Science A CSA Past Paper PDF

CSA 100: Competency and Skills Appraisal on General Education Science Reviewer 2 Phases of the Moon - Solar Eclipse happens during the new moon phase - Lunar Eclipse happens during the full moon phase The umbra (Latin for "shadow") is the inner...

CSA 100: Competency and Skills Appraisal on General Education Science Reviewer 2 Phases of the Moon - Solar Eclipse happens during the new moon phase - Lunar Eclipse happens during the full moon phase The umbra (Latin for "shadow") is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. An observer within the umbra experiences a total occultation. The penumbra (from the Latin paene "almost, nearly" and umbra "shadow") is the region in which only a portion of the light source is obscured by the occluding body. An observer in the penumbra experiences a partial eclipse. The antumbra (from the Latin ante "before" and umbra "shadow") is the region from which the occluding body appears entirely within the disc of the light source. An observer in this region experiences an annular eclipse, in which a bright ring is visible around the eclipsing body. Layers of the Atmosphere - Troposphere - the lowest layer of our atmosphere. Starting at ground level, it extends upward to about 10 km (6.2 miles or about 33,000 feet) above sea level. Air pressure drops, and temperatures get colder, as you climb higher in the troposphere. - Stratosphere (ozonosphre) - The stratosphere extends from the top of the troposphere to about 50 km (31 miles) above the ground. The infamous ozone layer is found within the stratosphere. Commercial passenger jets fly in the lower stratosphere, partly because this less-turbulent layer provides a smoother ride. - Mesosphere - It extends upward to a height of about 85 km (53 miles) above our planet. Most meteors burn up in the mesosphere. Unlike the stratosphere, temperatures once again grow colder as you rise up through the mesosphere. - Thermosphere (ionosphere) - High-energy X-rays and UV radiation from the Sun are absorbed in the thermosphere, raising its temperature to hundreds or at times thousands of degrees. However, the air in this layer is so thin that it would feel freezing cold. The approximate boundary between our atmosphere and outer space, known as the Kármán Line, is in the thermosphere, at an altitude of about 100 km. Many satellites actually orbit Earth within the thermosphere. Variations in the amount of energy coming from the Sun exert a powerful influence on both the height of the top of this layer and the temperature within it. Because of this, the top of the thermosphere can be found anywhere between 500 and 1,000 km (311 to 621 miles) above the ground. Aurora borealis and aurora australis is formed and observed in this layer  - Exosphere - Although some experts consider the thermosphere to be the uppermost layer of our atmosphere, others consider the exosphere to be the actual "final frontier" of Earth's gaseous envelope. Different definitions place the top of the exosphere somewhere between 100,000 km (62,000 miles) and 190,000 km (120,000 miles) above the surface of Earth. Water Cycle Processes - Evaporation - the change of state in a substance from a liquid to a gas - Condensation - the change of state in a substance from a gas to liquid also the process of forming clouds - Precipitation - when tiny condensation particles, through collision and coalescence, grow too large for the rising air to support, and thus fall to the Earth. Precipitation can be in the form of rain, hail, snow, or sleet. - Transpiration - the evaporation of water from plants through stomata. Stomata are small openings found on the underside of leaves that are connected to vascular plant tissues. - Runoff - occurs when there is excessive precipitation and the ground is saturated (cannot absorb any more water). Rivers and lakes are results of runoff. Hurricane is also known as typhoon Twister or tornado is the smallest revolving weather phenomenon Denitrification is the process of converting nitrate to nitrogen gas and nitrous oxide Desalination is the process of developing fresh water from salt water A diverging lens can form an upright, reduced, and virtual image Blue light wave travel and scatter more than red light because this has higher wavelengths. The scattering of light is best explained by Rayleigh scattering or the dispersion of electromagnetic radiation by particles that have a radius less than approximately 1/10 the wavelength of the radiation. Light interference is the phenomena of multiple light waves interacting with one another under certain circumstances, causing the combined amplitudes of the waves to either increase or decrease. This is responsible for alternating light and dark bonds when light passes through two or more narrow slits. Reflection is the bouncing of light when it hits a surface. Refraction is the bending of light as it passes through a different region/medium. In a system when a part changes from higher energy to lower energy state the energy is released/emitted. If it changes from lower to higher state the energy is stored. In quantum theory, energy of light is carried in units called photons The particle nature of light is best explained by the photoelectric effect. The photoelectric effect is the emission of electrons from a material caused by electromagnetic radiation such as ultraviolet light. Electrons emitted in this manner are called photoelectrons. Isochoric process is also known as a constant-volume process. It is a thermodynamic process where the total volume of the system remains constant. Isobaric process refers to constant pressure, when other factors like temperature or volume can change in a system. Isothermal process is one where work and energy are expended to maintain an equal temperature (called thermal equilibrium) at all times. Adiabatic refers to a process in which no heat is transferred into or out of a system, and the change in internal energy is only done by work. Heat Transfer - Conduction: when molecules of matter are in