8th GRADE PHYSICSMatter, Forces, Energy, Motion and Heat

SECTION 1: MATTER

Important TermsChemistry- The study of the properties of

matter and how matter changes.

Substance- A single kind of matter that is pure and has a specific set of properties.

Mixture-Two or more substances that are mixed together but not chemically combined.Mixtures can be heterogeneous or homogeneous

DESCRIBING MATTERQuestion: What is matter?

Answer: Anything that has mass and takes up space

All matter is composed of atomsAtom- The basic particle from which all elements

are madeElement- A pure substance that cannot be broken

down into other substances by chemical or physical means.

Chemical Bond- The force that holds two atoms together

Molecule- A particle made of two or more atoms bonded together

Compound- A pure substance made of two or more different elements chemically combinedchemical formula- A formula that gives the

elements in a compound and the ratio of atoms

Example: H2O C6H4O2Fe5

COMPOUNDS VS. MOLECULES

Matter has both physical and chemical properties

Properties of MatterPhysical Property

Examples

physical property- A characteristic of a pure substance that can be observed without changing it into another substance Color Size Shape Mass Density Volume Texture

Chemical Property Examples

chemical property- A characteristic of a pure substance that describes its ability to change into a different substance Reactivity pH (is it an acid or a base) Flammability Toxicity Oxidation states Heat of combustion

MEASURING MATTER Tools of Measurement:

Mass: scale or triple beam balanceLength: rulerVolume:

For a regular shaped object use the formula LxWxHFor a irregularly shaped object use water

displacementDensity

D=M/V

Density of a regular shaped object

This block of wood has the following measurements L= 10cm W= 2cm H= 5cm Mass= 50 g

In your notebook, calculate the volume, then find the density. Remember to label the units

Density of an irregularly shaped object

Toy Dinosaur Mass= 2mg Volume= volume with

object- volume without object V=5.8mL-4.8mL= 1mL

What is the density or the toy dinosaur?

D=M/VD=2mg/1mL =

2mg/mL

NOTE: 1mL=1cm3

CHANGES IN MATTER Matter can undergo physical and chemical

changes

Physical Change- A change in a substance that does not change its identityExamples: changing shape, form, state of matter

Chemical Change- A change in which one or more substances combine or break apart to form new substancesExamples: burning, oxidation, combustion,

tarnishing, electrolysis

Chemical Changes

Physical Changes

ENERGY

ENERGY IN MATTER Key Terms:

Kinetic Energy- The energy of matter in motion

Potential Energy- The energy an object has because of its position; also the internal stored energy of an object, such as energy stored in chemical bonds

Forms of EnergyChemical Energy- A form of potential energy

that is stored in chemical bonds between atoms

Electromagnetic Energy- A form of energy that travels through space as waves

Electrical Energy- The energy of electrically charged particles moving from one place to another.

Energy Transformations

WORK

SPEED, ACCELERATION, and VELOCITY

THERMAL ENERGY (HEAT)