Sci of Life - Module 1 Physics in Daily Life PDF
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Harvard University
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This document introduces the topic of physics in daily life, covering the Milky Way galaxy, units of measurement, and Earth's evolution. It details significant events such as the formation of the solar system and the evolution of life on Earth.
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**IMPORTANT** **Module 1: Physics in Daily Life** - Milky Way - A spiral galaxy - Comprises approx. 100 billion stars (sun is one of those) - Consists of a central bulge and 4 major arms; - Sun is located near the Orion arm - Diameter: about 100,000 light-years - The Sun is abo...
**IMPORTANT** **Module 1: Physics in Daily Life** - Milky Way - A spiral galaxy - Comprises approx. 100 billion stars (sun is one of those) - Consists of a central bulge and 4 major arms; - Sun is located near the Orion arm - Diameter: about 100,000 light-years - The Sun is about 28,000 light-years from the Galactic Center - Speed of light is about 300,000 km/sec - Andromeda Galaxy: the nearest major galaxy to the Milky Way - Units of Measurement - Astronomical Unit (AU/au) - Light-year/light year - Earth Evolution / Birth of Solar System - 4.5 billion years ago: - Hydrogen, Sulfide, Methane, Carbon Dioxide made up the first atmosphere - 3.8 billion years ago: planet cooled enough for water to condensate and become liquid - 3.7 billion years ago: life began (microscopic organisms) - 3.3 billion years ago: craton (lands rose from the ocean), (the first one was named Vaalbara - even smaller than Australia) - 2.4 billion years ago: cyanobacteria evolved (became our first photosynthesizers - oxygen producers) - Ice age: Low level of carbon dioxide - 1.1 billion years ago: atmosphere was changing, continents were moving (broke up then formed a supercontinent called Rodinia) - Rodinia broke apart and formed another supercontinent called Pannotia - 540-485 million years ago: explosion of new life called the Cambrian Explosion (animals evolved during this period had hard body parts like shells or spines) - 440 million years ago: first mass extinction event called Ordovician-Silurian Extinction (climate and ocean temperature changed dramatically) - 420-350 million years ago: first trees, first animals making their way to land - 250 million years ago: covered by vast supercontinent called Pangea, greatest mass extinction called the Great Dying (greenhouse gas and global warming wiped out 90% life on earth) - 240-230 million years ago: first dinosaurs (ruled for 150 million years), Pangea broke up and form the continents we know today - 66 million years ago: asteroids slammed → climate change → dinosaurs extinction - 6 million years ago: Sahelanthropus (earliest known humans) - 4 million years ago: early humans began to walk upright - 5 million years ago: developed tools (used to break things) - 800,000 years ago: discovered fire → cook foods, warm up, interact with each other and discover the world - 40,000-15,000 years ago: all humans species went extinct except homosapiens - 10,000 years ago: began farming - 250 years ago: industrial revolution (major technological, socioeconomics, cultural transformations - farm-based societies became more industrialized) - 1804: reached one billion people - Gravity - An attractive force between all objects with mass - Keeps us from falling off the earth, keeps the earth in orbit around the sun, cause the sun, planets, and moon to form - [\$F = G\\frac{m\_{1}m\_{2}}{r\^{2}}\$]{.math.inline}, where F = force, G = Gravitational Force (constant), m=mass of the objects, and r is the distance between the objects - Law of Gravitational: all objects in the universe attract each other through gravitational force, and depends on mass and distance (as the distance between two objects increases, the force of the gravity gets smaller - the closer, the greater the attraction) - Earth is attracted to the moon: the title bulges - Mass and Gravitational Force - Mass: the amount of matter in an object - The larger the object (mass), the leather gravity it has/ the smaller the object, the less gravity it has - Gravitational Acceleration Rate: 9.8 m/s\^2 - Relationship between Mass and Gravity - Mass = Same in every planet - Newton's Law of Motion: 1st Law - Law of Inertia - An object that is not moving or still, will remain still - An object that is moving or in motion, will remain in motion both in a straight line and at a constant speed, unless another force acts upon it - Include: Force, Friction (opposing force that affects the motion of things), Gravity - "Objects at rest stay at rest, objects in motion stay in motion." - Inertia is the natural state