Science Flashcards
Physical property of solids, liquid, gases is much as color, MAs density, hardness and electrical and thermal conductivity.
Solids:
Matter: that undergoes physical change
Physical changes
What physical changes do matter undergo.
-evaporation and freezing
Matter that undergoes chemical changes
Atoms in reactants rearrange to form products with new physical and chemical properties.
Parts of atom
Protons, neutrons, and electrons.
Matter that consist of atoms and molecules in various arrangements.
Constituents of molecules and compounds naming common elements
Hydrogen, oxygen, and iron
How are elements organized on periodic table. On basis of their a topic and chemical properties.
Solutions such as acidic, basic, and neutral solutions you also need to know examples of solutions with different ph levels, such as soft drinks i liquid detergents and water.
Mixtures that are separated based on physical of chemical properties.
Motion based on position, displacement, speed velocity and acceleration
Displacement? Position?, speed, velocity acceleration.
Forces. (Pushes + pulls) such as:
Gravity does what
Magnetism does what
Friction act on objects and ma change their motion if these forces are not in balance.
Electrical charges or magnetic poles
Opposit attract = Proc duces attractive forces
Same - produces repulsive forces.
Simple machines
Forms of energy
Wind, solar, chemical, electrical, magnetic, nuclear, s sound, light, and
Electromagnetic
What is electromagnetism
Law of matter
Law of energy
Energy in a system is conserved, but may be changed from one form to another, as in an electrical motor or generator, and s peed and energy are related.
What is heat?
Thermal energy
What is temperature?
What is temperature measurement system.
Heat transfers by ?
Conduction, convection, and radiation
What is conduction
‘Heat transfer by stove
What is convection
Heat transfer by oven.
How does heat transfer in earths mantle
How does heat transfer through radiation.
Include the sun example.
Sources of light
Sun, light bulbs, excited atoms
What are excited atoms
Neon in neon lights i and flouresant lights
Interactions of light with matter
Vision /photosynthesis, etc L learn more
Optical properties of waves
Wave lengths, amplitude, and frequency l there is more)
-Light
-sound
-Reflection
Refraction (bending light through a prism)
And their applications and technologies
Conservation of energy resources in terms of renewable and non renewable natural resources and their use in society
Sublimation
Makes it possible for some elements and compounds to transition from a solid to a gas phase without becoming a liquid .A common example is a block of dry ice (CO 2) which will turn into a gas at room temperature. Some gases can transition directly to a solid such as the formation of frost. This is called deposition.
Solid
Ability to retain their shape/ incompressible/ melts when heated and vaporize only slightly/ all substances become solid if cooled sufficiently
Ext rocks, crystals, wood, feather, ice
Liquids
Liquids take on the shape of their containers ,yet cannot be compressed to any significant extent the volume of a liquid is constant unless evaporation is occurring liquids crystallize windshield sufficiently while heat causes liquids to vaporize the liquid state is intermediate between the solid and gaseous states with regard to molecules motion and attractive forces between molecules.
Examples are water, oil ,milk ,and honey
Gases
Gases expand to fill any available space gases is a compressible fluid while its volume determined by the pressure and temperature of the environment the volume varies inversely with the pressure a relationship known as Boyles law if the pressure increases the volume decreases the reverse is true as well
Examples are helium air and Steam
Mass
Mass is the amount of matter in a chemical substance, in every day usage mass is commonly confused with weights. but in physics and engineering weight means the strength of the gravitational pool on the object, that is , how heavy it is measured in newtons (the force needed to accelerate on KG of mass ). in every day situations the weight of an object is proportional to its mass which usually makes it acceptable to use the same word for both concepts
Density
For a Homo Jenuis object is determined by dividing the mass by the volume the mass is normally measured with a appropriate scale or balance the volume may be measured directly from the geometry of the objects or by the displacement of a fluid for example if steel and would have equal dimensions the steel would have a greater mass as it is more dense
D= M/ V
Or
Density = mass/ volume
Hardness
Refers to various properties of matter in the solid phase that give it a higher resistance to its shape changing when force is applied hard matter is contrasted with soft matter however the behavior of solid materials under force is complex resulting in several different scientific definitions of what might be called hardness in every day usage.
Three principal operational definitions of hardness:,
Scratch hardness
Indentation hardness
Rebound hardness.
Scratch hardness
Resistance to fracture or plastic (permanent) deformation due to friction from a sharp objects
Indentation hardness
Resistance to plastic (permanent) deformation due to a consistent load from a sharp object
Rebound hardness.
Height of the balance of an object dropped on the material related to elasticity
Months ‘ scale of hardness
Rates minerals and put them on a scale from one to 10 what is the softest antennas the hardest determined by the ability of a harder mineral to scratch a softer mineral
for example talc is at one and a diamond is at 10
Physical properties
Are the characteristics that make up the physical composition of a substance physical properties include color form electrical conductivity and density
What is electrical conductivity
Physical changes
Do not involve one substance changing into another water for example can change from a gas water vapor to liquid water to a solid ice but the water molecules do not change the particular state of water is determined by pressure and temperature.
