FIRST TERM UNIT 0: SCIENTIFIC KNOWLEDGE U.0_3: Physical quantities. Física y química 3º E.S.O. FIRST TERM UNIT 0: SCIENTIFIC KNOWLEDGE U.0_3: Physical quantities. U.0_3_4: Physical quantities. Conversion factors. U.0_3_4 d1
Bloque 1. La actividad científica. El método científico: sus etapas. Medida de magnitudes. Sistema Internacional de Unidades. Notación científica. Utilización de las Tecnologías de la Información y la Comunicación. El trabajo en el laboratorio. Proyecto de investigación. Criterios de evaluación C.E.1.1. Reconocer e identificar las características del método científico. CMCT E.A.1.1.1. Formula hipótesis para explicar fenómenos cotidianos utilizando teorías y modelos científicos. E.A.1.1.2. Registra observaciones, datos y resultados de manera organizada y rigurosa, y los comunica de forma oral y escrita utilizando esquemas, gráficos, tablas y expresiones matemáticas. C.E.1.2. Valorar la investigación científica y su impacto en la industria y en el desarrollo de la sociedad. CCL, CSC E.A.1.2.1.Relaciona la investigación científica con las aplicaciones tecnológicas en la vida cotidiana. C.E.1.3. Conocer los procedimientos científicos para determinar magnitudes. CMCT E.A.1.3.1. Establece relaciones entre magnitudes y unidades utilizando, preferentemente, el Sistema Internacional de Unidades y la notación científica para expresar los resultados. C.E.1.4. Reconocer los materiales e instrumentos básicos presentes en los laboratorios de Física y Química; conocer y respetar las normas de seguridad y de eliminación de residuos para la protección del medio ambiente.CCL, CMCT. CAA, CSC. E.A.1.4.1. Reconoce e identifica los símbolos más frecuentes utilizados en el etiquetado de productos químicos e instalaciones, interpretando su significado. E.A.1.4.2. Identifica material e instrumentos básicos de laboratorio y conoce su forma de utilización para la realización de experiencias respetando las normas de seguridad e identificando actitudes y medidas de actuación preventivas. C.E.1.5. Interpretar la información sobre temas científicos de carácter divulgativo que aparece en publicaciones y medios de comunicación. CCL, CSC E.A.1.5.1. Selecciona, comprende e interpreta información relevante en un texto de divulgación científica y transmite las conclusiones obtenidas utilizando el lenguaje oral y escrito con propiedad. E.A.1.5.2. Identifica las principales características ligadas a la fiabilidad y objetividad del flujo de información existente en internet y otros medios digitales. C.E.1.6. Desarrollar y defender pequeños trabajos de investigación en los que se ponga en práctica la aplicación del método científico y la utilización de las TIC.CCL, CMCT, CD, SIEP E.A.1.6.1. Realiza pequeños trabajos de investigación sobre algún tema objeto de estudio aplicando el método científico, y utilizando las TIC para la búsqueda y selección de información y presentación de conclusiones. E.A.1.6.2. Participa, valora, gestiona y respeta el trabajo individual y en equipo. U.0_3_4 d2
Pau mide tanto como 2,15 veces la unidad de longitud que se toma como referencia. H Pau = 2,15 m Magnitud Número Unidad U.0_3_4 d3
CHANGING UNITS AND USING CONVERSION FACTORS All the quantities are related to only seven base quantities. U.0_3_4 d4
CHANGING UNITS AND USING CONVERSION FACTORS Magnitudes fundamentales SISTEMA INTERNACIONAL DE UNIDADES MAGNITUD UNIDAD SÍMBOLO MAGNITUDES FUNDAMENTALES LONGITUD Metro m MASA Kilogramo kg TIEMPO Segundo s INTENSIDAD DE CORRIENTE ELÉCTRICA Amperio A TEMPERATURA Kelvin K CANTIDAD DE SUSTANCIA Mol mol INTENSIDAD LUMINOSA Candela cd U.0_3_4 d5
CHANGING UNITS AND USING CONVERSION FACTORS Una magnitud derivada es aquella que se obtiene mediante expresiones matemáticas a partir de las magnitudes fundamentales (densidad, superficie, velocidad) Superficie de un cuadrado= Base x Altura= L x L La superficie es una magnitud derivada U.0_3_4 d6
