Lab, Ecology, Chemistry, Electricity, and Astronomy Review

The Scientific Method and Lab Safety

• Definition of the Scientific Method: A set of steps to follow in order to properly perform a science experiment.
• Steps of the Scientific Method:
  • Step 1: Make an Observation: Noticing something in the natural world.
  • Step 2: Formulate a Question: A good scientific question is testable and compares two things. The standard format is: "What is the effect of [independent variable] on [dependent variable]?"
  • Step 3: Develop a Hypothesis: Make a prediction based on what is known, often referred to as an "educated guess." It is written in the format: "If _____, then ________."
  • Step 4: Design an Experiment:
    • Identify Variables:
      • Independent Variables: The variable changed by the experimenter.
      • Dependent Variable: The variable that changes as a result of the independent variable.
      • Controlled Variables: All other factors that are kept constant so the experiment is accurate.
    • Documentation: Write a list of materials and create a step-by-step procedure.
  • Step 5: Conduct the Experiment: Make observations and gather information or evidence to answer the formulated question.
    • Qualitative Observations: Information that cannot be measured; collected through the senses to describe qualities.
    • Quantitative Observations: Information based on measurements and counting.
  • Step 6: Refine or Alter the Experiment: Repeat as many times as needed to ensure accuracy.
  • Step 7: Analyze the Data: Look for trends in the observations and determine what the data means.
  • Step 8: Draw a Conclusion: State whether the hypothesis was right or wrong and summarize the results.
  • Step 9: Communicate Results: Share findings with the scientific community.
• Measurement: Includes both measured values and exact values.

Ecology and Sustainable Ecosystems

• Sustainability: The ability to meet the needs of today without compromising the needs of future generations.
• Sustainable Ecosystems:
  • Support organisms and can continue to do so in the future.
  • Characterized by being biodiverse.
• Biodiversity: The variation of biological organisms. Higher biodiversity implies a variety of genes and species, contributing to the sustainability of the ecosystem.
  • Three Components of Biodiversity:
    • Diversity of Genes: Examples include the variation between chihuahuas, beagles, and rottweilers.
    • Diversity of Species: Examples include monkeys, dragonflies, and flowers.
    • Diversity of Ecosystems: Examples include Canadian prairies and rainforests.
• Requirements for Sustainable Ecosystems: They provide organisms with a continual food source, clean water, sufficient space, a suitable habitat, and other organisms to interact with. More sustainability leads to healthier ecosystems.
• Permitting and Limiting Factors: Includes pollution, lack of space, lack of food and water, and low biodiversity.
• Extinction: The permanent disappearance of a species of organisms.
• The Biosphere: The area of Earth where water, land, air, and life exist. It is composed of three interacting layers:
  • 1. Atmosphere (Air):
    • Layers of gases surrounding Earth that regulate temperature.
    • Water vapor and carbon dioxide ($CO_2$) absorb sunlight and hold energy as heat.
    • Oxygen ($O_2$) exists in the lower atmosphere to support life.
    • Ozone ($O_3$) exists in the upper atmosphere to protect against UV radiation.
  • 2. Lithosphere: Earth's solid outer layer extending up to $100\,km$ down. It includes soil and is home to microorganisms, plants, animals, and fungi.
  • 3. Hydrosphere: Comprises all water on Earth; $97\%$ of which is salt water. Includes the water cycle.
• Ecosystem Components: Terrestrial or aquatic environments made of two types of components:
  • Abiotic: Non-living elements such as sunlight, temperature, rainfall, climate, lightning, water, and soil conditions.
  • Biotic: Living elements such as bacteria, plants, animals, fungi, and disease.
• Biomes: Large geographical areas with similar climate conditions, vegetation, and organisms. Particular factors include temperature and rainfall. Examples include tundra, taiga, temperate deciduous forest, grassland/prairies, rainforest, and mountain forest/alpine.

