Great Salt Lake Science

We could not possibly study Utah without talking about the Great Salt Lake, and it really doesn't mean much to a six year old and a four year old to just say that the average salinity of the ocean is 3.5% and the average salinity of the Great Salt Lake is 15%.  We had no choice but to try to recreate the Great Salt Lake and compare it to the ocean and a freshwater lake.

Materials:
3 glass jars
water (warm water is best to try to dissolve the salt)
red, yellow, and blue food coloring
2 1/2 tsp salt

1. I placed three Mason jars on the counter
2. I labeled the three jars:  freshwater lake, ocean, and Great Salt Lake
3. I put 100 ml of tap water in the freshwater lake jar
4. R added 1/2 tsp of salt to 100 ml of water in the ocean jar
5. C added 4 tsp of salt to 90 ml of water in the Great Salt Lake jar
6. I had to take control of the food coloring because I only wanted one drop of food coloring in each jar and kids just can't do one drop.  So, I added one drop of blue to the freshwater, one drop of yellow to the ocean water, and one drop of red to the Great Salt Lake water.
7. Then we observed how the food coloring mixed in the different types of water.

I was really surprised to see the food coloring mix right away in the freshwater and ocean water, but linger or float on top of the Great Salt Lake water.  C and R thought it was pretty cool.

We also managed to get the freshwater to float on top of the Great Salt Lake water.

Ideally, you should be able to get the ocean water to float on top of the Great Salt Lake water and then get the freshwater to float on top of the ocean water, but I couldn't make it happen.  We repeated this experiment three times, but you have to have a real steady hand to make the water float right and I think it's important to have the salt dissolve really well too.  Regardless, it was all pretty cool.  I know I have succeeded in creating a cool science project when T (age 13) wants in on the action, and this time he did.  

All three kids continued playing with the colored water and the medicine droppers for quite some time afterward!  And, this is how we spent our time yesterday when there was no school.  We also went to vote together (well, T didn't come with us) - that's one educational day without a classroom in sight!

I will be linking this to Science Sunday at Adventures in Mommydom.