Science in Our World

Measurement

Fact: an observation that has been repeatedly confirmed and is accepted as true.

Theory – explanation for hypothesis and observations that have been supported by testing, it explains and predicts

Law – summary of many experimental results and observations, tells you how things work

Vocabulary

Scientific Models

A model is a substitute or stand-in for what you are actually studying or trying to predict. They are convenient. Models are similar to what they represent even if they are not exact:

• can be larger or smaller• can be different colors• may not act the same• they do have limitations!

.

Types of Models

Physical Models- look like the objects they are modeling.

Ex. A globe is a physical model of the earth.

Mathematical Models– made up of mathematical equations and data.Ex. Newton’s Law in Physics.

Types of Models

Conceptual Models – system of ideas, groupings, or classification. Ex. Kingdoms and

Domains.

Measurement

International System of Units (SI System)• Metric System• Used all over the World• Improves communication between scientists

KHD_M_DCM modelMnemonic!King Henry Dances Merrily Down Central Main

LazilyGracefully

K H D_M_D C M model

Mnemonic!King Henry Dances Merrily Down Central Main

LazilyGracefully

The others are prefixesK = Kilo = x1000H = Hecto = x100D = Deka = x10

d = deci = x .10c = centi = x .100m = milli = x .1000

Base Units ChangeM = metersL = litersG = grams

Measurement

LengthSI Unit - meter

AreaHow much surface an object hasArea = Length x Width

= square units = cm2, m2, km2

L

W

Measurement

LW

H

VolumeAmount of space something occupies or amount

of space something takes up

Volume of a rectangular prism

Volume = Length x Width x Height = cubic units = cm3, m3, km3

Volume of irregular shaped objects?

Measurement

Volume of irregular shaped objectsAmount of space something occupies or

amount of space something takes up

Volume = Amount of water the object displaces= cubic units = mL3, L3

Ex. A graduated cylinder has a water level of 200 mL. A rock is dropped into the graduated cylinder and displaces the water up to 300 mL. What is the volume of the rock?

300 mL – 200 mL = 100 ml3

Measurement

MassAmount of matter in an object.Usually measured in kilograms (large items)

or grams (small items)

Which has more mass, a kilogram of feathers or a kilogram of bricks?

Measurement

Weight

The pull of gravity on an object or how heavy something is.

Usually measured in kilograms (large items) or grams (small items)

Where do you weigh more, Earth or the moon?

Measurement

Density

A physical property that describes the mass per unit volume of a substance.

Mnemonic – Density is a “broken heart”.

D = ---------- or Density = -------------- D = ---------- or Density = -------------- MassVolume

MeasurementTemperature

Measure of how hot or cold an object isExpressed as degrees Fahrenheit,

degrees Celsius, or Kelvin (SI)

• Water boils at 212° F and 100° C• Water freezes at 32° F and 0° C• Body temperature is about 98.6° F