Rivendell Science

Why is the ocean so Salty?

We started our year off doing what all kids love best. MIXING POTIONS! But I put an educational spin on it of course….

Our first topic unit is Oceans and one of the big questions is “How did the salt get into the ocean?”  If you are not certain, do not fret, many adults have never stopped to think about this, but kids do.  So we answered it – the way we usually do – through discussion and experiments.  Our answer is basically this. Rocks and minerals are washed down their watersheds and into the (keep it local) Poudre River, into the Platte, into the Missouri, into the Mississippi and finally the ocean.  BUT? that is all fresh water!  Yes….then comes the water cycle and up welling.  SO begins our study into salinity and currents.

During our salinity studies:

PK learned that salt water is YUCKY, but eggs float in it.  They are also learning what tools are in the lab and how to use them during their 10 minute free choice time each week.

YK learned that eggs float in salt water and fresh water floats on top of salt water too!

MK learned that eggs float in 3 tsps of salt water if it is hot and 16 tsps if it is cold and that they can make 3 layers of colored water just by mixing fresh and salt and layering it appropriately.

OK learned that the density of salt water changes according to the distance from an estuary and when the cold and warm waters mix they cause currents, but when the salt and fresh waters mix it causes up welling. Both occurrences are good for the Grey whale and its food source. They also learned that the currents are caused by the rotation of the Earth known as the Coriolis effect, but didn’t really care about that….what they did care about is the flush direction in toilets and if it is different on the Northern or Southern Hemisphere…I asked them to investigate a toilet here…but it is a MYTH….so they do care about the Coriolis Effect and believe EVERYTHING I SAY!

I hope you will teach them to ask more questions…I will try my best too- but seriously- look into it with your kiddo. http://factmyth.com/factoids/toilets-flush-backwards-in-australia/