Sunday, May 30, 2010

Cave Experiments, Science Sunday

Little J is fascinated by rocks and caves, so I thought we could do a little crystal growing here at home.  I found this website, "Science Kids at Home" that has instructions as to how to set up this experiment.  It will take a couple of days to grow and we'll do a follow up post when we've finished.  "Caves, A True Book" by Larry Dane Brimner is one of the better books for kids that we have found.  It explains in simple terms how caves are formed.  We are also planning a trip to Luray Caverns this summer. 


We used about 1 1/2 cups of water.

It took about 1 cup of epsom salt to saturate the water.

Once Little J had dissolved as much epsom salt as he could, I heated it slightly in the microwave and added more epsom salt until it would no longer dissolve and finished our supersaturated solution.

We used a piece of paper towel weighted with paper clips for our string.  We wet it in solution first to get it started.  The trick is getting it to hang between the glasses so that it drips, but not too fast.

The experiment represents how rain water seeps through the ground, forms a slight acid with the elements and dissolves the limestone in the ground to form a cave and start stalactites(ceiling) and stalagmites (ground) growing.  Obviously this isn't a perfect demonstration, but fine for a 5 year old.  We were also able to discuss the terms saturated solution and supersaturated solution. 

We had to reposition the string a little and then we put a small piece of paper towel beneath the drips as it was dripping too fast and spreading out.  This seems to have stopped the problem and you can see the crystals starting to form on the tray. 

Go here to see our final result.


An Almost Unschooling Mom said...

We tried this with sugar water, and string, but it didn't work at all. The paper towel is a much better idea.

Ticia said...

I am so doing this whenever we go back to the local caves. Or maybe even before. I wonder if it would work with the sugar crystal recipe as well..... hmmmm.... Something to try.

MaryAnne said...

What a cool idea! I think my kids would enjoy this when they are a little bit older.

Debbie said...

This is really a cool experiment. I am going to keep this in mind for when we study caves.

Unknown said...

This is really interesting!! I don't remember learning about caves in such a fun way. Thanks for sharing.

Unknown said...

I will SO be bookmarking this experiment for our future units- so interesting!

Tricia said...

Thanks for popping over to! I love your site!

I also tried this with sugar water and found it didn't work - will have to try your idea!