It’s almost summer! If you’re from the Midwest, you know that this was a LONG WINTER. It’s time to take advantage of this beautiful weather and get outside! Today, we’re going to learn a few different ways to have fun with sidewalk chalk.
Let’s get thinking:
- Where do you usually see chalk?
- What do you think chalk is made of?
- Is chalk natural or manmade?
Write down your ideas and then let’s get rolling!
First, let’s learn a little bit about where chalk comes from. We did a blog on chalk two years ago, so we’ll dig up some information from our previous research:
Where does chalk come from?
Did you know that chalk is actually a rock? Chalk comes from the mineral limestone, and is soft, white, and porous. The scientific name for chalk is calcite, or calcium carbonate (CaCO3). Most of the chalk you use today is no longer made of calcium carbonate, but is instead made of a similar mineral called calcium sulfate, or gypsum.
Where does chalk occur in nature?
Chalk is actually mined from chalk deposits, which are found in different areas around the world such as Germany, England, and Denmark. These chalk deposits were formed over millions of years from microscopic calcite shells called coccoliths. Over time, the build-up of coccoliths created formations like the ones below!
People have been using chalk for ages, as archeologists have found chalk cave drawings from early humans dated back to 40,000 BC. Artists used chalk by grinding calcium carbonate (the chalk found in nature) and mixing it with water and pigments. Teachers commonly used chalk in the 20th century on slate blackboards. Now, we’re still using chalk for art and fun today.
How to make sidewalk chalk:
This is the recipe we used in our previous activity to make your own homemade sidewalk chalk.
- Toilet paper tubes
- Duct Tape
- Bucket or large mixing bowl
- Wax paper
- Tempera paint (available at Target, Amazon, and most craft stores)
- Plaster of Paris (gypsum)
- Cookie sheet
Here’s what to do!
- Collect about six toilet paper tubes. This is what you will use for your chalk mold. Cover one end of each tube with duct tape. Make sure the tape is secure so none of your chalk mixture will leak out the end.
- Measure a 6x6 inch piece of wax paper and cut it out. Roll the wax paper square up and place it inside the unsealed end of one of your cardboard tubes. The wax paper is to keep your chalk mixture from sticking to the inside of the cardboard tube.
- Repeat step 2 until you have all six of your paper tubes lined with wax paper.
- Measure out 3/4 cup of warm water and pour it into your bucket.
- Measure 1 1/2 cups of plaster of Paris and sprinkle it into the warm water. Stir as you sprinkle. The plaster will begin to harden in the next half hour, so you will want to work quickly.
- Divide the plaster of Paris mixture into six different bowls. Pick six different colors of tempera paint, and add about 3 tablespoons of paint to each bowl. Stir until the color is evenly distributed.
- Place each cardboard tube tape-side down on a cookie sheet, then pour the colored plaster of Paris mixture into each tube (one color per tube).
- Move the sheet of tubes to a place where they won’t be disturbed. It will take about three days for the chalk to dry completely. Peel the tubes and wax paper off, and voila! You have your own homemade sidewalk chalk!
- BONUS: To spice it up, add glitter or other materials for a fun texture! For nighttime fun, mix in a little Glow in the Dark Paint with your plaster of Paris mixture before it dries. You’ll have pictures that show up at night!
If you’re looking for a new way to experience sidewalk chalk, you can try sidewalk chalk paint! This “chalk paint” really isn’t chalk at all. Instead of gypsum, sidewalk chalk paint utilizes cornstarch. It’s just another great way to have fun and get outside!
Basic Sidewalk Chalk Paint
YOU WILL NEED:
- Food coloring
- Small bowls or cups
- Paint brushes
Here’s what to do!
- Pour a cup or so of water into the containers and add several drops of food coloring or craft paint into each.
- Mix about 1 cup of cornstarch into each container of water.
- Stir the cornstarch and water together until smooth. If it’s too thick, just add more water. A little goes a long way! If it’s way to runny, sprinkle a little more cornstarch.
- Paint away!
Now that you know how to make sidewalk chalk paint, let’s make it a little more exciting. You may have used baking soda and vinegar in other experiments. If you have, you probably know that baking soda is a base, and vinegar is an acid.
When mixed together, acids and bases cause a chemical reaction. This chemical reaction produces a gas called carbon dioxide. In this case, c02 = BUBBLES AND FIZZING FUN! Let’s try it out!
Here’s what to do!
- Follow the directions for Basic Sidewalk Chalk Paint, but sub half of the cornstarch for baking soda.
- Dump vinegar into a spray bottle and set aside for later.
- Create your sidewalk art with the sidewalk chalk paint baking soda mixture. For more abstract art, put your paint into squeeze bottles!
- Spray your art with vinegar and watch it bubble!
For more fizzing fun, check out:
Use baking soda and vinegar to blow up a balloon
Make your own film canister rocket
Exploding glow in the dark art
Blackboard chalk and whiteboard pen. History of Pencils. http://www.historyofpencils.com/writing-instruments-history/blackboard-chalk-and-whiteboard-pen-history-and-future/
Chalk drawings. Encyclopedia of Art. http://www.visual-arts-cork.com/drawing/chalk-drawings.htm
Stewart, M. Magic sidewalk chalk paint. https://www.youtube.com/watch?v=bdx3Qj4zbJQ
Vacker, M. Homemade sidewalk chalk. PBSParents: Crafts for kids. http://www.pbs.org/parents/crafts-for-kids/homemade-sidewalk-chalk/
Carolyn. How to make sidewalk chalk paint. Simple Play Ideas.