Like Dissolves Like Lab Activity
One of my favorite labs is called “Like Dissolves Like” where we simply mix different substances with water to determine if they’re polar or nonpolar. We start with food coloring, and a few things from my stock room. I’ll even take a kid with me to choose a “surprise” substance for the class to test. They determine the polarity of each substance, and need to draw the Lewis structures as well (some of those gigantic oils turn out to be a real pain).
The most interesting part of this lab is the Waterproof Sand. I lay out two plates of sand, one that I have treated so that it is nonpolar, and the other has been left untouched. I’m in love the look on my students’ faces when they interact with my homemade sand.
I put out some droppers for them to run the water down the hills and mounds in the sand. I also put out a beaker and spoons for them to drop the sand into. When they scoop out the sand and it is dry, they go wild. I love it.
This really gives my kids a good handle on the concept of micro vs. macro as well as using the macro to verify the micro. Plus they get some real life applications of the things they are learning in class. I love this experiment for so many reasons. If you are interested in the lab form I use to conduct the Like Dissolves Like Lab Activity in my classroom, you can find it here or click the storefront link at the top of this page. You can read more about my lab reports here.
How to Make Waterproof Sand
There are a few things you will need in order to make Aqua Sand.
- $1 Aluminum Pan (I got mine from the Dollar Store)
- $1 Plastic Spatula or Spoon that you are willing to throw away (or never cook with again)
- $17.32 for 5 pounds of “Decor Sand” or sand from the Hardware Store, but those come in 30-50 pound bags
- $16.49 for Kiwi Water Repellent Spray
Here’s how to do it:
- You pour the sand into the aluminum tray.
- Then spray the sand with the water repellent spray.
- Stir.
- Spray some more.
- Stir and spray some more.
My sand didn’t stick to itself at all, so I wasn’t stuck with some giant block of sand at the end. I let the spray dry to the sand for about 24 hours, and went out to spray some more. I sprayed around 8 ounces of water repellant onto the five pounds of sand. We have been using the sand for four years now and it is still holding up. Should it start to lose its waterproof quality, I will simply get another can of the water repellant spray and spray my sand again.
Definitely do this outside, because the water repellant spray is REALLY stinky. Plus having that spray residue on your countertops sounds horrible. I did mine out in the garage because I didn’t want my sand to blow away, but the garage was pretty stinky for some time. Make sure you are responsible about using this spray, and don’t use it around children or animals.
After using the sand with my students, I lay it out on a tray in my stock room for it to dry out, which usually takes a day or so. It’s dry in no time. I store it in a food storage container with a tight seal. This keeps it free of bugs and keeps it from spilling all over my classroom.
My Like Dissolves Like lab is such a hit. The kids remember it so well because the sand is so “mind blowing.” This in itself makes it so easy for me to call on this lab and the adage, “like dissolves like” in all of my lessons on macrochemistry and intermolecular forces. Plus it’s fun! The kids also write a very thorough lab report using this lab rubric that you can get for free here.
Read more about my green chemistry lab activities here!
*This post contains affiliate links, meaning that if you make a purchase through the link I make a small commission, though this does not affect the price of the item for the customer.
