Freshwater vs Saltwater

1) What are the differences between salt water and freshwater?

Consider the following:

a) Appearance -

b) Buoyancy -

c) Density -

d) Other differences -

2) How do objects float  in water? How do large, heavy objects (like ships) float on sea water? Why do some objects float and others don’t?

Use Google and use Youtube!

Check out these resources to help you learn more:

- http://www.youtube.com/watch?feature=endscreen&NR=1&v=U7e6bmqYoS8

- http://www.youtube.com/watch?v=MzsORE0ae10

Bonus Question: Fresh water from rivers mixes with salt water when the river reaches the sea. What happens when fresh water mixes with saltwater?  Does the freshwater mix completely with the saltwater? Does it float above the saltwater? Or does it sink below the saltwater?



12 comments ↓

  • #   adrianbisram2012 on 12.12.12 at 7:05 pm     

    1.a) Fresh water is more clear then salt water.
    b) salt water has more Buoyancy then fresh water does.
    c) Fresh water has a density of 1.0 while salt water has a density or 1.025.
    d)Fresh water is lighter than slat water. therefore, fresh water floats on top of salf water.

    2.) If the denstiy of the object is less than the water the water has enough power to push the object up to float.


  • #   Gurkaran on 12.12.12 at 7:06 pm     

    Apperance-The differnce between salt water and fresh water is that salt water is more foggy than fresh water because of the salt,and fresh water is more clear than salt water cause there is nothing dissolved in it.
    buoyancy-Objects can float on salt water but not fresh water.If you were to go swimming in a pool you would float and if you were to go in a ocean you would not because of the salt water
    Density-salt water is more thicker than fresh water, adds mass to water to make it more dense.


  • #   lamarr2012 on 12.12.12 at 7:06 pm     

    1. a)Fresh water looks more clear then salt water does
    b) salt water has more Buoyancy then fresh water
    c)Fresh water has a density of 1.0 while salt water has a density of 1.025.
    d)Fresh water is lighter than salt water. Therefore, fresh water floats on top of salt water.

    2.If the density of the object is less then the water the the water has enough power to push the object up to float. Water is usally heavier then the object thats on it so it can hold the weight.


  • #   Faizal on 12.12.12 at 7:06 pm     

    Appearance – The difference between fresh water and salt water is that fresh water is clear and salt water is foggy.

    Buoyancy – Salt water more has more Buoyancy than fresh water because objects can float on salt water. object do not float on fresh water.

    Density – Salt water is thicker than fresh water because salt adds mass to the water and makes it more dense than it would be without salt.

    Other differences – Salt water is undrinkable and fresh water is drinkable.salt water may cause you to die.


  • #   Hitlersgasbill on 12.12.12 at 7:10 pm     

    Salt water contains more mineral salt versus fresh water which has only a little. Fresh water is much less buoyent then salt water. Salt water is reallt dangerous to drink unlike fesh water. Fresh water is much harder to find unlike salt water. Salt water is harder to see out of versus fresh water were its much cleaner.


  • #   Safiyyah on 12.12.12 at 9:32 pm     

    Q1: The differences between fresh water and salt water are:

    1: Fresh water doesn’t have enough of the buoyancy as salt water has to allow things to float easily.

    2: Salt water has more salinity and the density in salt water is a lot higher than fresh water. That being said salt water is much heavier than fresh water.

    3: Salt water can be deadly for you if you drink too much as it dehydrates your body.

    4: The ecosystems around salt and fresh water are completely different.

    Q2: For an object to float in water, the density of the object has to be less than the water’s, if it is then the water will have the power to push the object upwards to float, if the object is much heavier than water, then the object will have the power to break through the surface of the water, and if the density of the object isn’t very high nor too low, the object will stay in the middle of the water.

    Whether or not something will float depends mostly on how big it is and how much it weighs.
    Density is how much something weighs.
    If an object weighs more than the same weight of water does, it can push the water out of the way. So if it’s more heavy than the water, and it will sink in the water.
    If something weighs less than water does, it’s less dense than water , so it will float in water.
    So if an object is more dense than the density of water it will sink, if the object is less dense than the density of the water it will float.