of objects (objects don't change their state unless acted on by force, which includes gravity and friction) - Newton's Law of Motion: 2nd Law - The amount of force applied to an object affects its speed - Acceleration of an object also depends on its mass - Include: Force, Acceleration, Mass (amount of mar=terial an object is made of) - Force = Mass x Acceleration - More force is needed to speed up the objects with more mass - Newton's Law of Motion: 3rd Law - Law of Action and Reaction - "For every action, there is an equal and opposite reaction." - Whenever an object pushes or presses against the second object, there is resistance from it returning the same amount of force = must apply enough force to make the second object move. - If objects 1 pushes against object 2, this creates resistance - Forces always come in pairs - Electromagnetism - One of the four fundamental forces of nature - Generates light and energy and holds atoms, matter, and the world together - Interaction between electric and magnetic fields - All matter has an electric charge (positive, negative, or zero): opposite charges attract, while like charges repel (electric forces bring and hold the atoms together) - Atoms gain a positive or negative charge (through the transfer of electrons) → form a measurable electric field → (if) those electrically charged particles start to move → the field becomes a flowing electric current → form a magnetic field around it - Electromagnetic field transmits waves of electromagnetic energy (radiation) into space - Radiation's intensity is determined by frequency (make up the electromagnetic spectrum) - A layer of liquid metals below the earth's surface churn and flow, generates electric currents that produce magnetic fields - Geodynamo: a process causes Earth's poles to attain positive and negative charges, creates a protective layer around the planet (protect us from solar radiation) - Electromagnetic Waves - Travel at the speed of light - Radio Waves - Microwaves - Infrared - Visible - Ultraviolet - X-Rays and Gamma Rays **Module 2: Electromagnetism in Medical Devices** - Electromagnetic waves consist of two: 1. Oscillating Magnetic Field 2. Oscillating Electric Field - Basic Properties of Waves - Wave's frequency: the number of full wavelengths that pass by a given point in space every second, SI unit is Hertz (Hz) = per seconds ([\$\\frac{1}{s}\\text{\\ or\\ }s\^{- 1}\$]{.math.inline}) - Wavelength and frequency are inversely proportional (the shorter the wavelength, the higher the frequency and vice versa), given the equation [*c* = *λν*]{.math.inline} (where [*λ*]{.math.inline} is the wavelength in meters, [*ν*]{.math.inline} is the frequency in hertz, [*c*]{.math.inline} is the speed of light which is equal to [3.00 × 10^8^ *m*/*s*]{.math.inline} - light always travels at the same speed), this relationship reflects the fact that; "all electromagnetic radiation, regardless of wavelength or frequency, travels at the speed of light."![](media/image4.png) - All EM waves (Electromagnetic Waves) have the same speed (the speed of light) - Frequency = wavelength (m) pass a point in a second - Speed of any EM wave: 300,000,000 m/s or 300,000 km/s - EM Spectrum - Quantization of Energy and the Dual Nature of Light - Is a chemical changes, a decrease in potential energy - The difference in PE is transformed into kinetic energy and light energy (law of conservation of energy) - Chemistry of Fire: 1. Where light is emitted is where the reaction occur 2. The flame (emitted light) is where oxygen and methane are rearranging into [CO~2~]{.math.inline} and [*H*~2~*O*]{.math.inline} 3. The heat we feel is the high kinetic energy [CO~2~]{.math.inline} and [*H*~2~*O*]{.math.inline} coming out of the flame 4. Heat transfers to the air and eventually dissipates because: - The high KE [CO~2~]{.math.inline} and [*H*~2~*O*]{.math.inline} collide with air particles → particles collisions transfer that initial KE to larger and larger amounts of air particles (the farther we get from the flame, the less we feel as the KE gets dispersed among all those air particles) - From Video - Simple Def: 1. absorption and emission 2. wavelength and temperature relationship 3. Planck's law - Electromagnetic Radiation - Matter absorbed/emitted energy only in whole-number multiples of the value hv (h is Planck's constant, [6.626 × 10^ − 34^ J.s]{.math.inline}, v is the frequency of the light absorbed/emitted) - The energy is not continuous but quantized (can only be transferred in individual 'packets' or particles of the size hv) - Each of these energy packets is known as a quantum (plural = quanta) - Energy cannot be transferred in anything less than a single quantum (it is the smallest units by which such energy can be transferred) - Photon - The elementary particle (quantum) of light - Can be absorbed/emitted by atoms and molecules - When absorbed, its energy is transferred to that atom or molecule - Energy is quantized → Photons' entire energy is transferred (we actually cannot transfer fractions of quanta, as it is the smallest possible energy packets) ![](media/image3.png) - Atoms or molecules lose energy → emit a photon that carries an energy exactly equal to the loss in energy of the atom or molecule → this change in energy is directly proportional to the frequency of photon emitted/absorbed → equation: [*E* = *hv*]{.math.inline} ([*E*]{.math.inline} is the energy of the photon absorbed/emitted, [*v*]{.math.inline} is the frequency of the photon, [*h*]{.math.inline} is the Planck's constant - [6.626 × 10^ − 34^ J.s]{.math.inline}) **Module 3: Life and Energy** - Thermodynamics - Shows us how to use energy efficiently, and minimize the wastes - Four laws of thermodynamics: 1. Zeroth Law - 'If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other.' 2. First Law - Law of Conservation of Energy - 'In a process without transfer of matter, the change in internal energy, [*ΔU*]{.math.inline} of a thermodynamic system is equal to the energy gained as heat, [*Q*]{.math.inline} less the thermodynamic work, [*W*]{.math.inline} done by the system of its surroundings.' - [*ΔU* = *Q* − *W*]{.math.inline} - [*ΔU*]{.math.inline} denotes the change in the internal energy of a closed system - [*Q*]{.math.inline} denotes the quantity of energy supplied to the system as heat - [*W*]{.math.inline} denotes the amount of thermodynamic work done by the system on its surroundings 3. Second Law - Entropy (The Measure of Disorder) - Heat does not flow from a colder body to a hotter body - However-- a refrigerator 1. uses energy and has a motor and a system of coils to move the heat out of the cold inside and release it outside 2. from the prof. = it works by circulating a refrigerant that absorbs heat from the food inside. The refrigerant in the evaporator coil changes from liquid to gas, cooling the interior. This process, called evaporation, requires heat, which is drawn from the food. To restart the cycle, the gaseous refrigerant is compressed by the compressor (located at the back of the fridge) into a high-pressure, hot gas. This gas is cooled in the condenser, turning it back into a liquid. The liquid refrigerant then passes through an expansion valve and returns to the evaporator, where it absorbs heat again, repeating the cooling process. 4. Third Law - 'As the temperature of a system approaches absolute zero, all processes cease, and the entropy of the system approaches a minimum value.' - Absolute Zero = all activity would stop if it were possible to achieve = -273 celsius or 0 K **Module 4: Chemistry and Everyday Interactions** - Related Chemical Structure 1. Sucrose - A disaccharide composed of: 2. Enzyme![](media/image6.png) - Are protein that acts as biological catalysts = helps break down or modify food components w/o being consumed in the process - Convert starch to simple sugars (in fermentation) 3. Anaerobic - Convert starch to simple sugars (in fermentation) - Major Chemical Reactions in Cooking 1. Fermentation - Carbohydrates molecules break down without using oxygen - Also known as anaerobic respiration - Does not require heat - 2 main types: 1. Alcoholic Fermentation (ethanol fermentation) 2. Lactic Acid Fermentation 2. Non-Enzymatic Browning - 2 kinds 1. The Maillard Reaction 2. Caramelization - Result in golden-brown color, richer flavor, alluring aromas - Food with a high sugar content itself can be caramelized (onions, apples, bananas) 3. Gluten Formation - 2 proteins (glutenin, gliadin) bind to each other to form a network that supports dough and allows bread to be light and fluffy (a present of amino acids in both proteins = help them form hydrogen bonds with each other while mixed with water) - These proteins are found in wheat and similar grains - Plays important role in making pasta, noodles, and pizzas - Baking bread: gluten can trap gas bubbles within the dough, helping to raise the dough and bring about that bread texture (chewy, airy) - Knead a dough: protein can bind and form thin, springy chains that help the dough hold its shape (when water is dispersed throughout the flour content) 4. Acid-Base Reactions - Acids taste sour (lemons, grapefruit, tomatoes) - Help soften foods rich in proteins (tough/sinewy cuts of meat) - 2 main bases that are cooking staples: eggs and baking powder/baking soda 5. Protein Denaturation - The weaker chemical bonds of protein molecules break down → transforming the once complex molecular structure of protein into a single long strand of amino acids - Occur when protein-rich egg