Unit 0: Error Book

Caution

一定要睇曬成條題目唔係後果自負

Unit 1: Chemistry

Lewis Diagram

Draws the valance electrons only
The dots are the electrons
The lines are the bonds (2 electrons)
How to draw: ![[snc2d-lewis]]

Naming bonds

Terms

Molecule: 2+ same or different atoms chemically bonded
Compound: 2+ different atoms chemically bonded
Mixture: 2+ molecule not chemically bonded

Diatomic molecule

Hydrogen
Oxygen
Fluorine
Bromine
Iodine
Nitrogen
Chlorine

Covalent bonds

Add prefix to all chemicals
- 1: Mono
- 2: Di
- 3: Tri
- 4: Tetra
- 5: Penta
- 6: Hexa
Less valance electron goes first
Do not add "Mono" to the first element
Add "-ide" to the last element only

Ionic bonds

$\text{X}^{+a}Y^{-b}=\text{X}{b}\text{Y}{a};(a;\text{and};b;\text{is factorized})$
$\text{X}{b}Y{a}=\text{X};(\text{roman: }a);\text{Y-ide};\text{(for transition metal only)}$

Make sure to balance the charges
The $\text{roman};a$ is the charge of $\text{X}$

Polyatomic ions (TRICKY: Practice is the key!)

Assuming $\text{Y}$ is a polyatomic ion

$\text{X}^{+a}\text{Y}^{-b}=\text{X}{b}\text{(Y)}{a};(a;\text{and};b;\text{is factorized})$
$\text{X}{b}\text{Y}{a}=\text{X};(\text{roman: }a);\text{Y};\text{(for transition metal only)}$

Make sure to balance the charges
The $\text{roman};a$ is the charge of $\text{X}$

Chemical reaction

Structure: Reactant + Reactant -> Product

Chemical equation

Write the reactants and products in chemical symbols
If have heat, put "heat" above the arrow
State (only if the question stated)
- Put in brackets after the chemical symbol
- s: solid
- l: liquid
- g: gas
- aq: aqueous

Balancing chemical equation (TRICKY: Practice is the key!)

Conservation of mass: Mass will not be loss during a chemical equation

Write the reactant and product chemical amount
Make sure the polyatomic ions are not separated
Use multiplications and cross-multiply to mix and match
Count the whole table
Rejoin the chemical equation

Word equation

Write the reactants and products in chemical name (remember the rules)
If have heat, put "heat" above the arrow
Put (State)(Name) if the question stated

Conductive water

Water pulls a ion out from the compound
Surround the ion with water
The ion cannot go back to the compound
Creates conductive water

Chemical reaction type

Synthesis

$\text{A}+\text{B}=\text{AB}$
Combined to form larger compound Decomposition
$\text{AB}=\text{A}+\text{B}$
Break to form smaller compound Combustion (exothermic reaction)
Complete: $\text{Fuel}+\text{O}{2}=\text{CO}{2}+\text{H}_{2}\text{O}$
Incomplete: $\text{Fuel}+\text{O}{2}=\text{CO}{2}+\text{H}_{2}\text{O}+\text{CO}$ Neutralization
$\text{H}{a}\text{X}{b};\text{(acid)}+\text{Y}{c}\text{(OH)}{d};\text{(base)}=\text{Salt}+\text{H}_{2}\text{O}$
Make the pH 7 (neutral)
Balance the hydroxide and hydrogen bond
Application: Chemical spill, medicine, agriculture
Spills: Strong + Weak (avoid huge reaction) Single displacement
$\text{A}$ metal: $\text{A}+\text{CD}=\text{AD}+\text{C}$
$\text{A}$ non-metal: $\text{AB}+\text{D}=\text{AD}+\text{B}$
Double displacement but one of the non-metal is gone Double displacement
$\text{AB}+\text{CD}=\text{AD}+\text{CB}$
swap $\text{B}$ with $\text{D}$

Acid

Taste sour
Corrosive
React with metal
Aqueous acid conduct electricity
- A solution (water)'s molecule will collide with the acid
- Hydrogen ions are detached from the acid

Base

Taste bitter
Corrosive
Not reactive with metal
Aqueous base conduct electricity
Slippery

Detect strong base or strong acidity

The strongness of their characteristic
pH color
Strong acids completely ionize (disassociate) in water (hydrogen ions). No acid left.
Strong base completely ionize (disassociate) in water (hydroxide ions). No base left.
Strong acid: Industrial use
Weak acid: Food industry
Strong acid: Strong cleaning
Weak acid: Daily cleaning

Binary acid

Hydrogen + Element
Word: Hydro- + Element + ic + acid
Chem: $\text{H}_{a}\text{X}$

