Plumb bob
device · 2600 BC · Ancient world
A weight on a string for checking the vertical.
What it is made of
- Brass plumb bob weight — has part. A heavy cone.
- Rope — has part. A suspension fibre.
Principles and materials it uses
- Universal gravitation — uses. The string hangs vertical.
- Stone — is made of. The bob of a plumb line is stone or copper.
Where it is used
- Egyptian pyramid — is used in. Plumb bobs were used by Egypt’s builders.
- Quadrant — is part of. A plumb line shows the vertical.