Science Buddies: "Ask an Expert"

Hi,

I need your help quick. I found a project I want to do. Problem is, my teacher says I have to type it out. By that, I mean he says to type the problem it fixes and the science behind it into a google document. I have chosen to do the project that figures out how salty the sea has to be for an egg to float. I need some help figuring out the problem this fixes in real-life situations.

Thx,
jeepers13

Hi,

This kind of 'project' is designed to show you how salt concentration affects the density of water. Because it is a demonstration, It doesn't actually have a real-world application. http://www.scientificamerican.com/artic ... -in-water/

Thinking about saltwater and density reminds me of the Dead Sea which has a salinity of about 34%--ten times higher than the Mediterranean (https://en.wikipedia.org/wiki/Dead_Sea). Swimming in the Dead Sea, a person floats like a cork, and eggs would certainly float in that water. You could mention this as an attribute of salinity. That's why I prefer to swim in salt water!

The other aspect of salinity that comes to mind is the 'ocean conveyor belt' (https://en.wikipedia.org/wiki/Thermohaline_circulation). Sea water varies in density and the less salty the water is the less dense it is. The less salty water will float on top of more salty water. Temperature also affects the density of sea water. Warm water will float on cold water.

The Gulf Stream current carries warm water northward until it cools off enough to sink. However, if there is a large influx of fresh water as there was about 20,000 years ago when the huge glacial ice sheets melted in north America, the sea water is no longer dense enough to sink and the Gulf Stream stops. This can cause another ice age.

I hope you can use these ideas to write something about the affects of salinity on human life. If you have questions, let us know.

Good luck!

Sybee