you think this is always true, there are other examples of mixing two liquids which result in an increase in volume. That requires a more detailed explanation.)

When salt (the solute) dissolves in water (the Solvent), the ions of sodium separate from the ions of chlorine and enter the spaces between the water molecules. In this process, the salt adds to the mass of the solution but the volume added is less than the volume of the original salt. To be specific, if you added one cubic centimeter of salt to a liter of water, you would find the water increased in volume only about a half of a cubic centimeter. Since a cubic centimeter of salt weighs more than a cubic centimeter of water, the density of the salt water has increased.

So, salt water does weigh more than fresh water. The most amazing thing is that this difference in weight, more accurately the density, drives the largest ocean current in the world called the Thermohaline Conveyor. It's pretty cool.

Answer 2

Yes. Seawater is denser than fresh water (rain water) or chemically pure water. That's because it has a bunch of dissolved salts and minerals in it that add weight (mass) without significantly changing the volume.

Answer 3

Salt water weighs more (has a higher density) that tap water or pure water.

(Pure water, tap water and "fresh water" all weigh about the same and have very little salt or other dissolved minerals when compared to sea water or any water that is as salty as sea water.)

For example, the ocean is about 2.5% denser than fresh water. This causes greater buoyancy of objects and a swimmer can notice this easily.

The average density of water at the ocean's surface is about 1.025 g/ml or 2.5 % greater than pure water. This is due to the mass of added sea salts which is 3.5% or .035 g/ml. The added sea salts have only a small effect on the volume, so the resulting combination is more dense than pure water. If the salt added to water caused the volume to increase significantly, then the resultant combination could be less dense, but it is not.

One could get more technical and try to figure out how much volume is being taken up by the added salt, and thereby explain why the density increased by the amount observed. That turns out to be tricky and one concludes that the electrical charge of the ions is causing some sort of rearrangement of water molecules. That becomes an interesting question in itself, but getting an explanation at the molecular level is a different question.

Answer 4

Yes.

The ocean is about 2.5% denser than fresh water. This causes greater buoyancy of objects and a swimmer can notice this easily.

The average density of water at the ocean's surface is about 1.025 g/ml or 2.5 % greater than pure water. This is due to the mass of added sea salts which is 3.5% or .035 g/ml. The added sea salts have only a small effect on the volume, so the resulting combination is more dense than pure water. If the salt added to water caused the volume to increase significantly, then the resultant combination could be less dense, but it is not.

One could get more technical and try to figure out how much volume is being taken up by the added salt, and thereby explain why the density increased by the amount observed. That turns out to be tricky and one concludes that the electrical charge of the ions is causing some sort of rearrangement of water molecules. That becomes an interesting question in itself, but getting an explanation at the molecular level is a different question.

Answer 5

Yes this is why we float in it. If the substance you are in is a liquid that is heavier than you are you will float.

Answer 6

The salted water, because the density is greater.

Answer 7

it depends on your interpretation but it is much harder Salt water contains salt, so yes it is stronger.