Science 7 Term 1

Scientific Model

A representation used to explain and predict phenomena in science.

Types of Models

Conceptual, physical, and mathematical models that scientists use to represent systems.

Steps in Scientific Investigation

1. Ask a question, 2. Conduct background research, 3. Formulate a hypothesis, 4. Conduct experiments, 5. Analyze data, 6. Draw conclusions.

Types of Variables

Independent variables (manipulated), dependent variables (measured), and controlled variables (kept constant).

Matter

Anything that has mass and occupies space.

Mixture

A combination of two or more substances that retain their individual properties.

Compound

A substance formed when two or more elements chemically combine.

Element

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

Temperature Scales

Common temperature scales include Celsius (°C), Fahrenheit (°F), and Kelvin (K).

Rules for Significant Figures

1. All non-zero digits are significant, 2. Zeros between significant digits are significant, 3. Leading zeros are not significant, 4. Trailing zeros are significant only if there is a decimal point.

GRESA

An acronym for 'Given, Result, Equation, Solve, Answer' used in problem-solving.

Solubility

The ability of a substance to dissolve in a solvent, typically expressed in terms of concentration.

Concentration

The amount of a substance per defined space or volume.

Types of Concentration

Includes mass/volume percent, volume/volume percent, and molarity.

Volume/Volume Percent

A concentration unit calculated as (volume of solute/volume of solution) x 100%.

Percent Mass

The mass of the solute divided by the total mass of the solution, expressed as a percentage.

Mass/Volume Percent

A concentration unit calculated as (mass of solute/volume of solution) x 100%.

Microscope

An instrument used to magnify small objects to observe microscopic details.

Parts of Microscope

Includes the eyepiece, objective lenses, stage, diaphragm, and light source.

Types of Microscope

Light microscopes, electron microscopes, and scanning probe microscopes.

Levels of Biological Organization

Hierarchy spanning from atoms to organisms: atoms, molecules, cells, tissues, organs, systems, organisms.

Unicellular Organisms

Living organisms made up of a single cell.

Multicellular Organisms

Living organisms made up of multiple cells that work together to perform various functions, exhibiting complex organization and specialization.

Plant Cell Parts

Include the cell wall, chloroplasts, vacuoles, nucleus, and mitochondria.

Cell Wall

A rigid outer layer that provides structure and support to plant cells, composed mainly of cellulose.

Chloroplasts

Organelles that conduct photosynthesis, converting light energy into chemical energy stored in glucose.

Vacuoles

Large storage organelles in plant cells that hold water, nutrients, and waste products, maintaining turgor pressure.

Nucleus

The control center of the cell that contains genetic material (DNA) and regulates cell activities.

Mitochondria

Organelles that generate energy for the cell through the process of cellular respiration, converting glucose into ATP.