Measurement-A Common Language

Density, Time, & Temperature

Density

Density / Densidad

• The measure of how much mass is contained in a given volume. / Es la medida de cuanta masa esta contenida en un volumen específico.

The formula of density is: / La formula para densidad

es:

Density = Mass / VolumeDensidad = Masa / Volumen

Comparing Densities - Inferring: Which item has the greater density? Comparando densidades – Infiriendo: Cual objeto tiene la mayor densidad?

• The bowling ball / La pelota de Bolear

• Since the bowling bowl has a greater mass, it has a greater density, even though both balls have the same volume. / Debido a que la pelota de bolear tiene la mayor masa esta tiene la mayor densidad. Auque ambas tienen el mismo volumen.

Density / Densidad

Units of Density / Unidades de densidad

Why is density expressed as a combination of two different units? Porque la densidad es expresada

como una combinación de dos unidades diferentes?

• Because density is actually made up of two other measurements – mass and volume – an objects density is expressed as a combination of two units / La densidad esta contituida por dos otras medidas la masa y el volumen, por lo tanto la densidad se expresa como una combinacion de las dos.

Two Common Units For Density / Dos unidades

comunes para densidad.

• Grams per cubic centimeter (g/cm³) / Gramos por centimetro cúbico (g/cm³)

• Grams per milliliter (g/mL) / Gramos por mililitro (g/mL)

Math Practice: Práctica matemática: What is the density of a wood block with a volume of 125 cm³ and a mass of 57 g? Cual es la densidad de un bloque de madera con un volumen de 125 cm³y una masa de 57 g?

Density = mass / volume /Densidad = masa / volumen

Density = 57 g / 125 cm³Densidad = 57 g / 125 cm³

Density = 0.46 g/ cm³Densidad = 0.46 g/ cm³

Math Practice: What is the density of a liquid with a mass of 45 g and a volume of 48 mL? Prática matemática: Cuál es la densidad de un liquido con una masa de 45 g y un volumen de 48ml?

Density = mass / volumeDensidad = masa / volumen

Density = 45 g / 48 mLDensidad = 45 g / 48 mL

Density = 0.94 g/mLDensidad = 0.94 g/mL

Density / Densidad

Densities of Common Substances / Densidades de

sustancias comunes

The density of a substance is the ______for all samples of that substance. / La densidad de una sustancia es la _____ para todos las muestras de esa subtancia.

• Same / Misma

An object will float if it is _____ _____ than a surrounding liquid. / Un objeto flota si es _____ _____ que el liquido circundante.

• Less dense / menos denso

Figure 6: Applying Concepts: How could you use density to determine whether a bar of metal is pure gold? • If the bar of gold

has a density that is greater than or less than 19.3 g/cm³, then the sample is not pure gold.

Densities of Some Common

Substances

Substance

Density(g/cm³)

Air 0.001

Ice 0.9

Water 1.0

Aluminum 2.7

Gold 19.3

Reading Checkpoint (page 53): Will an object with a density of 0.7 g/cm³ float or sink in water?

• An object that has a density of 0.7 g/cm³ will float in water (1 g/cm³) because it is less dense than water

Time

Time

Units of Time

What is the SI unit used to measure time?

• The second(s) is the SI unit to measure time

Common Conversions for Time

1s =

= 60 s

1h =

Common Conversions for Time

1s = 1,000 ms

= 60 s

1h =

Common Conversions for Time

1s = 1,000 ms

1 min = 60 s

1h =

Common Conversions for Time

1s = 1,000 ms

1 min = 60 s

1h = 60 min

Time

Measuring Time

Why would a stop watch be used to measure time in an important race?

• Because stop watches measure in units smaller than the second

• These measurements include the tenth and hundredth of a second

Reading Checkpoint (page 53) - How many milliseconds are in one second? • 1,000 milliseconds

Temperature

Temperature

Units of Temperature

A common unit to measure temperature is the ___ ___.

• Celsius scale

Water freezes at ______ and boils at ______.

• 0 °C• 100 °C

The normal human body temperature is approximately ________.

• 37 °C

What is the official SI unit for temperature?

• The Kelvin Scale (°K)

• 0 °K = 273 °C

Figure 8: Measuring Temperature - Observing: At what temperature on the Kelvin scale does water boil?

• 373 °K

What is absolute zero?

• Absolute zero is considered by scientists to be the coldest temperature possible

• 0 °K or –273 °C

Temperature

Measuring Temperature

What instrument is used to measure temperature?

• Thermometer