Oxyacid

Hydrogen + Polyatomic ion containing Oxygen
Word (look at the original ion for 'r')
- End in "-ite": polyatomic + -(r)ous + acid
- End in "-ate": polyatomic + -(r)ic + acid
Chem: $\text{H}_{a}\text{X}$

Base name

Word (Polyatomic Ion or Ion) + Hydroxide
Chem: $\text{(X)}_{a}\text{OH}$

Litmus paper

Acid: Red
Neutral: White
Base: Blue

pH Paper

Acid: Red
Neutral: Green
Base: Purple

Acid rain

Cause: Air pollution + water in atmosphere
Change acidity of soil (effect the ecosystem)
pH = 4, all fish die at pH 4

Unit 2: Biology

1. Introduction

Cell

Basic unit of life
Self replicating
Bounded by membrane
May contain organelle
Contain biological molecule (DNA, protein, sugar)

Cell theory

All living things are made of one or more cells
Cells are the functional unit of life
All cells come from pre-existing cells

Cell type

Prokaryotic cell
- Simple
- No nucleus
- No organelles
- May have tail or fur
- E.g. Bacteria
Eukaryote cell
- Complex
- Have nucleus
- Have organelles
- No tail or fur
- E.g. Animal cell, Plant cell, Fungi

Flagellum: Tail with motor, for moving

2. Cell Structure

Organelles

Little "organs" of cells
Bounded by membrane
Specific functions: DNA replication, cell division, waste excretion

Cell wall

Only in [[#Plant cell]] and Bacteria
Protect and form regular shape
Made from cellulose

Cell membrane

Protective layer
Selectively permeable
- In: Food, Oxygen, Water
- Out: Waste

Cytoplasm

Fill the cell
Hold the Organelles
Constantly flowing gelatin

Cytoskeleton

Scaffolding between Cytoplasm
Maintain cell shape
Made of protein

Nucleus

Direct cell activity
Contains DNA (Deoxyribonucleic acid)

Nucleolus

In Nucleus
Produce Ribosomes

Nuclear membrane

Protective layer
Selectively permeable

Nucleoplasm

Fill the nucleus
Store DNA or [[#Chromosome]]

Endoplasmic Reticulum

Network of tubes
Transport materials
Smooth: No Ribosomes
Rough: Have Ribosomes

Ribosomes

Produce protein and RNA
Attach to Endoplasmic Reticulum

Mitochondria

Bean bag wrapping curvy membrane with liquid
Brake sugar -> energy (Cellular respiration)

Golgi apparatus

Tubes with balls hanging around
Package, Modify, and Sort substance

Vacuoles

Sac with liquid
Store Food, Water, Waste
Plant: Big
Animal: Small

Lysosomes

Rare plant
Small round membrane ball
Digestion: Break large substance to small
Protection: Attack foreigners

Chloroplast

Plant cell only
Bean with coin stack
Contain chlorophyll
Photosynthesis machine

Centrioles

Animal cell only
Cylindrical building
Produce [[#Spindle fibers]]

Spindle fibers

Used for mitosis pulling
Made of protein
Produced by [[#Centrioles]]

Plant Cell Diagram

![[snc2d-plantcell]]

Animal Cell Diagram

![[snc2d-animalcell]]

3. Cell Cycle

Cell cycle: A series of event where the cell grows, reproduces, and dies

Mitosis vs Meiosis

Mitosis:
- 2 daughter cells is identical to the parent cell
- Occur in somatic (non-reproductive body cells)
Meiosis: 2 different cell make a new cell
Grow: Mitosis
Repair: Mitosis
Reproduce
- Asexual: Mitosis
- Sexual: Meiosis

Chromosome Structure

![[20241005115434.excalidraw]]

Interphase

G1: [[#Organelles]] duplicate, Normal life functions
S (synthesis): [[#DNA]] replication
G2: Continue growth, Normal life functions
$90%=20%+50%+20%$
Not in Mitosis

Prophase

[[#DNA]] condense: [[#Chromatin]] form [[#Chromatids]] form [[#Chromosome]]
[[#Centrioles]] move to 2 opposite end
[[#Centrioles]] make [[#Spindle fibers]]
[[#Nuclear membrane]] dissolve

Metaphase

[[#Chromosome]] line up in the equator
[[#Spindle fibers]] attach to [[#Centromere]]
Each [[#Centrioles]] is at the 2 opposite end

Anaphase

[[#Spindle fibers]] pulls apart at [[#Centromere]]
[[#Chromosome]] becomes [[#Chromatids]]