Energy and Energy Flow in Ecosystems

• Types of Energy:
  • Radiant Energy: Energy that comes from the sun.
  • Light Energy: Energy seen by humans and absorbed by plants for photosynthesis.
  • Chemical Energy: Energy stored in the bonds of compounds and molecules.
• Producers (Autotrophs): Organisms that create glucose or chemical energy for food from light energy. They do not consume other organisms.
  • Photosynthesis Formula: $6CO_2 + 6H_2O + \text{ATP} \rightarrow C_6H_{12}O_6 + 6O_2$
  • Word Equation: $\text{Carbon Dioxide} + \text{Water} + \text{Sunlight} \rightarrow \text{Glucose} + \text{Oxygen}$
• Consumers (Heterotrophs): Organisms that eat and consume other organisms for energy.
  • Cellular Respiration Formula: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$
  • Word Equation: $\text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon Dioxide} + \text{Water} + \text{Energy (ATP)}$
• Complementary Processes: Photosynthesis and cellular respiration are complementary. Chlorophyll absorbs red and blue light but reflects green. Leaves have increased surface area to capture light and a waxy coating to reduce water loss.
• Trophic Levels: Categorization of organisms based on how they gain energy:
  • 1st Trophic Level: Producers/Autotrophs; make their own food from abiotic factors.
  • 2nd Trophic Level: Primary consumers; herbivores that feed on producers.
  • 3rd Trophic Level: Secondary consumers; carnivores relying on primary consumers.
  • Tertiary Consumers: Next level of larger consumers.
  • Apex Predators: Top of the food chain.
  • Decomposers: Organisms like bacteria, fungi, earthworms, and insects that feed on detritus (biotic waste and dead remains), returning nutrients to the ecosystem.
• Energy Rule: Organisms use $90\%$ of the energy from food to grow and reproduce, leaving only $10\%$ to pass to the next trophic level.
• Pollutants and Bioaccumulation:
  • Bioaccumulation: Slow buildup of chemicals in the bodies of organisms; stored in fatty tissues.
  • Chemical Examples: PCBs (used in paints, plastics, lubricants) and DDT (an insecticide for mosquitoes, now banned).
  • Biomagnification: Consumers at higher trophic levels receive larger doses of accumulated chemicals than those below them.
  • Toxic Metals:
    • Lead: Not safe at any level; causes anemia and reproductive damage.
    • Cadmium: Toxic to earthworms and fish; causes lung disease, cancer, and nervous system damage.
    • Mercury: Bioaccumulates in the brain, heart, and kidneys of animals.
• Keystone Species: Species that greatly affect population numbers and ecosystem health. Amphibians are valuable indicators because they live on both land and water, making them sensitive to chemical changes.
• Bioremediation: Uses living organisms like microbes (bacteria/fungi) to neutralize pollutants.
  • Rhodococcus bacteria: Can biodegrade PCBs.
  • Plants: Used to trap hazardous waste like heavy metals and stabilize the lithosphere.

Chemistry: Particle Theory and Classification of Matter

• Matter: Anything that has mass and takes up space. It is divided into Pure Substances and Mixtures.
• Particle Theory of Matter:
  1. Matter is made of small particles.
  2. There is space between particles.
  3. Particles are constantly moving.
  4. Energy makes particles move.
• Physical and Chemical Properties:
  • Qualitative Physical Properties: State (solid, liquid, gas), Colour, Malleability (beaten into sheets), Ductility (drawn into wires), Magnetism (attraction to magnets).
  • Quantitative Physical Properties: Solubility (dissolving in water), Conductivity (heat/electricity), Viscosity (resistance to flow), Density (mass/volume ratio), Melting/freezing point (temperature).
  • Chemical Properties: Describe a substance's ability to react. Includes Combustibility (reaction with oxygen to produce $CO_2$, water, and energy).
• Physical vs. Chemical Changes:
  • Physical Change: The substance remains the same; usually easy to reverse.
  • Chemical Change: Becomes one or more different substances; difficult to reverse.
• Density and Buoyancy:
  • Density Formula: $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$
  • Buoyant Force: The upward force acting on a submerged object, opposite to gravity.
  • Archimedes Principle: The buoyant force on a submerged object is equal to the weight of the fluid it displaces. (e.g., a large hollow ship hull displaces enough water to create a force that keeps the light ship afloat).

