Scientific Method and Data Interpretation in Experiments

Independent Variable (IV)

What is changed in the experiment

Dependent Variable (DV)

What is measured

Independent Variable (IV)

What is changed in the experiment

Dependent Variable (DV)

What is measured

Controlled Variables

Factors kept the same for fairness

Control Group

The group in an experiment that does not get tested with the independent variable, used for comparison

Hypothesis

An educated guess or prediction that can be tested in an experiment (If... then...)

Validity

How well an experiment is designed to accurately test the relationship of the independent variable and dependant variable

Reliability

How consistent and repeatable the results are

Laboratory Safety

Always wear safety goggles when using chemicals, never eat in the lab, tie up long hairand immediately report any spills or accidents.

Interpreting Data from Graphs

Identify the type of graph (line, bar, dot), Read the axes carefully (check units and labels), Find trends (directly proportional, inversely proportional, no pattern).

Speed =

Distance / Time

Density

Mass / Volume

Force (Newton's Second Law) =

Mass × Acceleration

Energy Efficiency =

(Useful Energy Output / Total Energy Input) × 100

Drawing a Fully Documented Graph

X-Axis - Independent Variable

Y-Axis - Dependent Variable

Common Graph Types

Bar Graph: Used for categories

Line Graph: Used for continuous data

Dot Plot: Used to show the distribution of data

Independent Variable (IV)

What is changed in the experiment

Dependent Variable (DV)

What is measured

Controlled Variables:

Factors kept the same for fairness

Control Group:

The group in an experiment that does not get tested with the independent variable, used for comparison

Solids

Particles tightly packed, vibrate in place, definite shape & volume

Liquids

Particles loosely packed, move around, take shape of container, fixed volume

Gases:

Particles far apart, move freely, no fixed shape or volume

Melting

Solid → Liquid

Freezing

Liquid → Solid

Evaporation

Liquid → Gas

Condensation

Gas → Liquid

Sublimation

Solid → Gas

Deposition

Gas → Solid

Physical Change

No new substance is formed; reversible

Chemical Change

A new substance is formed; irreversible

Elements

Pure substances made of one type of atom

Compounds

Two or more elements chemically bonded

Mixtures

Two or more substances mixed but not chemically bonded

Metals

Conduct electricity, malleable, shiny

Groups

Vertical columns (similar properties)

Periods

Horizontal rows (increasing atomic number)

1st Law (Inertia)

Objects stay at rest or in motion unless acted on by an external force

2nd Law

F = ma (Force = mass × acceleration)

3rd Law (Action-Reaction)

For every action, there is an equal and opposite reaction

Balanced Forces

No movement

Unbalanced Forces

Causes motion

Gravity

Pulls objects toward Earth

Friction

Opposes motion

Air Resistance

Opposes motion in air

Kinetic Energy

Energy of motion

Potential Energy

Stored energy due to position or state

Thermal (Heat) Energy

Energy related to temperature

Chemical Energy

Energy stored in chemical bonds

Gravitational Potential Energy

Energy based on an object's height

Electrical Energy

Energy from moving electrons

Nuclear Energy

Energy stored in the nucleus of an atom

Light (Radiant) Energy

Energy carried by light waves

Sound Energy

Energy carried by sound waves

Conduction

Heat transfer through direct contact (solids)

Convection

Heat transfer in fluids by movement of currents

Radiation

Heat transfer through electromagnetic waves

Efficiency Formula

Efficiency = (Useful Energy Output / Total Energy Input) × 100

Producers

Plants (make their own food via photosynthesis)

Consumers

Animals (eat plants or other animals)

Decomposers

Fungi & bacteria (break down dead material)

Levels of food chain

Primary producers (plants), Primary consumers (herbivores), Secondary consumers (carnivores), Tertiary consumers (top predators)

Deforestation

Loss of habitat due to human civilisation

Pollution

When human waste is left in the enviroment

Climate Change

How the earth is heating as a result of humans

Scientific Report Components

Title, Aim, Hypothesis, Materials, Method, Results, Discussion and Conclusion