Telophase

[[#Chromatids]] decondense to [[#Chromatin]]
New [[#Nuclear membrane]] group the 2 [[#Chromatin]] partition
Cells begin to split [[#Nucleus]] and [[#Organelles]]
- Animal: Contractile ring -> Cleavage furrow -> [[#Cytokinesis]]
- Plant: Vesicles formation -> Fuse to cell wall -> [[#Cytokinesis]]

Cytokinesis

Complete cell splitting
Each daughter cell is identical to parent cell
Not in Mitosis

4. Cancer

Mutation Checkpoints

G1 and S: Organelle duplication
G2 and M: DNA replication
M: Spindle fibers

Gene Mutation

DNA broken (2 adjacent strand bond together)
Cause: UV light, Toxins, Carcinogen
Gene Mutation = Bad protein = Mutated cell
Macrophages: Checkpoints G2 and M can catch it
Group of Mutated cell = [[#Tumor]]

Substance

Tumor Suppressing Protein: p53
Oncoprotein: E6 and E7
Healthy cells
- Tumor Suppressing Protein: Working
- Proto-oncoprotein: Mostly off
Cancer cells
- Tumor Suppressing Protein: Broken
- Oncoprotein: Always on

Tumor

A mass of cells that has not functions
Bengin: No harm, crowding the surrounding
Malignant Tumor ([[#Cancer cells]]): Harmful, Interfere surrounding function
- Metastasis: Cancer cells establish secondary tumor via bloodstream
- It was fun: Our slides

Cancer cells

Mutated DNA + Broken substance + Harmful
Identity: Irregular shaped, Very big multi-nuclei
Irregular shape

Cancer detection

Endoscope: Fiber optic cable see narrow passage
X-Ray: Electromagnetic radiation beam see through (not bones)
Computerized Axial Tomography (CT): Multi-X-Ray scan
Ultrasound: High frequency sound waves reflect soft tissues
Magnetic Resonance Imaging: 3D image by strong magnetic field
Self-examination
Doctor tests and examinations

Cancer treatment

Surgery: Remove cancer cells
Chemotherapy: Slow down growth with drugs
Radiation: Ionizing radiation kill cancer cells
mRNA: Make protein that attack tumors
Biophotonics: Lazer light beam to detect cancer and treat

5. Case Study

HPV

Human Papillomavirus
Transmitted sexually
Virus cause warts, no symptom, or [[#HPV-related Cancer]]

HPV-related Cancer

35% in Cervix (Narrow neck)
35% in Mouth and Throat
4% in Penile (male)
Major cause: Weak immune system, infertility, obesity
Cancer test: Cervical sampling (takes cell sample)

How HPV develop Cancer

Infect Epithelium cells, glandular cells
Takes 10 - 30 years to develop

HPV insert DNA into the nucleus which produce Oncoproteins E6 and E7
E6 and E7 disrupts proofreading process of the cell
E6 and E7 promotes tumor and malfunction (Mutation)
Accumulation of mutation causes Cancer

6. Microscope drawing

Total magnification

$\text{Total}=\text{Ocular}\times \text{Objective}$
Ocular lens: 10x
Objective lens
- Low: 4x
- Medium: 10x
- High: 40x

Rule of Thumb

Amount
1. 2 cells
Tool
1. Pencil
2. Ruler
Label line
1. No arrows
2. Straight
3. Untangled
4. Touch object
5. Right side
6. Visible organelles
Title
1. Cell type
2. Total magnification

7. Specialized Cells

1. Red Blood

![[20241021165018.excalidraw]]

Structure
- Dimple in the middle holds $\text{O}_{2}$
- Hemoglobin picks up $\text{O}_{2}$
- No nucleus
Function
- Carries $\text{O}_{2}$ from lungs to body parts
- Carries $\text{CO}_{2}$ from body to lungs

2. White Blood

![[Drawing 2024-10-21 16.56.47.excalidraw]]

Structure
- Changes it's shape to eat the intruder
- Made from bone marrow
- In the bloodstream
Function
- Part of the Immune System
- Protect our bodies from Sickness and Pathogens
  - Virus, Bacteria, Allergies, Cancer

3. Egg

![[Drawing 2024-10-21 17.07.18.excalidraw]]

Structure
- Cytoplasm contains Yolk (Nutrition) for Embryo
- Carries mother's DNA
Function
- Grow a human baby

4. Sperm

![[Drawing 2024-10-21 17.11.29.excalidraw]]

Structure
- Long tail to swim
- Scissor enzymes to get into Egg
- Carries father's DNA
Function
- Complete the mother's genetic information

5. Skeletal muscle

![[Drawing 2024-10-21 17.14.38.excalidraw]]

Structure
- Muscle fiber strands arranged in bundles
- Looks like large cables
Function
- Contract to make bones move
- Move your bones and organs around

