Review for Science Final

transcript

Electromagnetic Waves

Energy is not a substance that has mass and volume.

We know that energy exists because of its effect on matter (the things around us).

Light is a form of electromagnetic energy and creates vibrations in the form of waves.

Physical Properties of Matter

Physical properties can be observed without changing the identity of the substance:

- Color - Smell - Hardness - Luster - Phases of matter

(solid/liquid/gas)

Mass – the amount of matter in an object

If the ice melts, is there still the same amount of mass in the glass?

Volume – the amount of space taken up by an object.

- mL for liquids - cm³ for solids

Density – the amount of mass in a certain volume of material.

- Find the mass- Find the volume- Divide the mass by the

volumeDensity (g/cm³) = mass (g) volume (cm³)

What instruments could be used to find the density of the cube?

Density of liquids: Some liquids float on others forming layers.

Which is denser, karo syrup or vegetable oil?

Physical Changes

A physical change is a change in size, shape or state without forming a new substance.

Physical Changes State of matter: Add heat: particles move faster and spread apart - solid > liquid > gas Take away heat: particles slow down and move closer together - solid < liquid < gas

Elements and Atoms

An element is a substance that cannot be broken down any further into anything simpler.

Atoms are the smallest particle of an element that have the same chemical properties as the element.

Chemical Changes

A chemical change is a change in matter that produces a new substance with different properties from the original.

Rust is iron oxide: iron + oxygen = rust

Chemical Changes

A compound is a chemical combination of two or more substances.

Sugar is composed of the elements: carbon, hydrogen and oxygen

C12H22O11

Carbonic acid is also composed of the elements: carbon, hydrogen and oxygen

DO NOW

Which of the following graphs shows how the temperatures of the two cups of water most likely changed over 30 minutes?

Temperature and Heat:Energy

Energy = the ability to move matter• Any moving object has energy– Molecules– Cars– Balls– Bikes– A swung baseball bat

Moving Molecules Produce Heat

• Molecules move • The average kinetic

energy determines how hot or cold a material is…its temperature.

Two Kinds of energy:Kinetic and Potential

Kinetic Energy

• The energy of any moving object– A speeding roller coaster dropping down a hill.

Potential Energy

• Energy stored in an object or material. – Moving an object upwards against gravity.• A roller coaster climbing up to the next drop.

Potential Energy and Kinetic Energy

• Energy flows between two objects because they have different temperatures.

• Heat is a form of energy.• Energy will flow from a

hotter object to a cooler one and continue to flow until the objects are the same temperature.

Radiation, Conduction and Convection

• Radiation– The transfer of energy by

electromagnetic waves.

• Conduction– The movement of energy

through direct contact.

• Convection– The transfer of energy by

the flow of a liquid or gas.

Electricity and Magnetism

Static Electricity: when electrons move from one place to another and cause a buildup of an electrical charge

Conductor: A material through which electricity flows easily -

metals, water, humans

Insulator: A material through which heat or electricity does not flow easily –

rubber, wood, plastic

Open circuit: a circuit that has a gap, so electrons cannot flow.

Close circuit: a circuit that has no gap, so electrons can flow.

Electricity and Magnetism Magnet: any object that attracts or repels other

magnets, and also attracts metal objects made of iron, cobalt or nickel

Speed and Distance

Average speed = distance ÷ time

3000 m ÷ 15 min = 200m/min

Review for Science Final

Documents