How to turn table salt, glue and a little food coloring into a work of art
Discovery Place Science
Salt is hygroscopic, which means it can absorb both liquid and water vapor in the air. This fun activity is a great way to learn more about absorption.
The salt we sprinkle on our glue design in this activity absorbs the water (and paint color) through a chemical reaction. When the water touches the salt, the water and the ink are absorbed and spread throughout the salt.
This fun activity is demonstrated in our very own bodies every day when we eat foods that are high in salt. Salt is absorbed through our small intestine and enters the bloodstream, which makes our blood saltier. The salt pulls water from the inside of our cells, a process called osmosis, to even out the amount of salt in our bloodstream.
If you have a lot of water inside a cell and only a small amount outside the cell, some of the water will move outside the cell to balance everything out; this works in the opposite direction as well. Once the process of osmosis is over, a signal is sent to the brain that the body needs more water; we feel it when we are thirsty.
Now, let's learn more about absorption while putting our art skills to the test!
- Card Stock or mixed media paper
- Bottle of white glue
- Table salt
- Food coloring or watercolor paints
- Pipettes, droppers or brushes
- Small plastic cups
- Tray, baking dish or box
1. If you are using food coloring, fill plastic cups up with about a half a cup of water. Then, add one color of food coloring to each cup. The more food coloring you use, the darker the color will be. If you are using watercolor paints, make sure that you put a lot of water on the paint. The more soaked it is the better.
2. Next, draw your design on a piece of heavy paper.
3. Trace over your writing or drawing with white glue.
4. Place your paper in a tray (with edges), baking dish or box and sprinkle salt over the glue.
5. After the glue is well coated, remove the paper from the box and gently shake the paper to remove any extra salt.
6. Once the glue has dried, fill your pipette or paintbrush with a lot of paint and gently drop the paint on the salt. Then, observe as the color spreads.