6. Skin

![[Drawing 2024-10-21 17.18.36.excalidraw]]

Structure
- Layers of flattened cells
- Fit tightly
Function
- Protect cells in the body
- Reduce water loss

7. Fat

![[Drawing 2024-10-21 17.22.41.excalidraw]]

Structure
- Large Vacuoles store fat
- Small Nucleus at the top
Function
- Heat insulation
- Body cushioning

8. Bone

![[Drawing 2024-10-21 17.27.37.excalidraw]]

Structure
- Compact cells located on the surface
- Spider web like cell in the middle bone
Function
- Support body organs
- Osteoblasts: Build bones by Calcium
- Osteoclasts: Break bones --> reabsorb Calcium to repair

9. Nerve

![[Drawing 2024-10-21 17.44.39.excalidraw]]

Structure
- Very long cells
- Branches to communicate with other nerve cells
- The bulbs are fat to insulate and increase rate of information
Function
- Carry nerve impulses

10. Ciliated Epithelial

![[Drawing 2024-10-21 17.52.35.excalidraw]]

Structure
- Line in lung
- Cilia: Tiny hair
Function
- Prevent lung damage
- Cilia grip and trap dust and bacteria

11. Root Hair

![[Drawing 2024-10-21 17.58.41.excalidraw]]

Structure
- Large surface area from roots
- Large vacuole for storing water
- No chloroplast
Function
- Absorb water and minerals from soil
- Pass water and minerals to the plant

8. Introduction Organs

Hierarchy of Life

Cell
Tissue
Organ
Organ System
Organism

Tissue Type

1. Epithelial

Sheets of tightly packed cells
Layers
- One: Simple epithelium
- Multi: Stratified epithelium
Regular cell shape
- Cuboidal
- Squamous
- Columnar

2. Connective

Support and Protection
Example: Bone, Cartilage

3. Muscle

Contracting only, move bones
Types
- Skeletal: Contract to move bones
- Smooth: Digestive involuntary
- Cardiac: Involuntary endurance for heart

4. Nervous

Communicate with electrical signals
Have webs that connect to other cells

9. Organs

1. Musculoskeletal

![[Drawing 2024-10-31 21.24.27.excalidraw]]

2. Digestive

![[Drawing 2024-10-31 21.28.11.excalidraw]]

3. Nerve

![[Drawing 2024-10-31 21.35.44.excalidraw]]

4. Respiratory

![[Drawing 2024-10-31 21.44.27.excalidraw]]

5. Circulatory

![[Drawing 2024-11-01 09.25.06.excalidraw]]

6. Reproductive (M and F)

Unit 3: Physics

1. Introduction

Light

[[#Electromagnetic Wave]] $=$ Energy
Energy transmitted through [[#Radiation]] ([[#Medium]] is NOT required)
$C=3\times 10^8;\text{ms}^{-1}$ (Significantly faster than sound)

Medium

Physical carrier for transmitting energy

Visible Light

Small part of the [[#Electromagnetic Spectrum]]
Detectable by the human eye

Radiation

Energy transmission that does not require a [[#Medium]]

Electromagnetic Wave

A Wave: Electric $+$ Magnetic
$\uparrow$ Frequency $=$ $\downarrow$ Wave Length
$\uparrow$ Amplitude $=$ $\uparrow$ Energy
[[#Light]] ![[Drawing 2024-11-11 14.00.58.excalidraw]]

Electromagnetic Spectrum

![[snc2d-]]

Electromagnetic Wave Examples

Astronomy: Analyze data about the universe

Waves	Examples
Radio	Phone, Radar
Microwave	Microwaves
Infrared	Remote, Heat detection
Visible	Screen, Lighting
Ultraviolet	Disinfection
X-Ray	Medical scan, Security scan
Gamma Ray	Cancer treatment

Visible Light Colors

ROY G BIV

Red ($\uparrow$ wavelength, $\downarrow$ frequency)
Orange
Yellow
Green
Blue
Indigo
Violet ($\downarrow$ wavelength, $\uparrow$ frequency)

2. Light production

Luminous

Produce light

Non-Luminous

Reflect light

Incandescent

Heating a metal filament using Electricity
High temperature metal glow
Very Inefficient: $5%$ Light energy

Electric Discharge

Pass Electricity through Gas
Example: Noble Gas $+$ Electricity $=$ Light (Electrons hanging around)

Fluorescence

Absorb UV, Instant visible light release
Example: Fluorescene Light Bulb
1. Mercury Vapour $+$ Electricity $=$ UV Light
2. UV Light $+$ Fluorescent $=$ Visible Light