whites are heated/mixed with an acidic substance - Can cause the protein to foam, add thickness = it binds ingredients in a batter/lead to better browning as amino acids binding with carbohydrates (Maillard Reaction) 6. Emulsification - The molecule containing one part that is drawn to water and another that is drawn to oil → the emulsifier capture the oil droplets and disperse them throughout the water → holding them in place and stabilizing the mixture - Egg yolks, butter = powerful emulsifying - Honey, mustard = flavorful emulsifiers - Material Science in Medical Implants - Dental Implants - Dental Post - Arch Wire / Brackets - Dental Bridges - Total Hip Replacement, Done Cement - Bone PLates - Screws - Intramedullary Nails - External Fixators - Why do we use metal in medical devices? (why use metal instead of corrosive one, is it not as stable as titanium ) - Corrosion Resistance - Biocompatibility - Strength and Stability **Module 5: Organic Chemistry and Biochemistry** **Module 6: Molecular Biology and Human Health (VDO)** - Nucleic Acids - 1 of 4 major types of macromolecules that are essential for all forms of life - Consist of 2 major macromolecules: +-----------------------------------+-----------------------------------+ | - Deoxyribonucleic Acid (DNA) | - Ribonucleic Acid (RNA) | +-----------------------------------+-----------------------------------+ | Carry the genetic instructions | | | for the development, functioning, | | | growth, and reproduction of all | | | organisms | | +-----------------------------------+-----------------------------------+ | Consist of polymers of a | | | sugar-phosphate-sugar backbone | | | with organic heterocyclic bases | | | attached to the sugars | | +-----------------------------------+-----------------------------------+ | Sugar is called Deoxyribose | Sugar is called Ribose | +-----------------------------------+-----------------------------------+ | Contains 4 bases | | | | | | 1. Cytosine | | | | | | 2. Thymine (Pyrimidine Bases) | | | | | | 3. Guanine | | | | | | 4. Adenine (Purine Bases) | | +-----------------------------------+-----------------------------------+ | In vivo consists of 2 | Single-stranded (mat adopt many | | antiparallel strands intertwined | secondary and tertiary | | to form the iconic DNA | conformations not unlike that of | | double-stranded helix | a protein) | +-----------------------------------+-----------------------------------+ - CRISPR Technology - Clustered Regularly Interspaced Short Palindromic Repeats - A technology that research scientist use to selectively modify the DNA of living organisms - Was adapted for use in the laboratory from naturally occurring genome editing systems found in bacteria![](media/image8.png) - Palindrome Sequence of a Double-Stranded DNA - Complementary strand must be read the same in the opposite direction (for a nucleotide sequence to be considered as a palindrome) **Module 7: Medical Technology and Healthcare (VDO)** - Robotic Surgery - Allows doctors to perform complex procedures with more precision, flexibility, and control - Often performed through tiny incisions (sometimes open surgeries) - Also called robot-assisted surgery - Often done through tiny openings in the skin and other tissues, this method called minimally invasive surgery - Robotic Surgery System - Includes: camera arm, mechanical arms (with surgical instruments attached to) - Surgeon controls the arms at the control center called console (near operating table) - Surgeon sees a magnified, high-definition, 3D view - How AI is pushing medical robotics toward autonomy - Telemedicine - The use of electronic information and communications technologies to provide/support healthcare remotely - Wearable Technology - Any technology that is designed to be used while worn - Smartwatches, smart glasses, smart rings, and implants - Often close to or on the surface of the skin, where they detect, analyze, and transmit information (such as vital signs) or ambient data - Is vetted for its reliability and security properties - Pacemaker - A small wearable device that is implanted under the skin in the chest to help the heartbeat the way it should - Send electrical signals to the heart to make sure that heart rate is never too slow - Heart condition = need a pacemaker for life - Healing from surgery = need a pacemaker for a while - Working of Pacemakers - Do not take over the work of the heart - Helps regulate the timing and sequence of the heartbeat (more like a safety in the event help regulating the heart) - Monitors the heart's electrical activity - The heart rate is too low = pacemakers will kick in and send a tiny electrical signal to the heart muscle that tells it to squeeze (contract) - Pacemakers make decisions on a beat-to-beat basis