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# Can water float on water?

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## Roquaya A

on 22 October 2015

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#### Transcript of Can water float on water?

Can water float on water?
Background research
After researching some background knowledge about my science experiment I found out...
I found out hot water has a less of a density then cold water. When you heat a substance the molecules move further apart, which causes a larger volume and a decrease in its density. Meanwhile cold water is the opposite, when a substance has a low temperature its molecules come closer together, which results in a smaller volume and an increase in density.
I also found out mixtures don’t have the same density such as pure substances. A mixtures proportions can always differ, leading to a different density mostly every time. Meanwhile pure substances have the same density. Its density does not depend on the amount of the substance, density is like a ratio if you add more of a substance then it mass and volume will also change leading to the same result it you take away the same amount you added.
Procedure / steps
Salt and fresh water ( Procedure )
Get two cups of water and pour in the same temperature water (measure temperature using thermometer)
In one of the cups label it salt and the other fresh
add about 3-4 spoons of salt to the cup you labeled salt.
Mix the salt and the water together until the salt dissolves
Get your laminated card and put it over salt water
quickly as your holding the card put it over the other cup of fresh water
slowly pull out the card and observe.
When done redo these steps but now put the fresh water over the salt water.
My Question
My question is seeing if water can float on water.
Variables / Constants
Controlled variable - No salt
Independent variable - amount of salt I put in the water, and Temperature of the water.
Dependent Variable - Density
Materials
2 glass cups with an equal size opening
Hot and cold water
salt
spoon
2 different colors of food coloring
laminated plastic card
Thermometer
scale
SAFETY
One safety issue while this experiment was
Be careful when tilting the hot water over the cold water because if its too hot it can burn you.
Key Words
Density : Compactness of a substance. You divide mass by volume to get the density of a substance. ( D = M/V )
Mass : is the weight of a substance
Volume : is the height of a substance
Mixture : a substance that is made from mixing other substances together. Mixtures don't always have the same density.
Pure substance : substances made out of only one type of atom.
By - Roquaya Aldhufari
Procedure / Steps
(continued)
( cold and hot water procedure )
Get two cups of water and pour hot water in the first and cold water in the second
In one of the cups label it hot and the other cold
Get your laminated card and put it over cold water
quickly as your holding the card put it over the other cup of hot water
slowly pull out the card and observe.
When done redo these steps but now put the hot water over the cold water
Observations
Salt and fresh water
When I put the salt water over the fresh water, the two waters mixed together.
When I put the fresh water over the salt water, the fresh water floated on top of the salt water.
I saw some mixing in between the two layers.
The cold water over hot water mixed
hot water over the cold water did not mix

Data / Results
What I found after doing this project is water can float on water. From my results I learned water can float on water when you change its density. Lease dense water can float on denser water, but dense water cant float on dense water.
Hypothesis
I predict water can float on water. From what I know I think if I change up the density of the water then I can get water to float on another layer of water.
Purpose
The purpose of this is to see if water can float on water. I want to see what can I change about the different bodies of water to get them to float on each other, otherwise the two bodies of water will combine.
Conclusion
This is the chart showing my results. The reason why different bodies of water floated on each other is because they were less dense then the water underneath them.
Salt and Fresh water
Fresh
salt
salt
Fresh
Since the fresh water is less dense then the salt water, it floated on the salt water.
cold and hot water
cold
cold
hot
hot
The hot water floated on the cold water because it was less dense then the cold water. The cold water couldn't float on the hot water because it was denser then it.
I wanted to see if water can float on water? I wanted to do this experiment because I found it interesting that the same substances can float on each other. I claim that water can float on water because I believe if I change the density of water, water can float on water. I know that the greater the density of the water is, I can get less dense water to float on it.In the real world my project can represent the “turning” of the rivers layers of water. This shows why during the summer the top of the water is warm and during winter its cold. The layers change due to their density, since warm water is less dense, during the summer it will be on top and the cold water will be on the bottom. In conclusion my hypothesis was correct, that water can float on water.
Bibliography for research

Science Buddies Staff. (2014, June 30). Can Water Float on Water?. Retrieved November 7, 2014 from http://www.sciencebuddies.org/science-fair-projects/project_ideas/OceanSci_p002.shtml

Archimedes. (2014, June 11). Retrieved November 7, 2014. from http://en.wikipedia.org/wiki/Archimedes

Temperature Affects Density. (n.d.). Retrieved November 7, 2014. from http://www.middleschoolchemistry.com/lessonplans/chapter3/lesson6

Mixture distribution. (2014, October 31). Retrieved November 7, 2014 from http://en.wikipedia.org/wiki/Mixture_distribution

Density. (n.d.). Retrieved November 7, 2014. from http://www.elmhurst.edu/~chm/vchembook/120Adensity.html

Questions and Answers - What is the difference between a compound and a molecule? (n.d.). Retrieved November 7, 2014. from http://education.jlab.org/qa/compound.html
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