Phosphorescence

Absorb UV, Slow visible light release
Example: The glowing clocks

Chemiluminescence

Chemical Reaction
Minimal heat release
Example: Glow stick, Luminol (React with iron in blood)

Bioluminescence

Chemical Reaction
Living Organism
Minimal heat release
Examples
1. Fireflies: Luciferin $+$ Oxygen $+$ Luciferase (enzyme) $\to$ Photons (Light) $+$ Inactive Oxyluciferin (Oxidized)
2. Angular fish: A sack of glowing bacteria
3. Jelly fish: Enzymes like fireflies

Triboluminescence

Friction
Crush, Scratch, Ripped, Rubbed
Example: Quartz crystal, Diamond

Light Emitting Diode (LED)

Semiconductor $+$ Electricity
Small heat release
Very efficient

3. Reflection

Rays

Light traveling in a straight line without obstacles
Indicated with straight lines and one arrow

Geometric Optics

Use light rays to determine how light behaves when it strikes an object

Reflection

Bouncing back of light from a surface

Drawing conventions

![[20241113195843.excalidraw]]

Laws of Reflection

$\theta_{i}=\theta_{r}$ , Angle of Incident $=$ Angle of Reflection
Incident Ray, Reflected Ray and Normal lies of the same plane

1. Specular Reflection

Smooth surface
Regular reflection ![[20241113200759.excalidraw]]

2. Diffuse Reflection

Irregular surface
Irregular reflection, Scattered reflected rays ![[20241113201428.excalidraw]]

4. Mirrors

1. Mirror |

![[20241123144928.excalidraw]]

Size: Same
Altit: Laterally Inverted
Loc: Behind mirror
Typ: Virtual

2. Concave mirror )

![[20241123150221.excalidraw]]

Principal Axis ($\text{PA}$): Through $\text{C}$, like the radius of the circle
Center of curvature ($\text{C}$): The center of the curving side
Focus ($\text{F}$): All parallel to $\text{PA}$ rays converge to $\text{F}$
Vertex ($\text{V}$): The end of $\text{PA}$
Converging
Going through $\text{C}$: Rebouce
Going through $\text{V}$: Same angle
Going through $\text{F}$: Make parallel

1. > C

![[20241123151958.excalidraw]]

Size: Smaller
Altit: Laterally Inverted
Loc: | FC |
Typ: Real

2. @ C

![[20241123151741.excalidraw]]

Size: Same
Altit: Laterally Inverted
Loc: @C
Typ: Real

3. | FC |

![[20241123162410.excalidraw]]

Size: Bigger
Altit: Laterally Inverted
Loc: >C
Typ: Real

4. @ F

![[20241123162818.excalidraw]]

No Image
Parallel reflected rays

5. < F

![[20241123163302.excalidraw]]

Size: Bigger
Altit: Upright
Loc: Behind mirror
Typ: Virtual

Examples

Flashlight: Produce parallel beam
Telescope: Focusing distant source
Cosmetic mirror: Enlarge images

3. Convex mirror (

![[20241123170548.excalidraw]]

Principal Axis ($\text{PA}$): Through $\text{C}$, like the radius of the circle
Center of curvature ($\text{C}$): The center of the curving side
Focus ($\text{F}$): All parallel to $\text{PA}$ rays converge to $\text{F}$
Vertex ($\text{V}$): The end of $\text{PA}$
Diverging
Going through $\text{C}$: Rebouce
Going through $\text{V}$: Same angle
Going through $\text{F}$: Make parallel

1. In front of mirror

![[20241123171338.excalidraw]]

Size: Smaller
Altit: Upright
Loc: Behind mirror
Typ: Virtual

Examples

Security mirrors: Wide view angle
Side-view car mirrors: Wide view angle
Automatic Teller Machine security mirror: Wide view angle

5. Refraction

Opacity

1. Translucent

$100%$ light pass through

2. Transparent

$x%$ light pass through

3. Opaque

$0%$ light pass through

Refraction

The bending of light
From one medium to another
Only occur in non-opaque mediums
Speed change --> Cause direction change

Refractive Index

$n_{k}=\frac{3.00\times10^{8};ms^{-1}}{k;ms^{-1}}$
Ration between
- Speed of light (c) in vacuum
- Speed of light in a medium

Laws of Refraction

![[20241123174122.excalidraw]]

$n_{i}\sin\theta_{i}=n_{R}\sin\theta_{R}$
$n_{k}=\frac{3.00\times10^{8};ms^{-1}}{k;ms^{-1}}$
Fast to Slow: Bend towards normal
Slow to Fast: Bend away normal
If $\theta_{i}=90^{\text{o}}$, then $\theta_{r}=90^{\text{o}}$

