- fill one glass about 2/3 way with water
- put NaCl in the other glass, about 1/8 full or so
- take a pinch of the salt, look at it closely (microscope helps!)
- record your observations (sketch and/or verbal description)
- add water to the salt, about 1/4 glass, stir/slosh til dissolved
- it's OK if some salt remains. Describe what happens
- If you have a microscope (40x is good), put a drop of water on some
salt grains and watch patiently under the scope - describe!
- add some food coloring to make the very salty water dark
- very gently pour the salty water into the fresh water
(it helps to tilt the fresh water glass to slow the pouring)
- observe and record the results!
We've got some explaining to do!
At least 3 good questions should come from your observations:
When ocean water comes into an estuary with the tide, it tends to settle to the bottom just like our model. As it pushes its way in, it usually gets a wedge shape - hence the title of this Web Site!
- Why are the NaCl crystals shaped like cubes?
- How did the salt disappear when water was added?
- Why does the salty water go to the bottom?