States of Matter and Properties

States of Matter

• There are three states of matter: solid, liquid, and gas.
• Particle Theory: matter is made up of particles that are always in motion, attract each other, and have space between them.
• Particle movement increases with temperature.

Pure Substances and Mixtures

• Pure Substances: have a fixed composition, examples include marble, distilled water, hydrogen, and silver.
• Mixtures: have varying compositions, examples include soft drinks, brass, wood, vinegar, air, salt and water, soil, and cereal.

Density of Ice and Wood

• Ice and wood have a density less than 1.0 g/mL, which is why they float on water.

Static Electricity

• Static electricity is the buildup of electric charge on an object.
• Law of Attraction and Repulsion: like charges repel, unlike charges attract.

Electric Circuits

• Electric circuit components include conductors, insulators, and switches.
• Circuit Behavior:
  • Closed switch: current flows, bulbs light.
  • Bulb #2 unscrewed: circuit open, bulbs before it stay lit.
  • Bulb #5 unscrewed: circuit open, all bulbs go out.

Series and Parallel Circuits

• Series circuits have one path, while parallel circuits have multiple paths.
• Household wiring uses parallel circuits for safety.

Resistance Calculation

• Resistance (R) can be calculated using the formula R = V/I (ohms).

Sustainable Ecosystems

• A sustainable ecosystem is a self-sustaining community; examples of unsustainable areas include deforested regions.

Abiotic and Biotic Factors

• Abiotic factors are non-living, such as sunlight and temperature.
• Biotic factors are living, such as plants and animals.

Producer, Consumer, Decomposer

• Producers: plants that make their own food.
• Consumers: animals that obtain energy by consuming other organisms.
• Decomposers: bacteria and fungi that break down organic matter.

Biodiversity

• Natural ecosystems generally have more biodiversity than artificial ones.

Food Web vs. Food Chain

• Food Web: interconnected food chains.
• Food Chain: a linear sequence of who eats whom.

Invasive Species

• Non-native species that cause harm to the ecosystem, such as zebra mussels.

Population Growth Curve and Carrying Capacity

• Population growth curve shows changes over time.
• Carrying capacity is the maximum sustainable population.

Bioaccumulation

• The accumulation of toxins in organisms.

Space Exploration

Motion of Stars Models

• Geocentric model: Earth-centered model.
• Heliocentric model: Sun-centered model (accepted today).

Solar System

• The Solar System consists of eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Terrestrial Planets

• Characteristics of terrestrial planets, such as Mercury: closest to the Sun, no atmosphere.

Meteor Appearance

• Glowing due to friction with the atmosphere.

Galaxy Types

• Spiral galaxies: have arms.
• Elliptical galaxies: oval shape.
• Irregular galaxies: no specific shape.

Astronomical Unit vs. Light-Year

• AU: distance from Earth to the Sun.
• LY: distance light travels in a year.