Exploring Fossils: Molds, Casts, and Imprints

The video tutorial explains the formation and types of fossils, focusing on imprints, molds, and casts. It begins with an introduction to fossil imprints, using dinosaur tracks as an example of how these are formed in wet mud that hardens over time. The tutorial then delves into the formation of mold and cast fossils, describing how a mold is created when an organism decays and leaves a hollow shape in sediment. This is followed by an explanation of how a cast is formed when minerals fill the mold, creating a replica of the original organism. Examples, such as a fossilized fish and a brachiopod, illustrate these concepts.

What type of fossil is created by the mark of a living thing?

• An impression

• A mineral

• A mold

• A cast

How are dinosaur tracks preserved over time?

• By being covered in ice

• By being encased in amber

• By being buried in sand

• By hardening of wet mud into rock

What is left in the sediment when an organism decays?

• A skeleton

• A fossil

• A mold

• A cast

What fills the empty space in a mold to form a cast?

• Air

• Dissolved minerals and sediments

• Lava

• Water

What is a cast in terms of fossil formation?

• A copy of the original organism's shape

• A hollow area left by an organism

• A type of rock

• A type of mineral