Rocks and Rocky Matter Quiz

Rocks and Rocky Matter

• People used readily available materials like rocks to create tools before advanced technology
• A Hoko knife, a model of an original knife, was made of a small, sharp stone tied to a wooden handle.
• The original knife was found near the Hoko River in western Washington.
• Archaeologists believe people used the knife about 2,700 years ago to cut fish.

Types of Rocks

• Rocks are classified into three main types: Igneous, Sedimentary, and Metamorphic, based on how they form.
• Igneous rocks form when magma (molten rock) cools and hardens, either above or below the Earth's surface.
  • Coarse-grained igneous rocks form when magma cools slowly. Examples include granite.
  • Fine-grained igneous rocks form when lava cools quickly. Basalt is an example.
• Sedimentary rocks form from sediments (small pieces of rock) that are pressed and cemented together in layers.
  • Sedimentary rocks can be fine-grained (like shale) or coarse-grained (like sandstone).
  • Some are made from the remains of animals and plants (e.g., limestone).
• Metamorphic rocks form when igneous or sedimentary rocks are changed by heat and pressure.
  • Metamorphic rocks can have a "foliated" texture (bands) or not. Examples include slate and marble.

Rocks in Singapore

• Singapore's rocks are mainly igneous (like granite), found in the central part.
• Sedimentary rocks are found in the east and west parts of the island.
• A small area of metamorphic rock is in Pulau Tekong.
• Bukit Timah Granite Formation is a significant area of granite in Singapore.

The Rock Cycle

• Rocks constantly change from one type to another in a continuous cycle.
• Rocks are broken down (weathered and eroded), turned into sediments, and then compressed to form sedimentary rocks.
• Intense heat and pressure change rocks into metamorphic rocks.
• Metamorphic rocks can melt into magma (under intense heat), which leads to igneous rocks.