Atomic Structure and the Periodic Table

• Structure of an Atom:
  • Protons ($+$): Found in the nucleus; mass of $1\,amu$.
  • Neutrons ($0$): Found in the nucleus; mass of $1\,amu$.
  • Electrons ($-$): Orbit the nucleus; negligible mass.
• Atomic Calculations:
  • Atomic Number: Equal to the number of protons (or electrons in neutral atoms).
  • Mass Number: $\text{Number of Protons} + \text{Number of Neutrons}$.
  • Number of Neutrons: $\text{Mass Number} - \text{Atomic Number}$.
• Isotopes: Forms of an element with the same number of protons but a different number of neutrons (e.g., $Cl-35$ and $Cl-37$). They share physical and chemical properties.
• The Periodic Table: Organized by Dimitri Mendeleev using element mass. Elements 1-92 are natural; others are synthetic.
  • Structure: Columns are Groups/Families; rows are Periods.
  • Metals vs. Non-metals:
    • Metals: Shiny (lustrous), malleable, high melting point, ductile, good conductors. Mercury ($Hg$) is the only liquid metal at room temp.
    • Non-metals: Dull, brittle, low melting point (mostly gases), poor conductors. Bromine ($Br$) is the only liquid non-metal at room temp.
• Group Characteristics:
  • Group 1: Alkali Metals: 1 valence electron; tend to lose 1 electron. Lustrous silver, most reactive metals (react with water). Reactivity increases down the group.
  • Group 2: Alkaline Earth Metals: 2 valence electrons; tend to lose 2. Less reactive than Group 1; used in fireworks.
  • Groups 3-12: Transition Metals: Form highly colored compounds.
  • Group 17: Halogens: 7 valence electrons; gain 1. Most reactive non-metals; poisonous and corrosive. Reactivity increases up the group.
  • Group 18: Noble Gases: Full valence shell; stable and non-reactive. Odorless, colorless gases.
• Compounds:
  • Covalent (Molecular): Non-metal + Non-metal; electrons are shared.
  • Ionic: Metal + Non-metal; electrons are transferred from metal to non-metal.
• Compound Identification Tests:
  • Crush Test: Ionic (withstands force, gritty powder) vs. Covalent (flexible, like wax).
  • Melting Test: Ionic (very high temperatures) vs. Covalent (low temperatures).
  • Solubility Test: Ionic (dissolves in water) vs. Covalent (often does not).
  • Conductivity Test: Ionic (conducts electricity) vs. Covalent (does not).

Electricity: Static and Current

• Static Electricity: An imbalance of positive and negative charges on an object.
• Law of Electric Charges:
  1. Opposite charges attract.
  2. Like charges repel.
  3. Charged objects attract neutral objects.
• Detection Devices:
  • Pith Ball Electroscope: Charged object attracts a suspended pith ball.
  • Metal Leaf Electroscope: Charged object causes metal leaves on a rod to spread/repel.
• Charging Methods:
  • Friction: Rubbing different materials together creates a static net charge.
  • Contact: Charged object touches a neutral one; electrons jump to balance charge (shock).
  • Induction: Charged object forces electrons in a neutral conductor to move without touching. Results in the opposite charge on the neutral object.
• Electrical Fields: Transmission of force speed of light; intensity depends on charge quantity and diminishes with distance.
• Circuit Components:
  1. Source: Electrical energy.
  2. Conductor: Wire allowing electron flow (e.g., silver is the fastest conductor).
  3. Load: Transforms electrical energy into other forms.
  4. Switch: Opens or closes the circuit.
• Current Electricity Terms and Formulas:
  • Current ($I$): $\text{Amperes (A)}$; $I = \frac{Q}{t}$. Measured by an Ammeter.
  • Potential Difference ($V$): $\text{Volts (V)}$; $V = \frac{E}{Q}$ or $V = IR$. Measured by a Voltmeter.
  • Resistance ($R$): \text{Ohms (\Omega)}; $R = \frac{V}{I}$. Impeded by Resistors.
  • Power ($P$): $\text{Watts (W)}$; $P = VI$ or $P = \frac{E}{t}$.
  • Energy ($E$): $\text{Joules (J)}$; $E = VQ$ or $E = Pt$.
  • Charge ($Q$): $\text{Coulombs (C)}$; $Q = It$.
• Series vs. Parallel Circuits:
  • Series: One path; components in a line. $\text{SASS}$ (Series Amps Stay Same). $R_T = R_1 + R_2 + R_3$.
  • Parallel: Multiple branches. $\text{PVSS}$ (Parallel Voltage Stays Same). $\frac{1}{R_T} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}$.
• Efficiency: $\text{Efficiency} = \frac{\text{Useful Energy Output}}{\text{Total Energy Input}} \times 100\%$
• Current Types:
  • Direct Current (DC): Electrons move in one direction (powered electronics).
  • Alternating Current (AC): Electrons move back and forth (generating stations, long-distance power).