Chemical changes
Occur when a substance is changed into something else a chemical change occurs whenever compounds are formed or decomposed during this reaction there is a rearrangement of atoms that makes or breaks chemical bonds this change is usually not reversible unlike physical changes which typically are reversible an example of a chemical change is the formation of rust iron chemically reacts with air and water to form rust (ferrous oxide) And is unable to change back to iron ensure a chemical change is a change of one substance into a different substance.
Chemical reactions
Show the number of molecules or formula units of the reactants and products for example nitrous oxide is a colorless odorless gas that causes mild hysteria when inhaled hence the name laughing gas it is prepared by Heating ammonium nitrate crystals.
Atoms
Are made up of a several tiny parts at the center of an atom is a core called the nucleus the nucleus is made up of particles called protons and neutrons protons have a positive electrical charge and neutrons have a no charge electrons move around the nucleus an electron clouds electrons have a negative charge and they are attracted to the positively charged protons in the nuclear us this attraction keeps the electrons in orbit around the nucleus
Pg 298
Chemical elements
Chemical elements are composed of only one atom and cannot be separated into different substances except in some instances by radioactive decay or by nuclear reaction elements are assigned atomic numbers equal to the number of protons in the nucleus of the atom element has a different number of protons the sum of the protons and neutrons gives an average atomic mass for the element
P.299
Compounds
Are formed by the chemical combination of two or more elements in a fixed ratio water for example is made up of molecules with the composition H2O and the structure shown in the figure that follows the straight lines denote bonds one water molecule is built from two atoms of hydrogen and one atom of oxygen ordinarily table salt is a compound composed of one atom of sodium in one atom of chlorine (NaCI, sodium chloride).
The periodic table of
The periodic table of elements arranges all of the known elements from left to right and top to bottom in order of increasing atomic number and they generally coincide with their increasing atomic mass roles are reign so that elements with similar properties fall into the same vertical columns to form groups or families For example fluorine and chlorine are highly reactive gases that form strong acids and solutions helium neon and argon are in earths noble gases that do not form chemical compounds as of 2006 the table contains 117 chemicals elements whose discoveries have been confirmed 94 are found naturally on the earth and the rest are synthetic elements that have been produced artificially in particle accelerators
 PH
PH is measured of the acidity or Basicity of a solution the pH scale is not an absolute scale it is related to a set of standard solutions who is PH is established by international agreement
Pure water is said to be neutral the pH for pure water at 25°C is close to 7.0 when foreign substances are dissolved in water it creates a solution solution with a pH of less than 7.0 are said to be acidic and solutions with a pH greater than 7.0 are said to be basic or alkaline pH measurements are important for medicine biology chemistry food science environmental science oceanography and many other applications
PH scale on page 300
Mixture
A mixture is a substance made by combining two or more different materials without a chemical reaction occurring the objects do not bond together they are the product of a mechanical blending or mixing of chemical substances each ingredient substance retains its own chemical properties and make up for example a mixture of salt and pepper would still be identifiable as salt and pepper while there are no physical changes in a mixture the chemical properties of a mixture such as its melting point may differ from those of its components mixtures can usually be separated into their original components by mechanical means and are either homogeneous or hetero genius
Scientific method-in part
The scientific method requires observation conjuncture calculation prediction in testing success of scientific Revelations I have told us that today’s laws are not certain only more accurate than yesterday’s loss
Measurements
Measurement is the beginning of scientific wisdom The psychiatrist first reaction to a new idea is to ask can it be measured can I describe it with numbers numerical data can be manipulated with many powerful mathematical tools from arithmetic and geometry to statistics in differential equations physical quantities range from subatomic smallest to astronomic hugeness and so the numbers are conveniently expressed in scientific notation in which any number is written in the form
See page 301 chapter 4 subtest science
Three basic units of metric system
A unit 1000 times the basic unit has the prefix kilo and so a kilometer equals 1000 m the prefix Milli as in millimeter denotes a unit 1/1000 Of the basic unit a little
See page 301 principles of motion energy
Basic units of the metric system or length volume mass
Motion
Motion means that there is a constant change in the location of a body and is described by stating an objects position velocity and acceleration
Velocity
Velocity is the rate of change of position with time for example and Automobile that is 100 miles farther along a highway at 3 PM then at 1 PM has an average velocity during the interval of:
Newtons first law of motion p 302
The first law is referred to as the law of inertia in the absence of the application of an outside force such as gravity or friction a body at rest will remain at rest while a body moving in a straight line will continue to move in a straight line with uniform speed simplified without outside force is a stationary object will never move and without outside forces an object in motion will never stop or deviate from his course
Newton second law of motion
The second law relies on the first law and proposes that the acceleration of an object is proportional to the force supply simplify the more force the more acceleration
Newtons third law of motion
The third law asserts that for every action applied force there is an equal and opposite reaction
Gravitation
Is a natural phenomenon by which objects with mass attract one another gravitation compels dispersed matter to call Luis and this is accounts for the very existence of the earth the sun and most of the microscopic objects in the universe. it is responsible for keeping the earth and the other planets in their orbit around the sun for keeping the moon and its orbit around the earth for the formation of tides for convection by which hot fluids rise for heating the interiors of forming stars and planets to very high temperatures and for various other phenomenon that we observe.