    Bonus Question:
    When fresh water and salt water mix it creates “Brackish Water”
    Fresh water does float above salt water and the reasoning is because fresh water is lighter than salt water.

    Resources:

    http://www.differencebetween.net/science/nature/difference-between-salt-water-and-fresh-water/

    answers.yahoo.com/question/index?qid=20090822065213AAeMStL

    http://www.webinnate.co.uk/science/week3.htm

    wiki.answers.com/Q/Why_do_some_things_float_on_water_while_others_do_not

    en.wikipedia.org/wiki/Brackish_water

    geography.about.com/library/misc/ucghyben.htm


  • #   Gurkaran on 12.12.12 at 9:35 pm     

    Fresh water vs Salt water
    Appearance-Differences between salt water and fresh water is that salt water can be more foggy than fresh water due to the amount of salt dissolved into it. Fresh water is more clear than salt water that is why you can see through it.
    Buoyancy- salt water is more buoyant than fresh water Salt water is more denser than fresh water . It is because salt is more denser than water and adding salt to water that resulting solution is denser than pure water.
    Density- Salt water is more thicker than fresh water.
    The salt in the water adds mass to the water to make it more dense.
    Other differences- The differences between these too are that we can not live with drinking salt water if we would it will just come right out cause your body cant take it. Fresh water is what we need in order to survive.
    2. objects float in water because they are less dense than water. Other objects do not float in water because sometimes there is more mas than needed
    Bonus Question-What happens is that when fresh water does mix with salt water they both just dissolve into one main body of water cause there is more of that then there is of fresh water.


  • #   xV1b0LtS on 12.13.12 at 3:06 am     

    1) What are the differences between salt water and freshwater?

    Consider the following:

    a) Appearance – How something looks
    In fresh water it will look like there are absolutely no particles in the water but, in salt water it will not look clear. You will see salt if it’s really concentrated and most likely you’ll see some sand!

    b) Buoyancy – The ability to float in water or other fluid or
    the power of a liquid to keep something afloat.

    When you put something in water, it has to push enough water to make room for its entire volume before it can sink.

    When you dissolve salt in water, you’ve just added more STUFF, or MASS, to the same volume of water. Saltwater weighs the weight of the water plus the weight of the salt.

    Salt isn’t very heavy, but it’s enough to make the difference when you drop something that just barely has enough weight to sink in freshwater.

    c) Density – Density is basically how much something weighs.

    I think that salt waters density is more than fresh water because of all the salt in it!

    d) Other differences – Fresh water ways less, comparing to salt water because when you weigh the freshwater, you’re only looking at how much the water ways but, when you weigh salt water you’re looking at how much the salt and water weighs!

    2) How do objects float in water? How do large, heavy objects (like ships) float on sea water? Why do some objects float and others don’t?

    If the density of the object (boat) is less than water, then water has the power to push the object up to float, if the object (boat) is so much denser than water, then the object (boat) will have the power to break through water, and if the density of the object isn’t very high nor too low, it would stay in the middle of the water.

    Bonus Question: Fresh water from rivers mixes with salt water when the river reaches the sea. What happens when fresh water mixes with saltwater? Does the freshwater mix completely with the saltwater? Does it float above the saltwater? Or does it sink below the saltwater?

    When the fresh water from rivers mixes with the salt water in the sea the water dissolves. Dissolves means go into, so the fresh water goes into the salt water and it turns into salt water! If there wasn’t salt water then when the fresh water reaches the sea it would stay as is (fresh water)! It would depend on the salts concentration for it to completely turn into salt water. Fresh water floats above the salt water because it is less dense than the salt water!