Astronomy and Space Exploration

• Key Definitions:
  • Rotation: Turning of an object on its axis.
  • Revolution: Movement of one object around another.
  • Astronomical Unit (AU): Distance from Sun to Earth ($150 \times 10^6\,km$).
• The Big Bang Theory: Explains universe formation approx. $13.7 \times 10^9\,years$ ago from a hot mass. Matter, energy, space, and time were created.
  • Evidence 1: Universe Expansion: Observed by Edwin Hubble; galaxies move away from the Milky Way.
  • Evidence 2: Cosmic Background Radiation: Detected using radio telescopes; leftover heat from the explosion.
• The Moon: Distance $384,400\,km$; diameter $3,475\,km$ ($1/4$ of Earth). Formed $4.5 \times 10^9\,years$ ago. Gravity is $1/6$ of Earth's.
  • Rotation/Revolution: Takes $27.3\,days$ for both; hence we only see one side.
  • Craters: Sea of Rains, Copernicus, Sea of Serenity, Sea of Tranquility (Apollo landing), Sea of Clouds.
• Eclipses:
  • Solar Eclipse: Moon blocks Sun's light to Earth.
  • Lunar Eclipse: Earth blocks Sun's light to the Moon.
• Hubble's Law: Galaxies recede proportionately to distance. $\text{Age} = \frac{\text{Distance}}{\text{Speed}}$.
• Doppler Shift:
  • Redshift: Receding galaxies shift to the red end of the spectrum.
  • Blueshift: Approaching galaxies shift to the blue end.
• The Sun: Nearest star, $5 \times 10^9\,years$ old. $73\%$ Hydrogen, $25\%$ Helium. Energy from nuclear fusion.
  • Layers: Core, Radiative zone, Convection zone, Photosphere, Chromosphere, Sun spots, Solar flare, Corona.
  • Magnetosphere: Earth's magnetic field protecting from radiation and solar winds (causes Auroras).
• Hertzsprung-Russell (H-R) Diagram: Relates star color, size, and temperature (measured in Kelvins).
  • Red stars = less energy; Blue stars = more mass/energy.
  • Stages: Main Sequence (early), Giants/Supergiants (intermediate), White Dwarfs (late). White dwarfs are hotter than giants.

• Sustainability: The ability to meet the needs of today without compromising the needs of future generations.
• Sustainable Ecosystems:
  • Support organisms and can continue to do so in the future.
  • Characterized by being biodiverse.
• Biodiversity: The variation of biological organisms. Higher biodiversity implies a variety of genes and species, contributing to the sustainability of the ecosystem.
• Three Components of Biodiversity:
  • Diversity of Genes: Examples include the variation between chihuahuas, beagles, and rottweilers.
  • Diversity of Species: Examples include monkeys, dragonflies, and flowers.
  • Diversity of Ecosystems: Examples include Canadian prairies and rainforests.
• Requirements for Sustainable Ecosystems: They provide organisms with a continual food source, clean water, sufficient space, a suitable habitat, and other organisms to interact with. More sustainability leads to healthier ecosystems.
• Permitting and Limiting Factors: Includes pollution, lack of space, lack of food and water, and low biodiversity.
• Extinction: The permanent disappearance of a species of organisms.
• The Biosphere: The area of Earth where water, land, air, and life exist. It is composed of three interacting layers:
  • 1. Atmosphere (Air): Layers of gases surrounding Earth that regulate temperature. Water vapor and carbon dioxide ($CO<em>2$) absorb sunlight and hold energy as heat. Oxygen ($O</em>2$) exists in the lower atmosphere to support life. Ozone ($O_3$) exists in the upper atmosphere to protect against UV radiation.
  • 2. Lithosphere: Earth's solid outer layer extending up to $100 km$ down. It includes soil and is home to microorganisms, plants, animals, and fungi.
  • 3. Hydrosphere: Comprises all water on Earth; 97 ext{%} of which is salt water. Includes the water cycle.
• Ecosystem Components: Terrestrial or aquatic environments made of two types of components:
  • Abiotic: Non-living elements such as sunlight, temperature, rainfall, climate, lightning, water, and soil conditions.
  • Biotic: Living elements such as bacteria, plants, animals, fungi, and disease.
• Biomes: Large geographical areas with similar climate conditions, vegetation, and organisms. Particular factors include temperature and rainfall. Examples include tundra, taiga, temperate deciduous forest, grassland/prairies, rainforest, and mountain forest/alpine.
• Symbiosis Interactions:
  • Mutualism: Both organisms benefit from the interaction (e.g., bees pollinating flowers).
  • Commensalism: One organism benefits while the other is neither helped nor harmed (e.g., barnacles on whales).
  • Parasitism: One organism benefits at the expense of the other (e.g., ticks feeding on mammals).