Curious Objects

Spherical Chalkboard

Spherical Chalkboard

You asked, we answered!

NAME OF OBJECT: Spherical Chalkboard

Who uses this object?

This object was used starting in the 18th century by mathematicians, geographers, astronomers to make sense of all things spherical, or phenomena occurring on curved (rather than flat surfaces).

Where is it used?

This is a historical artifact – not used much in today’s classrooms, surprisingly!

What does it do and how do you use it?

Not used very much now – although would still be beneficial as a physical model. Can’t buy them anymore. Easy to make, however.

Why is this object helpful/important in this field of study?

It shows the type of artifacts that were used by people in the 18th century through to the 20th century to understand curved surfaces.

How does the research related to this object affect me or why is it important to the public? 

The world is not flat! It’s through the use of objects such as the spherical chalkboard that scientists and ordinary citizens came to learn about how properties differ on curved rather than flat surfaces. The spherical chalkboard allowed for different conjectures to be explored that couldn’t be technically done in any other way at the time.

Was this object invented in Ontario, or has its use helped with an Ontario research breakthrough?

Not invented in Ontario. I have an undergraduate degree in mathematics with a focus in geometry and I never encountered it in my studies. I found this one in the trash. The person throwing it away didn’t know what it was but I had seen a picture of one and knew immediately what it was. Apparently, they vintage spherical chalkboards are very expensive!

Why is this relevant to all Ontarians?

It’s just purely interesting. However, it can still be a useful way to have young children visualize and conceptualize about the globe. In fact, globes are still used – but the main topical features are always printed on them.

Interesting facts, statistics or stories about this object?

First one was developed at Harvard in 1757. Some more contemporary versions have been developed and sold – mostly as decorations (Pottery Barn and Anthropology). Not generally used for learning anymore. See: