Chapter 1-7 Lecture: Matter, Atoms, and Imaging Concepts

Vocabulary flashcards covering key terms from the lecture notes on matter, atoms, and imaging modalities.

Matter

Anything that has volume and mass.

Volume

The space that a substance or object occupies.

Mass (m)

The amount of matter in an object; denoted by m; remains the same regardless of location; used in scientific contexts.

Weight

The gravitational force on an object; equals mass × gravity (g); commonly measured in pounds in daily life.

Gravity (g)

Acceleration due to gravity; the gravitational field strength; used to relate mass and weight.

Air

A mixture of gases (mostly nitrogen and oxygen) surrounding us.

Vacuum

Empty space with little or no matter.

Atom

The basic building block of matter; composed of a nucleus and electrons.

Element

A substance made of only one kind of atom (e.g., gold).

Nucleus

The center of an atom that contains protons and neutrons.

Proton

Positively charged subatomic particle in the nucleus; mass ≈ 1 amu.

Neutron

Electrically neutral subatomic particle in the nucleus; mass ≈ 1 amu.

Electron

Negatively charged subatomic particle that orbits the nucleus; very small mass.

Atomic Mass Unit (amu)

Unit of mass used to express atomic-scale masses (protons, neutrons ≈ 1 amu).

Pure substance

Material with a single element or compound; not a mixture.

Mixture

A combination of two or more substances not chemically bonded.

Gold (Au)

An element; example used to illustrate a pure element.

Mercury (Hg)

A metal that is liquid at room temperature; an example of an element.

Water (H2O)

A compound made of hydrogen and oxygen.

Air is a mixture

Air contains gases such as nitrogen and oxygen, not a pure substance.

Dust

Small particles visible in light and often suspended in air.

Suspension

Particles dispersed in a medium (e.g., dust in air); not dissolved.

X-ray

Electromagnetic waves used to visualize structures beyond the eye’s limits.

Ultrasound

High-frequency sound waves used for imaging inside the body; beyond eye limits.

MRI (Magnetic Resonance Imaging)

Imaging technique using magnetic fields and radio waves to visualize internal structures.

Planetary model

Early atomic model where electrons orbit the nucleus like planets around the Sun.