Physics - Waves and Electromagnetic Spectrum

Waves and Particle Model

• Transverse Waves move perpendicular to the direction of the wave (e.g., water waves)
• Longitudinal Waves move in the same direction as the energy (e.g., sound waves), including compressions and rarefactions.

Electromagnetic Spectrum

• Radio Waves – communication
• Microwaves – cooking
• Infrared – heat transmission
• Visible Light – (red, orange, yellow, green, blue, indigo, violet)
• Ultraviolet – can cause cancer
• X-rays – medical imaging
• Gamma Rays – highly penetrating, kill cancer cells

Wavelength, Frequency & Speed

• Wavelength—the distance from one trough to another.

Electricity and Energy

• Electricity is measured in watts.
• Energy is measured in joules.
• Pitch is determined by frequency; higher frequency means higher pitch.

Law of Conservation of Energy

• Energy cannot be created or destroyed; it can only be transformed or transferred.

Heat Energy

• Heat moves from a hotter object to a cooler object until both are the same temperature.
• Conduction: Heat transfer between objects in contact.
• Convection: Heat transfer through fluids (liquids or gases).
• Radiation: Heat transfer through space.

Sound and the Ear

• Outer Ear: Pinna collects sound.
• Middle Ear: Ear drum vibrates, ossicles transmit vibrations.
• Inner Ear: Cochlea converts vibrations to electrical signals.
• Process: Sound waves -> ear canal -> eardrum -> ossicles -> cochlea -> auditory nerve -> brain.

Light and the Eye

• Lens: A curved transparent object that bends light.
• Convex Lens: Fat in the middle, skinny on the sides.
• Concave Lens: Skinny in the middle, fat on the sides.
• Converging—moving towards one point.
• Diverging—moving away from one point.

The Eye Structures

• Cornea: Clear part of the sclera.
• Iris: Controls pupil size.
• Lens: Focuses light onto the retina.
• Retina: Contains photoreceptors.
• Optic nerve: Sends impulses to the brain.
• Pupil: Hole in the eye that allows light to enter.
• Sclera: Outside layer of the eye.

Reflection and Refraction

• Reflect: Light bounces off a surface.
• Diffuse Reflection: Light reflects at many different angles.
• Refraction: Light bends as it passes through one medium to another.

The Five Senses

• Touch, taste, smell, sight, hearing.

Senses and Control (Biology)

• Receptors—sensory neurons—coordinators—motor neurons—effectors.
• Stimuli—something that sets off a reaction.
• Effectors—muscles/glands that respond to stimuli.
• Reflex actions—quick responses to stimuli without brain involvement.

Nervous System and Neurons

• Purpose: Detecting and responding to environmental changes.
• Synapse: Connects neurons.
• Neurons: Long cells carrying electrical signals.
• Sensory Neurons: Collect external information.
• Motor Neurons: Transmit messages to effectors.
• Interneurons: Allow communication and perception.

Endocrine System

• Purpose: Transmits messages via chemical signals (hormones).
• Major Glands: Brain, thyroid, adrenal, pancreas, testes, ovaries

Homeostasis

• Keeping the body balanced (temperature, blood levels, pH).
• Negative Feedback Loop: Response to a change in a variable reverses that change.

Male Reproductive System

• Testes - Sperm production.
• Scrotum: Maintains temperature for sperm.
• Epididymis; Tubes that carry sperm to the vas deferens.
• Seminal Vesicles; Adds fluids to the sperm and semen.

Female Reproductive System

• Ovaries - Egg release.
• Fallopian tubes - transport eggs.
• Uterus - Development of the embryo.
• Vagina - Birth canal.

Fertilisation and Pregnancy

• When sperm and egg fuse, forming a zygote.

Labour & Birth

• Dilation
• Expulsion
• Delivery of placenta

Immune System - Line of Defence

• First line: Barriers (skin, mucus membranes).
• Second line: Non-specific responses (inflammation, fever).
• Third line: Targeted immune response (antibodies, lymphocytes).

Nutrition & Disease

• Nutritional diseases: Caused by nutrient deficiencies.
• Infectious diseases: Caused by pathogens.
• Vaccination: Exposure to a less harmful form of pathogen to build immunity.

Asexual and Sexual Reproduction

• Asexual reproduction: Create genetic copies of oneself without another organism.
• Sexual reproduction: Combination of genetic material from two parents.

Periodic Table

• Groups—columns.
• Periods—rows.
• Atomic Number—number of protons.
• Atomic Mass—weight of protons and neutrons.
• Elements grouped by properties.
• Metalloids; Properties between metals and non metals.

Atom Structure

• Electrons orbit the nucleus.
• Protons are positively charged.
• Neutrons have no charge.

Flame Tests

• Identifying metal ions by the color the flame emits.

Reactivity & Stability

• Atom stability—full valence shell.
• Reactivity depends on valence electrons and distance from the nucleus.

Ionic Bonding

• Atoms gaining or losing electrons to form ions (cations and anions).

Compounds & Formulae

• Combining elements in specific ratios.
• Balancing chemical equations, making sure the same number of atoms of each kind appear on both sides of the equation.

Electron Diagrams

• Visual representation of electrons in atoms.
• Lewis dot diagrams—show valence electrons.

Acid-Base Reactions

• pH scale (0-14), neutral pH is 7.
• Acids have hydrogen ions (H+); Bases have hydroxide ions (OH-).
• Neutralization: Acids and bases react to form a salt and water.

Radioactivity

• Half-life: Time for half of a radioactive material to decay.
• Types of radiation: Alpha, beta, gamma.
• Uses of radioactivity: Medicine, research.

Biotic and Abiotic Factors

• Biotic: Living things in an environment.
• Abiotic: Non-living components of an environment.

Ecosystem

• Interactions between biotic and abiotic factors.

Food Chains, Food Webs, and Energy Flows

• Producers, consumers, and decomposers.

The Cycles (e.g., Carbon, Nitrogen, Phosphorus)

• Biogeochemical cycles—the cycling of elements through the Earth.
• Details of each cycle.