Catching Up Chaps. 1-3 Physical Science Physical Science the study of matter and energy All matter has energy, even if it isnt moving E=mc 2 Chemistry all forms of matter and how they interact Physics the study of energy and how it affects matter Measurement Continued DENSITY Archimedes Principle The volume of liquid that is displaced is equivalent to the submerged volume. So how do you determine the average density of the human body? What might that tell you? Matter anything that has both volume and mass How do you measure the volume of a solid? L x W X H or displacement How do you measure the volume of a liquid? Graduated cylinder How do you measure the volume of a gas? Gas are compressible Trick question: Gases always take the volume of whatever container they are in. Mass, Weight and Gravity Mass the amount of matter something has. Does not change with location Weight a measure of the gravitational force exerted on an object Gravity a force of attraction between 2 objects based upon their masses and the distance between them Force of Gravity What happens to gravity as the distance between 2 objects doubles? triples? What is escape velocity? Free fall (on Earth) = 9.8 m/s/s Measuring Mass & Weight Mass is A measure of the amount of matter in an object Always constant despite location Measured with a balance Expressed in kg, g, mg, Weight is A measure of the gravitational force on an object Varies depending on location/proximity to large bodies Measured with a spring scale Expressed in Newtons (N) * They are the same on Earth What is a Newton? The newton is the SI unit for force; it is equal to the amount of net force required to accelerate a mass of 1 kg at a rate of 1 m/s 2 On Earth's surface, a mass of 1 kg exerts a force of approximately 9.8 N [down] (or 1.0 kilogram-force; 1 kgf= N by definition). The approximation of 1 kg corresponding to 10 N (1 decanewton or daN) is sometimes used as a rule of thumb in everyday life and in engineering.kilogram-forcedecanewton It is common to see forces expressed in kilonewtons or kN, where 1 kN = 1,000 N. Kilonewtons are often used for stating safety holding values of fasteners, anchors and more in the building industry.[2] They are also often used in the specifications for rock climbing equipment.[2] Mass is a Measure of Inertia Inertia the tendency of all objects to resist any change in motion An object at rest will remain at rest unless acted upon An object in motion will remain in unaltered motion unless acted upon *Mass is a measure of inertia because an object with a large mass is harder to move than one with smaller mass Describing Matter Physical Properties a property that can be observed and measured without changing the identity of the substance (color, odor, texture,melting point, boiling point state, thermal conductivity, malleability, ductility, solubility, density) Physical change a change that affects one or more physical properties but does not change the chemical properties Chemical properties Chemical Properties describe a substance based on its ability to change into a new substance with different properties (flammability, reactivity with other substances) Chemical Change when one or more substances are changed into entirely new substances Solid has definite shape and volume Liquid shape of its container with definite volume Gas changes in both shape and volume Plasma no shape no volume and particles have broken apart 2 Types of Solids Crystalline orderly 3-D arrangement of atoms or molecules Amorphous no order Solids Shape does not change Size does not change Particles do not have enough energy to break free from each other Particles vibrate in place Liquid Shape Changers Liquids change shape but not volume Hydraulics Surface tension viscosity Liquids Shape can change (takes the shape of container) Size does not change Particles have enough energy to slide past each other but not enough to break free completely Used in Hydraulic systems because size does not change. Gasses Change both Shape and Volume Pressure Boyles Law Charles Law Gases Size changes to fill up the container Shape changes to the shape of the container. Particles have enough energy to bounce off each other freely. Dont usually conduct electricity or react to magnetic field Charles Law When the temperature of a gas increases, the volume of the gas also increases. When the temperature of the gas decreases, the volume also decreases. When the volume of a gas decreases, the pressure of the gas increases. When the volume of a gas increases, the pressure of the gas decreases Boyles Law Divers Divers who breathe compressed air underwater face an extreme danger should they hold their breath while surfacing. The reduced external pressure causes the air in their lungs to expand. If the air held in their lungs is not exhaled, the expansion of air inside the lungs will cause the soft lung tissues to rupture. The results can be lethal and gruesome, causing one to literally drown in one's own blood. Absolutely the most important rule of diving is to always exhale when ascending (surfacing). It is equally important to surface slowly. Astronauts On Earth, the external pressure acting on the space suit is exactly one atmosphere. Ideally the air pressure within the spacesuit should also be one atmosphere (quite comfortable). The problem is that in space the external pressure is zero, and the spacesuit attempts to expand like an enormous balloon placing huge stress on the seams and joints of the suit. This is not only dangerous, but it also expands and stiffens the fabric and makes movement of arms and legs extremely difficult. To make the spacesuits both safe and comfortable, a pressure compromise is used. The nitrogen is removed from the air supply within the suit so that only the oxygen remains. This reduces the internal pressure of the suit by about 75%. This causes the spacesuit to undergo slight pressure expansion, but much less so than if it were filled with air at standard atmospheric pressure. Plasmas Aurora borealis Plasmas Size changes to fill container Shape changes to fill container Made up of very excited electrons of an element (never molecules) Only exist at very high energy levels Ex: stars, northern lights, fluorescent lights, fire, neon lights React to magnetic field, conduct electricity Most common state in the universe (stars) States of Matter Hint: its all about the energy Changes of State What happens to energy during a change of state? Endothermic Reaction Exothermic Reaction - Melting Solid to liquid Absorbing energy Freezing Liquid to Solid Removing Energy Vaporization What is Boiling? Evaporation Energy Pressure affects on Boiling Point Condensation Energy Sublimination Solid directly to Gas Temperature Change vs. Change of State Change of State The conversion of a substance from one physical form into another Temperature during a change of state. 