Chalk Isn't Chalk and Why an Elephant's Nose is Called a Trunk

TL;DR

Chalk and gypsum, commonly used in classrooms and construction, have ancient origins and a variety of applications.

Transcript

Ubiquitous in many classrooms since the 19th century, chalk and chalkboards are familiar to most of us. White, powdery and prone to sticking to those surfaces where it is put (and just as easy to wipe away), chalk and its accompanying board are excellent instructional aids. Notably, however, most chalk today isn't technically chalk at all, but gyps... Read More

Key Insights

• ⌛ Chalk and gypsum have been used since ancient times for various purposes.
• ❓ Chalk is made of calcium and oxygen combined with carbon, while gypsum is made of calcium and oxygen combined with sulfur.
• 😒 Both chalk and gypsum can be turned into fine powders and shaped for different uses.
• 🈸 Gypsum is more abundant and widely used in industrial applications compared to chalk.
• 😋 Gypsum is mined in more than 90 countries and the US alone produces over 30 million tons annually.
• ❓ Chalk is commonly used in classrooms for writing and drawing purposes.
• 😎 Gypsum is used in construction, glass manufacturing, and as a fire-resistant material in drywall.

Questions & Answers

Q: How are chalk and gypsum formed?

Chalk is formed from the calcium in the bodies of marine organisms, while gypsum is formed from the calcium and salt left behind as the ocean evaporated.

Q: What are the main uses of chalk and gypsum?

Traditionally, chalk has been used for writing and drawing, while gypsum is used in construction, glass manufacturing, drywall, and a variety of other applications.

Q: Why has gypsum replaced chalk for writing on blackboards?

One reason is that gypsum is less dusty than chalk. Additionally, gypsum is more abundant and is used for a wide range of industrial applications.

Q: What are some other interesting uses of gypsum?

Gypsum can be used in fertilizers, soil conditioners, hair products, tooth plasters, mushroom growing, beer brewing, and even to bind tofu.

Summary & Key Takeaways

• Chalk and gypsum have been used for thousands of years, with chalk being found in cave paintings dating back to 40,000 BC.

• Chalk is made of calcium and oxygen combined with carbon, while gypsum is made of calcium and oxygen combined with sulfur.

• The main difference between chalk and gypsum is that chalk is a base and gypsum is a salt.