MAGNITUDES FÍSICAS. UNIDADES Y MEDIDAS MÚLTIPLOS Y SUBMÚLTIPLOS Tabla de prefijos en el SI 1 ms = 10 -3 s 1 1 Prefijos “mili” = “la milésima parte de” s s 10 -3 s 1000 10 3 We compose the symbol for each unit by combining the prefix symbol and the basic unit symbol 1 mm = 10 -3 m The 20 SI prefixes used to form decimal multiples and submultiples of SI units: 1 1 Prefix “milli” = “one thousand times smaller than a ...” m m 10 -3 m 1000 10 3 U.0_3_4 d7
Metric Basic Units and Prefixes U.0_3_4 d8
1 ms = 10 -3 s Example: Tabla de prefijos en el SI +1.60 x 101 s CHANGING UNITS AND USING CONVERSION FACTORS We are going to use CONVERSION FACTORS to change units Tabla de prefijos en el SI 1 ms = 10 -3 s 1 1 Prefijos “mili” = “la milésima parte de” s s 10 -3 s 1000 10 3 Example: The 20 SI prefixes used to form decimal multiples and submultiples of SI units: 1 ms = 10 -3 s 10 -3 s +1.60 x 101 s t = +1.60 x 104 ms 1 ms U.0_3_4 d9
Calculate the charge of a single proton in picocoulombs CHANGING UNITS AND USING CONVERSION FACTORS MÚLTIPLOS Y SUBMÚLTIPLOS Tabla de prefijos en el SI Calculate the charge of a single proton in picocoulombs The 20 SI prefixes used to form decimal multiples and submultiples of SI units: 1 pC = 10 -12 C 1 pC +1.60 x 10-7 pC Q = +1.60 x 10-19 C 10 -12 C U.0_3_4 d10
CHANGING UNITS AND USING CONVERSION FACTORS Unit Factor Method The Unit Factor Method is a standard method to perform unit conversions in Science. U.0_3_4 d11
Conversion Factor Method BASIC PREMISES Premise one We can write the number 1 in very different ways 2 2 1 km 1 km 1 = = = = 1+1 1 km 1000 m 2 If you have two quantities that are equal, and you divide one by the other, you end up with a value equaling 1. Premise two A number can be multiplied by 1 and not change that number 2 2 1 km 1 km 4 x 1 = 4 x = 4 x = 4 x = 4 x = 4 1+1 1 km 1000 m 2 U.0_3_4 d12
Conversion Factor Method Applying the premises to the example : 10 3 mL V = 1.3 L = 1.3 L x 1 = 1.3 L x = 1.3 L x = 1 L 1 L Premise two: A number can be multiplied by 1 and not change that number Premise one: We can write the number 1 in very different ways If you have two quantities that are equal, and you divide one by the other, you end up with a value equaling 1. 1 L = 10 3 mL Unit equation 10 3 mL = 1.3 L x = 1.3 x 10 3 mL 1 L U.0_3_4 d13
A « Unit equation » shows the mathematical relation between base units Conversion Factor Method A « Unit equation » shows the mathematical relation between base units 1 m = 10 2 cm Unit equation A 1 cm = 10 -2 m Unit equation B U.0_3_4 d14
Exercise : Write or complete the following unit equations: Conversion Factor Method Exercise : Write or complete the following unit equations: 1 L = 10 3 mL Unit equation a) 1 km = ___m. b) 1 hg = ___ g. c) 1 kL = ___ L. d) 1 __g = 10-3 g. e) 1 mes = __ días f) 1 h = ____ s U.0_3_4 d15
Exercise : Write or complete the following unit equations: Conversion Factor Method Exercise : Write or complete the following unit equations: 1 L = 10 3 mL Unit equation a) 1 km = 103 m. b) 1 hg = 102 g. c) 1 kL = 103 L. d) 1 mg = 10-3 g. e) 1 mes = 30 días f) 1 h = 3600 s U.0_3_4 d16
Create the conversion factor : Conversion Factor Method Create the conversion factor : If you have two quantities that are equal, and you divide one by the other, you end up with a value equaling 1. From one unit equation: 1 L = 10 3 mL You can divide one quantity by the other in two different ways, so that you end up with a value equaling 1. 10 3 mL 1 L = 1 = 1 1 L 10 3 mL Two conversion factors U.0_3_4 d17
From one unit equation: Two conversion factors: Conversion Factor Method Write two conversion factors for each of the following unit equations, as in the example: From one unit equation: 1 L = 10 3 mL Two conversion factors: 1 L 10 3 mL 1 L 10 3 mL a) 1 km = 103 m. b) 1 hg = 102 g. c) 1 mg = 10-3 g. d) 1 h = 3600 s U.0_3_4 d18