The terms gravitation and gravity are mostly interchangeable in every day use gravity refers specifically to the gravitational force exerted by the earth on objects and it’s vicinity
Magnetism
Magnetism is displayed by permanent magnets and around electric currents all of us have had the opportunity to study the interesting properties of permanent magnets small iron bars or Ironhorse shoes or the aligned internal structures Indus by other magnets the north pole of one magnet attracts the south pole of another but like poles repel each other either pole can attract unmagnetized iron objects iron feeling spread on a piece of paper above a bar magnet become arranged in a pattern that maps a magnetic field in the space around the magnet See the following figure on page 302 and 303 the earths magnetic field orient the iron needles of navigational compasses an electric current also generates a magnetic field, demonstrating an intimate connection between electricity and magnetism. Recent work has united these phenomena, as well as light, into electromagnetic radiation.
Simple machine
Is a mechanical device that changes the direction or magnitude of a force.in general simple machines can be defined as the simplest mechanism that use mechanical advantage also called leverage to multiply force. A mechanical advantage results in less force applied over a greater distance it helps to make work easier a simple machine uses a single applied force to do work against a single load force. ignoring friction losses, The work done on the load is equal to the work done by the applied force. Simple machines can be used to increase the amount of the output force, at the cost of a proportional decrease in the distance moved by the load. The ratio of the output to the input force is called the mechanical advantage.
Lever, pulley also called block, inclined plane, screw, see page 304
Energy
Forms of energy include solar, chemical, electrical, magnetic, nuclear, sound, light, and electromagnetic. Energy is the ability to perform work, to move objects. That ability can take several forms:
Kinetic energy
Potential energy
Consider a baseball thrown vertically upward. Its speed decreases upward because the acceleration of gravity is acting downward. The rising ball loses kinetic energy ( slows down) As it gains potential energy( rise high). at the peak of the balls flights the ball is instantaneously at rest with no kinetic energy but maximum stored potential energy. As the ball falls the potential energy is transformed into kinetic energy and the ball accelerates. Thermal energy also exist, for it has been shown that heat can be converted to motion, and motion can produce heat. electricity and magnetism are steal other forms of energy, or they can be converted into heat and motion. Noticed that this key concept of energy is the abstract idea that there is something identical in motion, heat, and electricity, which appears so different to our senses. It is impossible to define the various forms of energy so that their mathematical sum is constant. The law of conservation of energy states that energy can be Neither created nor destroyed.
Kinetic energy
The energy possessed by a moving object is called kinetic energy
Potential energy
An object in a unstable position has potential energy,for the position could be converted into movement.
Electricity
Is a form of energy that can be used to produce sound, light, heat, and power. Electricity exist where the number of negative electrons does not precisely equal the number of positive protons. Electrons are held in the atom by an electrical force and have an electrical charge. When the electrons are not held tightly in their atom, the electrons can move freely and can carry electricity from one place to another. When the electrons flow in one direction, the flowing electricity is referred to as currents. An electric current is simply a flow of electrons through a wire. Electricity can flow easily through materials that conduct electricity. Materials that have high conductivity include metals such as aluminum ( Al), iron )FE) , nickel (Ni), silver(Ag) and gold (Au). And materials that act as insulators (poor conductors of electricity), The electrons are held tightly inside their Adams and the electrons cannot move freely. Some examples of good insulators include plastic rubber, glass, air, and would.
Electric circuit
Is simply the path or circuit and electric current flows electricity requires a complete pass for the electrons to flow. If the path is broken and there are no alternative paths for the electrons to follow, the electrons will not move. Electric circuits make it possible for electric energy to operate a vast range of technology.
Static electricity
Results when electrical charges build up or increase on the surface of a material. In static electricity, there is no current flowing as would be found in electrical outlets. When certain materials are rubbed together, electrons can move from one object to the other. A material can become negatively or positively charged if electrons in the material are gained or lost – an example would be the spark a person might get by walking across a wall rug and then touching a metal door knob. Static electricity can also result by rubbing a balloon against your hair or against a wool sweater. Rubbing the objects together can result in the balloon becoming negatively charged and your hair becoming positively charged. Since opposite charges attract, the balloon will clean to your hair. Lightning is another example of Static electricity.
Light
Light seems to travel and perfectly straight lines as rays the direction of a ray changes at the interface between two transparent materials, like air and water. Some of the light is reflected, the angle of reflection being equal to the angle of incidence. The portion of the light that crosses the boundary is, however, deflected in another direction, and the angle of refraction does not equal the angle of incidence.
Reflection
Refraction