  • #   Shubham on 12.13.12 at 9:07 pm     

    1. a) Appearance- The difference between salt water and fresh water is that salt water is very foggy inside the cup/container etc. But fresh water is clear and isn’t foggy.

    b) Buoyancy- Salt water has more buoyancy than fresh water because the objects on salt water float but in if put in fresh water, the objects would sink. For example: If you have floated in ocean before, you may notice that it’s much easier to do so than it is to keep afloat in a swimming pool. Salt is the reason why this is. Salt adds mass to the water of the water and makes it denser than it would be without salt.

    c) Density- Salt water is more thicker because salt adds mass to the water so that objects can float on it.

    d) Other Differences- Salt water is not potable, very salty and if you take in too much salt water you would probably die. But fresh water is potable, and keeps you hydrated. Also when you drink salt water there is a risk of dehydration. And if you put a fish that is in freshwater and put it in saltwater it will not be able to survive.
    2. Objects can float on water because they have a lot of air inside the objects so that it doesn’t overweigh and sink. The reason why ships don’t sink is because as i mentioned they have a lot of air inside the ship and also in sea it’s saltwater and saltwater has more buoyancy and all the salt takes up the mass of water and lets the ship float. The reason why other objects don’t float is because they don’t have air inside of the objects so that it could float and also it is probably because it’s very big and weighs a lot.
    BQ: When freshwater mixes with saltwater, water containing the most salt dissolved (saltwater) forms the bottom layer and the less dense water stays at the top (freshwater). Freshwater does not mix with saltwater.


  • #   lak 28 on 12.16.12 at 2:18 am     

    A. Saltwater is not as clear as freshwater and saltwater looks deeper because the salt makes the water translucent so you cannot see most of the water.

    B. The buoyancy of an object floating in water is greater in salt water than in fresh water due to the dissolved salt giving the water a greater density.

    C. Salt water is more dense than fresh water because salt water has more mass than fresh water, according to the formula D=M/V (D is the density, M is the mass, V is the volume).

    D. People cannot properly consume saltwater, NaH is also corrosive, and saltwater is also ugly judging on this URL: http://natt8e.edublogs.org/files/2012/12/Salt-Fresh-water-experiment-day-1-2011-w6nthr.jpg, also freshwater is awesome!!!

    2. Large objects float in water because they displace more water than small objects. Whether an object floats or not is a matter of whether the object that’s in the water weighs more than the water it pushes (water is 1 KG/DM^3).

    3. If saltwater and freshwater are added together, this will dilute the concentration of the dissolved ions in the saltwater will be distributed to the entire body of water which will make the whole solution less dense.


  • #   Anjalee S on 12.16.12 at 9:45 pm     

    1. There are several differences between saltwater and freshwater.

    1a. Visually salt water looks more blurry and unclear its colour is very white and grainy saltwater is translucent. The fresh water looks clear and very transparent.

    1b. Buoyancy – the ability of an object to float in water or fluids
    Saltwater is more dense (heavy) than freshwater, it will have a more/ greater buoyant force than freshwater.

    1c. Density- Salt water is more dense than freshwater therefore freshwater will “float” above saltwater. Salt water is heavier than freshwater.

    1d.
    • Saltwater freezes at a colder temperature than freshwater (-1.8 degrees Celsius)
    • The salinity concentration of saltwater is about 3.5%
    • Fresh water has less than 1% of dissolved salts
    • Saltwater can be deadly if ingested
    • Saltwater is found in rivers and streams
    • Freshwater is found in rivers and streams

    2. Objects float in water based on its density they have to be less dense than the water the object is in.

    Large heavy objects such as boats or ships are filled with a lot of air so technically they are less dense. Also large boats have a larger surface area which has a larger buoyant force.

    Large objects float and other objects don’t because small objects such as a small penny has no air components and a small surface area. Since a penny has no air trapped in it the penny is denser than the water.

    Bonus Question
    Fresh water is lighter/ less dense than salt water so the fresh water “floats” on top of the saltwater. The fresh water does not completely mix with the salt water. It does not sink below because the salt water is denser.


  • #   lesziquebrowne2012 on 02.12.13 at 1:23 am     

    the differences between slat water and fresh water is salt water is more dense then fresh water the reason that the diet coke floats it because its more dense than normal coke Fresh water is more clear then salt water.
    b) salt water has more Buoyancy then fresh water does.
    c) Fresh water has a density of 1.0 while salt water has a density or 1.025.
    d)Fresh water is lighter than slat water. therefore, fresh water floats on top of salf water.


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