From one unit equation: Two conversion factors: Conversion Factor Method Write two conversion factors for each of the following unit equations, as in the example: From one unit equation: 1 L = 10 3 mL Two conversion factors: 1 L 10 3 mL 1 L 10 3 mL a) 1 km = 103 m. b) 1 hg = 102 g. 10 3 m 1 km 10 2 g 1 hg 1 km 10 3 m 1 hg 10 2 g d) 1 h = 3600 s c) 1 mg = 10-3 g. 3600 s 1 h 10 -3 g 1 mg 3600 s 1 mg 10 -3 g 1 h U.0_3_4 d19
Conversion Factor Method Write two conversion factors for each of the following metric relationships: (a) kilometers and meters (b) grams and decigrams: U.0_3_4 d20
Conversion Factor Method Write two conversion factors for each of the following metric relationships: (a) kilometers and meters (b) grams and decigrams We start by writing the unit equation to generate the two conversion factors: (a)The prefix kilo-means 1000 basic units; thus, 1 km = 1000 m. The two conversion factors are: U.0_3_4 d21
Conversion Factor Method Write two conversion factors for each of the following metric relationships: (a) kilometers and meters (b) grams and decigrams We start by writing the unit equation to generate the two conversion factors: (b)The prefix deci-means 0.1 basic unit; thus, 0.1 g = 1 dg or 1 g = 10 dg The two unit factors are: U.0_3_4 d22
Conversion Factor Method Write two conversion factors for each of the following metric relationships: (a) liters and milliliters (b) megaseconds and seconds Answers: (a)1 L/1000 mL and 1000 mL/1 L (b)1 Ms/1,000,000 s and 1,000,000 s/1 Ms U.0_3_4 d23
Conversion Factor Method (Revising) U.0_3_4 d24
Conversion Factor Method (Revising) U.0_3_4 d25
Conversion Factor Method (Revising) 103 1 102 105 103 103 U.0_3_4 d26
Conversion Factor Method (Revising) U.0_3_4 d27
Conversion Factor Method (Revising) 103 103 103 106 U.0_3_4 d28
Conversion Factor Method (Revising) U.0_3_4 d29
Conversion Factor Method Now we are ready to use the Unit Factor Method or Conversion Factor Method to perform unit conversions U.0_3_4 d30
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in liters? Strategy Plan: Step 1:What unit is asked for in the answer? Step 2:What given value is related to the answer? Step 3:What conversion factor should we apply? Given that 1 L = 10 dL, the two conversion factors are: U.0_3_4 d31
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in liters? Strategy Plan: Unit Analysis Map: We apply the conversion factor 1 L/10 dL to cancel deciliters 1 L 1 L V = 125 dL = 125 dL x = 125 dL x = 12.5 L =1.25 x 101 L 10 dL 10 dL U.0_3_4 d32 The given value, 125 dL, limits the answer to three significant digits.
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in milliters? Strategy Plan: Step 1:What unit is asked for in the answer? m Step 2:What given value is related to the answer? Step 3:What conversion factors should we apply? Given that 1 L = 10 dL, and 1 L = 1000 mL, the two pairs of conversion factors are: dL to L L to mL U.0_3_4 d33
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in milliters? Strategy Plan: Unit Analysis Map: Conversion factor 1 changes dL to L and cancels dL Conversion factor 2 changes L to mL and cancels L U.0_3_4 d34
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in milliters? Strategy Plan: Unit Analysis Map: dL to L Cancels dL 1 L V = 125 dL = 125 dL x 10 dL U.0_3_4 d35
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in milliters? Strategy Plan: Unit Analysis Map: L to mL Cancels L 1 L 103 mL V = 125 dL = 125 dL x x = 101 dL 1 L U.0_3_4 d36
Conversion Factor Method A hospital has 125 deciliter bags of blood plasma. What is the volume of plasma expressed in milliters? Strategy Plan: Unit Analysis Map: 1 L 103 mL 103 mL 1 V = 125 dL = 125 dL x x = 125 x x = 101 dL 1 L 101 1 = 125 x 10-1 x 103 mL = 125 x 10 (-1+3) mL = 125 x 10 2 mL = = 1.25 x 10 4 mL U.0_3_4 d37
