Sound and Earth Science

Comprehensive vocabulary flashcards covering the concepts of sound, echo reflection, layers of the Earth, tectonic plates, and continental drift from the lecture notes.

Loudness

A property of sound influenced by vibration magnitude, where stronger vibrations lead to louder sound and smaller vibrations lead to quieter sound.

Pitch

A property of sound determined by vibration rate, where faster vibrations produce higher pitch and slower vibrations produce lower pitch.

Sound Wave

A sound traveling from a source to your ears that originates when an object vibrates.

Speed of Sound in Air

Approximately $343\,\text{m/s}$.

Reflection of Sound

The bouncing back of sound waves from a surface, occurring effectively on large, smooth, flat surfaces like glass, tiles, metal, and smooth concrete.

Echo

A reflected sound produced when a sound wave hits a surface like a wall.

Useful Echoes

Practical uses of sound reflection, including bats locating insects and avoiding obstacles, boats measuring water depth, and medical scans imaging unborn babies.

Unwanted Echoes

Reflections that spoil music recordings or make speech unclear in theatres, prompting recording studios and theatres to design walls that reduce them.

Age of the Earth

Earth is about $4,500\,\text{million years}$ old.

Crust

The outermost layer of the Earth, made of solid rock.

Mantle

The Earth layer below the crust, made of hot molten rock that can flow slowly.

Core

The innermost layer of the Earth, composed mainly of iron and nickel.

Outer Core

The molten (liquid) section of the Earth's core.

Inner Core

The solid section of the Earth's core.

Alfred Wegener

The scientist who suggested that all land on Earth was once joined together.

Continental Drift

The process by which continents slowly moved apart over millions of years, supported by fitting landmass shapes, matching rock types, and matching fossils.

Tectonic Plates

Huge pieces of the Earth's crust (classified as oceanic or continental plates) that move slowly at a rate of about $4\,\text{cm}$ per year.

Geological Change

Changes that happen to the Earth and its crust, caused by moving tectonic plates and occurring mainly at plate boundaries (such as fold mountains, volcanoes, and earthquakes).

Plate Boundary

The place where two tectonic plates meet.

Subduction

The plate movement process where two tectonic plates move together and one plate slides under another.

Plates Moving Apart

The plate movement process where plates move away from each other, causing magma to rise and form new crust.

Plates Sliding Past

The plate interaction where plates rub against each other, causing pressure to build up until sudden movement triggers earthquakes.

Fold Mountains

Mountains formed when plates move together and rocks are squeezed to fold upwards, with examples including the Himalayas and Rocky Mountains.

Loudness

A property of sound where stronger vibrations lead to a louder sound and smaller vibrations lead to a quieter sound.

Pitch

A property of sound determined by vibration rate: faster vibrations create a higher pitch, while slower vibrations create a lower pitch.

Sound Wave

A sound traveling from a source to your ears, which starts when an object vibrates.

Speed of Sound in Air

The velocity at which sound travels through air, which is approximately $343\,\text{m/s}$.

Mediums of Sound Travel

Sound can travel through solids, liquids, and gases, but it cannot travel through a vacuum.

Reflection of Sound

The bouncing back of sound waves from a surface, occurring especially well on large, smooth, flat surfaces like glass, tiles, metal, and smooth concrete.

Echo

A reflected sound that follows the sequence: Sound wave \rightarrow Wall \rightarrow Reflection \rightarrow Echo.

Useful Echoes

Applications of reflected sound used by bats to find insects and avoid obstacles, by boats to measure water depth, and in medical scans to create images of unborn babies.

Unwanted Echoes

Reflections that spoil music recordings or make speech unclear in theatres; recording studios and theatres design walls specifically to reduce them.

Age of the Earth

The Earth is estimated to be about $4,500\text{ million years old}$.

Crust

The outer layer of the Earth, which is made of solid rock.

Mantle

The layer located below the Earth's crust, made of hot molten rock that can flow slowly.

Core

The central part of the Earth, made mainly of iron and nickel.

Outer Core

The molten (liquid) portion of the Earth's core.

Inner Core

The solid innermost portion of the Earth's core.

Alfred Wegener

The scientist who suggested continental drift and proposed that all land was once joined together.

Continental Drift

The process by which continents slowly moved apart over millions of years.

Evidence for Continental Drift

Three key matching facts: continents fit together, similar rocks match, and similar fossils match.

Tectonic Plates

Huge pieces of the Earth's crust (classified as oceanic or continental plates) that move slowly at a rate of about $4\,\text{cm}$ per year.

Geological Change

Changes that happen to the Earth and its crust, caused by moving tectonic plates and occurring mainly at plate boundaries.

Plate Boundary

The place where two tectonic plates meet.

Subduction

The process occurring when tectonic plates move together and one plate slides under another.

Plates Moving Apart

Plate boundary movement where plates move away from each other, allowing magma to rise and form new crust.

Plates Sliding Past

Plate boundary movement where plates rub against each other, causing pressure to build up until sudden movement causes earthquakes.

Fold Mountains

Mountains formed when plates move together and rocks are squeezed and fold upwards; examples include the Himalayas and Rocky Mountains.