Dispersion

Different light energy bend differently
More energy $=$ Bend more (NON VACUUM ONLY)
White light disperse to a range of colored light

Total Internal Reflection

Critical angle
- If incident ray is bigger
- Total internal reflection occurs
$\theta_{c}=\sin^{-1}{(\frac{n_{R}}{n_{{i}}})}$
- $n_{i}\geq n_{R}$
- Slow --> Fast

Examples of Total Internal Reflection

Fiber optic cables: Bouncing light to high speed communication
Triangular prisms: Shift image position in binoculars

6. Lenses

![[20241123213539.excalidraw]]

Principal Axis ($\text{PA}$): Through $\text{O}$
Vertical Axis ($\text{VA}$): Through $\text{O}$
Optical Center ($\text{O}$): The absolute middle of the lens
Focus ($\text{F}$): All parallel lines converge

1. Converging lens ()

1. > 2F

![[20241123214144.excalidraw]]

Size: Smaller
Altit: Laterally Inverted
Loc: |F2F|
Typ: Real

2. @ 2F

![[20241123211250.excalidraw]]

Size: Same
Altit: Laterally Inverted
Loc: @2F
Typ: Real

3. | F2F |

![[20241123214306.excalidraw]]

Size: Bigger
Altit: Laterally Inverted
Loc: >2F
Typ: Real

4. @ F

![[20241123214437.excalidraw]]

No image
Parallel reflected rays

5. < F

![[20241123214557.excalidraw]]

Size: Bigger
Altit: Upright
Loc: In front of lens
Typ: Virtual

2. Diverging lens )(

![[20241123223654.excalidraw]]

Principal Axis ($\text{PA}$): Through $\text{O}$
Vertical Axis ($\text{VA}$): Through $\text{O}$
Optical Center ($\text{O}$): The absolute middle of the lens
Focus ($\text{F}$): All parallel lines diverge

![[20241123215726.excalidraw]]

Size: Smaller
Altit: Upright
Loc: In front of lens
Typ: Virtual

7. Eyes

1. Eye structure

![[20241124113114.excalidraw]]

Iris

Light control ring in front of the [[#pupil]]
Open: Let more light
Close: Let less light

Pupil

The hole that light enters
Behind the [[#iris]]

Cornea

Transparent bulge (1st lens)
Converging lens --> Focus light
Light refraction

Lens

Clear flexible structure (2nd lens)
Flexible converging lens --> Focus and adjust light
Change shape --> Adjust light focus
Change shape using [[#ciliary muscle]]

Ciliary muscle

Relax and Contract
Accommodation: Adjust the [[#lens]]

Retina

Light sensitive cells
Image focused on retina using [[#lens]] and [[#cornea]]
Transfer electrical signals through [[#optic nerve]]

Optic nerve

Send electric signals towards the brain
Receive electric signals from [[#retina]]
Blind spot: The optic nerve entrance

2. Eye focusing problems

1. Hyperopia (X Near)

Cannot see near objects
Object focused behind the [[#retina]]
Eye ball is too short --> Distance between lens and retina too small
Correction: Converging lens

2. Myopia (X Far)

Cannot see far objects
Object focused in front of the [[#retina]]
Eye ball is too long --> Distance between lens and retina too large
Correction: Diverging lens

3. Presbyopia (X Near + Inflexible)

Cannot see near objects
Object focused behind the [[#retina]]
Inflexible [[#lens]] --> Cannot tweak the light focus
Correction: Converging lens

LASIK Surgery

Slice a flap out of your [[#cornea]]
Use laser to vaporize and carve a curve
Close the flap, heals on it's own

Unit 4: Earth and Space

1. Climate Change

Long-term changes in Earth's average temperature and weather patterns.
Cause
- Human: Fossil Fuels, Deforestation, Industrial Activity, Transportation
- Natural: Volcanic Eruptions
How much has changed
- 1.1 since 1900s
- Melting ice caps
- Rising sea level
- Extreme weather
- Ocean acidification

2. Weather VS Climate

Weather	Climate
Changes in atmospheric conditions over a small period of time	Average change in atmospheric conditions over long period of time
Wind, Temperature, Precipitation	Tropical, Dry, Arctic

3. Climate change factor

Distance from the equator (latitude)
Presence of large bodies of water
Presence of ocean
Air current
Land formations
Height above sea level (altitude)

4. Climate Projection

Scientific forcast
- Computer models
- Human observations
- Past results

5. Heat Transfer

Conduction: By contact
Convection: By fluid
Radiation: Travels as waves

6. Sun Light

Electromagnetic spectrum
1. Infrared (heat)
2. Visible light
3. Ultraviolet
Heat
- Infrared Radiation is converted to thermal energy
- Thermal Energy raises the temperature
- Earth temp $=$ Infrared Radiation
- Note: The Heat comes from the ground
Temperature
- Density of the ray
  - Middle: Less distributed area
  - Front and Back: Sloped -> More distributed area
- Earth is titled

