1.0 Scientific Method

Observation

The action of noticing and describing events or processes in a careful, orderly way.

Hypothesis

A possible answer or educated guess based on observations.

Independent Variable

The variable that you can control in an experiment.

Dependent Variable

The variable that changes as the independent variable changes.

Controlled Variable

Variables that never change during an experiment.

Trials

One run of an experiment, which should be conducted at least three times.

Qualitative Observation

An observation that is not measured by numbers.

Quantitative Observation

An observation that is measured by numbers.

Physical Property

A characteristic of a substance that can be observed without changing the substance.

Chemical Property

A characteristic that can only be observed during a chemical change.

Pure Substance

A substance made up of only one type of particle.

Mixture

A substance made up of at least two different types of particles.

Element

A pure substance that cannot be broken down into simpler substances.

Compound

A substance made up of molecules that contain two or more different elements.

Mechanical Mixture

A mixture in which you can see the different components.

Solution

A uniform mixture of two or more substances.

Physical Change

A change in which the substance remains the same.

Chemical Change

A change that results in the production of one or more new substances.

Density

The mass of a substance divided by its volume.

Boiling Point

The temperature at which a liquid turns into a gas.

Melting Point

The temperature at which a solid turns into a liquid.

Particles

Tiny components that make up all matter and are in constant random motion.

Atomic Number

The number of protons in an atom's nucleus.

Mass Number

The total number of protons and neutrons in an atom.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Proton

A positively charged particle found in an atom's nucleus.

Neutron

A neutrally charged particle found in an atom's nucleus.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Chemical Formula

A representation that indicates the type and number of atoms in a pure substance.

Molecular Compound

A compound that consists of two or more different non-metals.

Ionic Compound

A compound formed between metals and non-metals, made up of charged particles called ions.

Ion

An atom that has lost or gained electrons.

Alkali Metals

Elements in the first column from the left side of the periodic table; highly reactive.

Alkaline Earth Metals

Elements in the second column of the periodic table; shiny and silvery metals.

Noble Gases

Inert gases located in the far right column of the periodic table; do not react chemically.

Halogen

Very reactive elements to the left of noble gases that often form compounds with alkali metals.

Mendeleev

The scientist who organized elements based on increasing mass and similar properties.

Valence Electrons

Electrons in the outermost shell of an atom, crucial for chemical bonding.

Graph

A visual representation used to show patterns in data.

Vicosity

The ability of a substance to flow.

Malleability

The ability of a substance to be hammered into thin sheets.

Ductility

The ability of a substance to be pulled into a thin strand.

Electrical Conductivity

The ability of a substance to conduct electric current.

Brittleness

The tendency of a substance to break easily.

Clue of Physical Change 1

Change in shape or form without producing a new substance.

Clue of Physical Change 2

Change of state; solid to liquid or vice versa.

Clue of Chemical Change 1

Change in color indicating a chemical change.

Clue of Chemical Change 2

Production of gas or bubbles without heat.

Clue of Chemical Change 3

Formation of a new solid (precipitate).

Clue of Chemical Change 4

Change in temperature or light.

High Heat Capacity

The ability of water to absorb a lot of heat before changing temperature.

Boiling Point of Water

The temperature at which water turns into steam.

Freezing Point of Water

The temperature at which water freezes into ice.