1.What happens to the temperature as the ice melted? 2. What happens to the thermal energy as the ice melted? Changes of State (hint: its all about the energy) Endothermic absorbs energy Melt particles of a solid gain enough energy to break free and slide past other particles. Vaporize particles of a liquid gain enough energy to break free of liquid. Sublimate particles of a solid gain enough energy to become a gas Exothermic releases energy Condense particles of a gas lose energy and become a liquid. Freeze particles of a liquid lose energy, are unable to break free of each other. Deposition particles of a gas lose so much energy they become a solid (e.g. frost, snow) Hail snowflakeRain How to keep fruit from freezing: Temperature falls below 0 o C Mist trees with cool water Water loses energy and freezes, orange doesnt. Ice melts, oranges are saved. Elements, Compounds and Mixtures Ms Shader Atom The smallest unit of an element, having all the characteristics of that element Element Pure substance all particles are alike. Substance that is made of only one type of atom. Cannot be broken down using chemical or physical methods Cannot be manufactured using chemical or physical methods Ex: iron, gold, oxygen Molecule The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms. H2OH2O C 6 H 12 O 6 Compounds Pure substance all particles are alike Made of molecules two or more atoms chemically joined together. Cannot be broken down using physical methods. Can be broken down using chemical methods (heating, acid, chemical reactions) Ingredients are in definite ratios Ex: CO, CO 2, H 2 O, H 2 O 2, C 6 H 12 O 6, NaCl, HCl, NOT a pure substance (made of more than one type of particle) Particles: are not chemically bound together retain their chemical and physical properties. Can be separated using physical means Components are NOT in definite ratios Ex: kool-aid, spice mix, pizza, air, granite, salt water, blood, Mixtures Types of Mixtures Homogenous appears to be a single substance (cannot see particles) Solution black coffee, pepsi, air Colloid fog, shaving cream Heterogenous can identify different ingredients Suspension salad dressing smoke Solution A mixture that appears to be a single substance. Particles are so tiny they do not scatter light Made of a solute and a solvent. Solute the dissolved substance Solvent a substance that dissolves another material to form a solution. Examples of Solutions SolutionSolventSolute Coca colaWaterFlavors CoffeeWaterCoffee Kool aidWaterSugar OceanWaterSalts AirNitrogenOxygen AntifreezeWaterAlcohol Sterling silverSilverCopper SeltzerWaterCO 2 Solubility The amount of a solute that will dissolve in a solvent at a particular temperature. Saturated solution a solution that contains all the solute it can hold at a particular temperature. Rate of Dissolving Three factors affect how quickly a solute dissolves: Mixing (shaking, agitating) Heating Crushing Mixing and crushing do not affect how much will dissolve, just how fast it will dissolve!!!! Separating Mixtures Ingredients keep their chemical/physical characteristics, so can be separated using physical methods. Example: Koolaid in H 2 O distillation (boil off the water, flavorings remain behind) Magnets separate magnetic metals from other ingredients. Filters separate ingredients by size Element a substance made from only one type of atom. Elements cannot be reduced to simpler substances by normal chemical means Elements, Compounds and Mixtures Ms Shader Atom The smallest unit of an element, having all the characteristics of that element Element Pure substance all particles are alike. Substance that is made of only one type of atom. Cannot be broken down using chemical or physical methods Cannot be manufactured using chemical or physical methods Ex: iron, gold, oxygen Molecule The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms. H2OH2O C 6 H 12 O 6 Compounds Pure substance all particles are alike Made of molecules two or more atoms chemically joined together. Cannot be broken down using physical methods. Can be broken down using chemical methods (heating, acid, chemical reactions) Ingredients are in definite ratios Ex: CO, CO 2, H 2 O, H 2 O 2, C 6 H 12 O 6, NaCl, HCl, NOT a pure substance (made of more than one type of particle) Particles: are not chemically bound together retain their chemical and physical properties. Can be separated using physical means Components are NOT in definite ratios Ex: kool-aid, spice mix, pizza, air, granite, salt water, blood, Mixtures Types of Mixtures Homogenous appears to be a single substance (cannot see particles) Solution black coffee, pepsi, air Colloid fog, shaving cream Heterogenous can identify different ingredients Suspension salad dressing smoke Solution A mixture that appears to be a single substance. Particles are so tiny they do not scatter light Made of a solute and a solvent. Solute the dissolved substance Solvent a substance that dissolves another material to form a solution. Examples of Solutions SolutionSolventSolute Coca colaWaterFlavors CoffeeWaterCoffee Kool aidWaterSugar OceanWaterSalts AirNitrogenOxygen AntifreezeWaterAlcohol Sterling silverSilverCopper SeltzerWaterCO 2 Solubility The amount of a solute that will dissolve in a solvent at a particular temperature. Saturated solution a solution that contains all the solute it can hold at a particular temperature. Rate of Dissolving Three factors affect how quickly a solute dissolves: Mixing (shaking, agitating) Heating Crushing Mixing and crushing do not affect how much will dissolve, just how fast it will dissolve!!!! Separating Mixtures Ingredients keep their chemical/physical characteristics, so can be separated using physical methods. Example: Koolaid in H 2 O distillation (boil off the water, flavorings remain behind) Magnets separate magnetic metals from other ingredients. Filters separate ingredients by size Element a substance made from only one type of atom. Elements cannot be reduced to simpler substances by normal chemical means