7. Sun Light distribution

$70%$ absorbed
$30%$ reflected
$<1%$ photosynthesis

8. Climate Zones

Polar Zones
Temperate Zones
Tropical Zones
- Tropic of Cancer: up
- Tropic of Capricorn: down
- The sun can be directly overhead

2. Climate System

1. Sphere systems

Interact with each other
Powered by the sun

Atmosphere: Gas surrounding the Earth
1. Air content
  - $78%;\ce{N_{2}}$
  - $21%;\ce{O_{2}}$
  - $0.9%;\ce{Ar}$
  - $0.1%$ Other
    - $0.04%;\ce{CO_{2}}$
    - $0.06%;\ce{CH_{4}, N_{2}O, O_{3}, Ne, H_{2}, He}$
  - Var: $\ce{H_{2}O}$ and Dust
- Altitude
  - High altitude is colder
    1. Heat emits from the ground
    2. Thin air holds less moisture and heat
- Heat sink
  - Coriolis effect
    - Original: Wind goes to the poles
    - Earth's rotation make the wind go sideways
  - Prevailing winds
    - Warm air rise: Low pressure
    - Cold air sink: High pressure
    - Creates a wind loop
Hydrosphere: All water in all state
- Water Cycle
- Evaporation: Cooling effect
- Condensation: Heating effect
- Slow heating and cooling
  - Heat capacity
  - NOT Heat conductivity
- Heat sink
  - Heat reservoir: Ocean
  - Warm in winter: Slowly release heat
  - Cool in summer: Slowly heating up
- Ocean current
  - Cold water sink (dense)
  - Hot water rise (less dense)
  - Creates a current loop
- Cold $=$ Dense
- Salty $=$ Dense
Lithosphere: Earth's crust and land
- Land formation (mountains)
  - Windward (wet): Clouds retained
  - Leeward (dry): Clouds blocked
Biosphere: Living organisms
- Plants: $\ce{CO_{2}}\to\ce{O_{2}}$
- Animals: $\ce{O_{2}}\to\ce{CO_{2}}$

2. Chemistry

Electronegativity

Electron attractability
Right corner of periodic table: Highest

Polarity

Electric charge distribution

Polar bonds

Non Polar Bond: Electron (charge) is equal in all atoms
Polar Covalent Bond: Electron (charge) is uneven ([[#Electronegativity]])
Ionic Bond: The atoms are distinct

3. Greenhouse effect

The atmosphere contain Greenhouse Gas
Greenhouse gas and clouds absorb and reemit IR (heat)
Heat trapper $=$ Keep the Earth warm
Greenhouse Gas
- Measured in PPM $= 1\text{mgL}^{-1}$
- $\ce{H_{2}O}$: Water vapor
  - Positive feed back loop
    1. $\uparrow$ vapor -> $\uparrow$ heat trapped
    2. $\uparrow$ heat trapped -> $\uparrow$ temperature
    3. $\uparrow$ temperature -> $\uparrow$ vapor
- $\ce{CO_{2}}$: Carbon dioxide
  - Pumped by the industrial age ($280$ppm -> $420$ppm)
  - Carbon Sink (Offset $\ce{CO_{2}}$)
    - $\ce{CO_{2}}$ absorbing reservoir
    - Forest, Phytoplankton
- $\ce{CH_{4}}$: Methane
  - Super powerful
  - Produced by
    1. Plant decomposition
    2. Animal digestion
- $\ce{N_{2}O}$: Nitrous Oxide
  - Hyper powerful
  - Produced by
    1. Bacteria in soil
    2. Industrial activity
- $\ce{O_{3}}$: Ozone
  - Stratosphere: Absorb $\ce{UVA}+\ce{UVB}$
  - Troposhere: $\ce{NO}+\ce{NO_{2}}+\ce{VOCs}+\ce{UV}\to$ Smog ($\ce{O_{3}}+\text{Toxins}$)
    - Come from cars
    - Smog: Floggy air pollution
How does it work?
1. Greenhouse gases are Polar Covalent Bonds
2. Uneven $=$ Lopsided charges
3. Lopsided $=$ Stretch, Bend, Twist on their own
4. Wiggles $=$ Absorb wide range of wavelengths
  1. Absorb Infrared (heat)
  2. Reemit back to the earth