direct contact with each other - Convection: when heat is transferred through the movement of gas or liquid  - Radiation: when heat is transferred through space Magnetic field moves from its north pole to south pole Electric current moves from positive to negative in a circuit Electron flows from negative to positive in a circuit Iron can turn into temporary magnet through the process of Induction Coulomb’s Law - the electrical force between two charged objects is directly proportional to the product of the quantity of charge on the objects. Kirchoff’s Law - the sum of all potential rises and potential drops in any loop (closed circuit) is zero Law of Electrolysis - the mass of a substance deposited at any electrode is directly proportional to the amount of charge passed. Ohm’s Law - that the electric current through a conductor between two points is directly proportional to the voltage across the two points. Charge - is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Circuit - a closed, continuous path through which electrons can flow Resistor - an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Voltage - the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop. Law of Inertia – object at rest tends to be at rest, object in motion tends to be in motion unless an external force is acting on it Law of Acceleration - that the acceleration of an object is directly related to the net force and inversely related to its mass. Acceleration of an object depends on two things, force and mass. Law of Interaction – in every action there is an equal yet opposite reaction Simple Machines: - Inclined plane: simple machine consisting of a sloping surface, used for raising heavy bodies. - Pulley: a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. - Wheel and axle: the assembly formed by two disks, or cylinders, of different diameters mounted so they rotate together around the same axis. - Lever: a rigid bar resting on a pivot, used to help move a heavy or firmly fixed load with one end when pressure is applied to the other. Displacement: the shift in location when an object in motion changes from one position to another. Final velocity: is equal to its initial velocity plus acceleration multiplied by the time it travelled and can be given as: v = u + at. where, v = final velocity. Initial velocity: the velocity of an object at the beginning of a sequence or motion. Formula for work: - W (Joules) = P (power in Watt) x s (time in sec) - Power (kg J/s or kg m2 /s 3) = Joules (kg m2 / s 2 ) x Seconds (s) Net force: the sum of all the forces acting on an object. Kinetic energy is an energy in motion while potential energy is a stored energy in stationary position Scalar quantity only has magnitude but no direction example is temperature while vector quantity has both magnitude and direction like weight. DNA Nitrogenous Base Pairing: - Adenine (A) is to Thymine (T) - Guanine (G) is to Cytosine (C) The Biomolecules in the body are: - Carbohydrates – energy source of the body - Proteins – structural components of the body - Lipids – thermal insulator of the body  - Nucleic Acids – responsible for genetic information Organic compound are molecules with carbon or carbon chain in its structure like glucose molecules Emulsification is the process of combining liquids which don’t usually mix through substances that acts as agents like the egg yolk in making mayonnaise. Study the scale of pH below: Acids react with carbonates (a mineral with carbonate ion) which form carbon dioxide Temperature also refers to the kinetic energy in particles of matter In every chemical reaction, the number of atoms of reactants (left side of arrow) will always be equal to the amount of atoms in every element of the products (right side of arrow) Different types of Chemical Bonds: o Covalent Bond - a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These bonds are common in organic molecules o Ionic Bond - type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. These bonds form salt substances which when dissolved in water, could conduct electricity. o Metallic Bond - force that holds atoms together in a metallic substance. Such a solid consists of closely packed atoms. In most cases, the outermost electron shell of each of the metal atoms overlaps with many neighboring atoms.  Common Types of Chemical Reaction:  The atomic number is always equal to the number of protons and electrons The atomic mass is equal to the total number of protons and neutrons Properties of Metals: o State: Metals are solids at room temperature with the exception of mercury, which is liquid at room temperature (Gallium is liquid on hot days). o Luster: Metals have the quality of reflecting light from their surface and can be polished e.g., gold, silver and copper. o Malleability: Metals have the ability to withstand hammering and can be made into thin sheets known as foils. For example, a sugar cube sized chunk of gold can be pounded into a thin sheet that will cover a football field. o Ductility: Metals can be drawn into wires. For example, 100 g of silver can be drawn into a thin wire about 200 meters long. o Hardness: All metals are hard except sodium and potassium, which are soft and can be cut with a knife. Metal are strong materials and have high tensile strength. o Valency: Metals typically have 1 to 3 electrons in the outermost shell of their atoms. o Conduction: Metals are good conductors because they have free electrons. Silver and copper are the two best conductors of heat and electricity. Lead is the poorest conductor of heat. Bismuth, mercury and iron are also poor conductors o Density: Metals have high density and are very heavy. Iridium and osmium have the highest densities whereas lithium has the lowest density. o Melting and Boiling Points: Metals have high melting and boiling points. Tungsten has the highest melting and boiling points whereas mercury has the lowest. Sodium and potassium also have low melting points. A graduated cylinder with water can measure the volume of irregular shaped solids