Science Buddies: "Ask an Expert"

For my science fair project I am seeing if water can float on water due to tempurature change and/or dissolved salt. These are a couple of questions I need to answer for my background research:

How does the density of water change as a function of temperature?
How does the density of water change as a function of dissolved salt?

Thanks

Hi,

Here is a water density calculator page that computes density as a function of temperature and salt content:

http://www.csgnetwork.com/h2odenscalc.html

Here is a table of water density as a function of temperature:

http://faculty.cbu.ca/chowley/chem201/dh20vstemp.htm

Here is a graph of water density vs. temperature:

http://www.ce.utexas.edu/prof/KINNAS/31 ... nsgif.html

You can also find extensive tables of density of salt solutions and water at various temperatures in these reference books which your science teacher likely owns or can be found in most libraries:

Handbook of Chemistry and Physics, edited by Charles D Hodgeman (Chemical Rubber Publishing co.)

Handbook of Chemistry, by Norbert Adolph Lange

Have fun with the project!

Barrett Tomlinson

I suggest using food coloring (i.e. red for hot and blue for cold) but remember to heat and cool the water with the coloring in isolated solutions. Create a water tank that has holes coming from two sides-one containing the red water and the other the blue water then release both tunnels of water and then check to test your experiment. Do it several times and calculate. Also try to graph your results.
Hope it helps.