Conversion Factor Method Convert 3.5 km to millimeters Strategy Plan: Step 1:What unit is asked for in the answer? Step 2:What given value is related to the answer? Step 3:What conversion factors should we apply? km to m m to mm U.0_3_4 d38
Conversion Factor Method Convert 3.5 km to millimeters Strategy Plan: Unit Analysis Map: Conversion factor 1 changes km to m and cancels km Conversion factor 2 changes m to mm and cancels m U.0_3_4 d39
Conversion Factor Method Convert 3.5 km to millimeters Strategy Plan: Unit Analysis Map: km to m Cancels km 103 m L = 3.5 km = 3.5 km x 1 km U.0_3_4 d40
Conversion Factor Method Convert 3.5 km to millimeters Strategy Plan: Unit Analysis Map: m to mm Cancels m 103 m 1 mm L = 3.5 km = 3.5 km x x = 1 km 10-3 m U.0_3_4 d41
Conversion Factor Method Convert 3.5 km to millimeters Strategy Plan: Unit Analysis Map: 103 m 1 mm 1 L = 3.5 km = 3.5 km x x = 3.5 x 103 x mm = 1 km 10-3 m 10-3 = 3.5 x 103 x103 mm = 3.5 x 106 mm U.0_3_4 d42
Conversion Factor Method The mass of Earth is 5.98 × 1024kg. What is the mass expressed in megagrams? Strategy Plan: Step 1:What unit is asked for in the answer? Step 2:What given value is related to the answer? Step 3:What conversion factors should we apply? U.0_3_4 d43
Conversion Factor Method The mass of Earth is 5.98 × 1024kg. What is the mass expressed in megagrams? Strategy Plan: Unit Analysis Map: Conversion factor 1 changes kg to g and cancels kg Conversion factor 2 changes g to Mg and cancels g U.0_3_4 d44
Conversion Factor Method The mass of Earth is 5.98 × 1024kg. What is the mass expressed in megagrams? Strategy Plan: Unit Analysis Map: m= U.0_3_4 d45
Conversion Factor Method (Revising) U.0_3_4 d46
Conversion Factor Method (Revising) U.0_3_4 d47
Conversion Factor Method (Working with fractions) If a car is traveling at 95 km/h, what is the speed in meters per second (given that 1 km = 1000 m, and 1 h = 3600 s)? Strategy Plan: Step 1:What unit is asked for in the answer? Step 2:What given value is related to the answer? Step 3:What conversion factors should we apply? km to m h to s U.0_3_4 d48
Conversion Factor Method (Working with fractions) If a car is traveling at 95 km/h, what is the speed in meters per second (given that 1 km = 1000 m, and 1 h = 3600 s)? Strategy Plan: Unit Analysis Map: Conversion factor 1 changes km to m and cancels km, which is in the numerator Conversion factor 2 changes h to s and cancels h, which is in the denominator U.0_3_4 d49
Conversion Factor Method (Working with fractions) If a car is traveling at 95 km/h, what is the speed in meters per second (given that 1 km = 1000 m, and 1 h = 3600 s)? Strategy Plan: Unit Analysis Map: v= U.0_3_4 d50
Conversion Factor Method (Working with square units) U.0_3_4 d51
Conversion Factor Method (Working with square units) Strategy Plan: Step 1:What unit is asked for in the answer? Step 2:What given value is related to the answer? Step 3:What conversion factors should we apply? cm to m Cancels cm cm to m Cancels cm U.0_3_4 d52 =
Conversion Factor Method (Working with square units) Strategy Plan: Unit Analysis Map: cm to m Cancels cm Conversion factor 1 changes cm to m and cancels cm Conversion factor 2 changes cm to m and cancels cm U.0_3_4 d53
Conversion Factor Method (Working with square units) Strategy Plan: Unit Analysis Map: cm to m Cancels cm L = 3 cm2 = = 3 cm x cm x 10-2 m 1 cm U.0_3_4 d54
Conversion Factor Method (Working with square units) Strategy Plan: Unit Analysis Map: cm to m Cancels cm L = 3 cm2 = = 3 cm x cm x 10-2 m 10-2 m x 1 cm 1 cm U.0_3_4 d55
Conversion Factor Method (Working with square units) Strategy Plan: Unit Analysis Map: L = 3 cm2 = = 3 cm x cm x 10-2 m 10-2 m x = 3 x10-2 x10-2 m2 = 3 x10(-2-2) m2 = 1 cm 1 cm = 3 x10-4 m2 U.0_3_4 d56
Conversion Factor Method (Working with cubic dimensions) U.0_3_4 d57
Conversion Factor Method (Proposed exercices) U.0_3_4 d58
Conversion Factor Method (Proposed exercices) U.0_3_4 d59