4. Thermohaline Circulation

Driven by convection (density)
- Thermo $=$ Heat
- Haline $=$ Salt
Hot water rise + Cold water sink --> Water movement
The giant global conveyor belt
- Gyre: The infinite loop
- More hot water --> Speed up ice cap melting
Nutrient, Oxygen, Heat, and Water flow
More: Messy notes

3. Variations

1. Long term Variations

Plate tectonics

Moving continents change air + water circulation
Change landform (Mountain windward)
Change ocean current pattern

Ice age

Earth's climate alternate between Cold and Hot
Change factors
1. Orbit Eccentricity: Earth's ellipticalness
2. Axial Tilt: Tilt angle affect season intensity
3. Precession: Earth wobbles as it spins

2. Short term Variations

Volcanic Eruption

$\ce{SO_{2}}$ Cloud screen blocks sunlight
Cool climate temporarily (like nuclear winters)
Increase precipitation (more dust)

El Nino

Large wind and ocean current
Bring warm pacific wind to south america
Change global weather patterns

Water Vapor Loop

Higher temps → More evaporation → More vapor → Higher temps
Negative loop: Higher clouds reflect sunlight (stabilize)

Albedo effect

Ice reflects sunlight
Positive loop: Less ice -> Less reflection -> Warmer -> Less ice

3. Climate history

Tree Rings

Thick ring $=$ Wet years
Thin ring $=$ Dry years

Ice Cores

Layer by layer
- Atmosphere compounds
- Weather pattern
- Temperature pattern
- Volcanic activity

Fossils

Animals revel paleoclimate
Animals can only live in specific climate

4. Climate Change Evidence

1. Rising Temperature

Average global temperature increase since 1880s
11 of the last 12 years warmest record

2. Melting Glaciers and Ice

Significant glacier reduction
Significant ice sheet reduction

3. Rising sea level

Cause
- Melting Glaciers and Ice
- Thermal expansion
- Decreased groundwater level

4. Increase severe weather

More severe weather
- Hotter temperature
Heat waves and Hurricane intensity

5. Change precipitation patterns

6. Changing seaons

Less winter of course
More intense summers

7. Change in ecosystem

Caused by climate change
Animals can only live in very specific conditions

5. Greenhouse Gases

1. Carbon Cycle

![[20241210183230.excalidraw]]

2. Anthropogenic Source

Anthropogen

Greenhouse gas by human influence
$\ce{CO_{2}}$: Carbon Dioxide
$\ce{CH_{4}}$: Methane
$\ce{N_{2}O}$: Nitrous Oxide

Gas Sinks

Healthy forest
- Plants and Trees
- Rocks and Soils
Ocean
- Water
- Phytoplankton ($\ce{CO_{2}}$ only)

Carbon Source

Energy production
- Burning fossil fuels
- Extracting fossil fuels
- Transportation
Industrial activities
Burning biomass
Livestock and Farming
Deforestation
- Deforestation
- Decaying forests
- Forest fire

Methane Source

Energy production
- Burning fossil fuels
- Extracting fossil fuels
- Transportation
Industrial activities
Burning biomass
Livestock and Farming
Melting permafrost
Wetland (by microbes)

Nitrous Oxide Source

Energy production
- Burning fossil fuels
- Extracting fossil fuels
- Transportation
Industrial activities
Burning biomass
Livestock and Farming
Waste and Sewage

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Unit 0: Error Book

Unit 1: Chemistry

Lewis Diagram

Naming bonds

Terms

Diatomic molecule

Covalent bonds

Ionic bonds

Polyatomic ions (TRICKY: Practice is the key!)

Chemical reaction

Chemical equation

Balancing chemical equation (TRICKY: Practice is the key!)

Word equation

Conductive water

Chemical reaction type

Acid

Base

Detect strong base or strong acidity

Binary acid

Oxyacid

Base name

Litmus paper

pH Paper

Acid rain

Unit 2: Biology

1. Introduction

Cell

Cell theory

Cell type

2. Cell Structure

Organelles

Cell wall

Cell membrane

Cytoplasm

Cytoskeleton

Nucleus

Nucleolus

Nuclear membrane

Nucleoplasm

Endoplasmic Reticulum

Ribosomes

Mitochondria

Golgi apparatus

Vacuoles

Lysosomes

Chloroplast

Centrioles

Spindle fibers

Plant Cell Diagram

Animal Cell Diagram

3. Cell Cycle

Mitosis vs Meiosis

Chromosome Structure

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

4. Cancer

Mutation Checkpoints

Gene Mutation

Substance

Tumor

Cancer cells

Cancer detection

Cancer treatment

5. Case Study

HPV

HPV-related Cancer

How HPV develop Cancer

6. Microscope drawing

Total magnification

Rule of Thumb