Have you ever wondered how glass is made? Glass can form naturally over time or it may be man-made. Most of the glass you see every day is man-made, but all glass has the same main ingredient--sand! The sand must be heated to extremely high temperatures in order to melt, and that melted sand changes from opaque to transparent as it cools.
Below is a picture of volcanic glass. This glass was formed from sand that was rapidly heated in a volcano and then cooled.
Check out this video to watch how glass is made:
How are we going to do this? When you add sugar to water and stir, the sugar dissolves and creates a sugar solution. You may have experienced this if you’ve ever made Kool-Aid--the powder disappears into the water and seems to become one with the liquid. If you mix water and sugar together but then leave the sugar solution alone until the water evaporates, sugar that was once dissolved will remain! Adding a few simple ingredients in this activity (corn syrup and cream of tartar) prevents the solution from crystallizing back into sugar and leaves you with a transparent solid--sugar glass!
* Granulated sugar
* Cream of Tartar (you can find this in the spice section of any grocery store)
* Light corn syrup
* Measuring cups/spoons
* Cookie sheet
* Candy thermometer
* Stirring spoon
* Non-stick cooking spray
* Food coloring
* Fork or toothpick
Here’s what to do!
1. Use measuring cups and spoons to measure out 1 3/4 cup granulated sugar, 1 cup water, 1/2 cup light corn syrup, and 1/8 teaspoon cream of tartar.
2. Combine all ingredients in a saucepan.
3. Spray your cookie sheet with non-stick cooking spray and set it off to the side.
4. Turn the burner on low/medium in order to heat your ingredients slowly. If the solution gets too hot, it will caramelize and turn a yellowish color. Stir constantly as the solution heats up.
5. Once your solution turns clear, you can stop stirring and place the candy thermometer in the saucepan. The solution will begin to boil slowly, but that’s okay. Just make sure not to get splashed!
6. Keep a close eye on the thermometer and remove the saucepan from the burner once the solution reaches the hard crack stage (between 300 and 310 degrees Fahrenheit).
7. Carefully pour the solution into the cookie sheet.
8. Now let your creativity shine! Sprinkle your choice of food coloring onto the cookie sheet of syrup. Next, use a fork or toothpick to swirl the dots of color throughout the syrup. Have fun with it! Just BE CAREFUL to not touch the hot syrup!
9. Leave the cookie sheet in a safe place to cool down. Check back a few hours later and remove your sugary, beautiful creation!
For more science activities that involve crystallization, check out:
For more science activities involving baking/cooking, check out: