unit 1 and 2

Section 1 | The Scientific Method

The scientific method is a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data.

\ Observing and collecting data

• Observing is useing the five senses in order ot get information
• data may be   * qualitive (ex. the color of a cake)   * quantative (ex. counting the amount of birds in a flock)
• A system is an amount of matter in a space that is chosen to be studied   *

Formulating Hypotheses

• Scientists make generalizations based on data
• They use this to make a hypothesis or a testable statement   * ex. If I add phosphorus fertilizer then the plant will grow faster over the course of 25 days

Testing Hypotheses

• Testing a hypothesis requires an experiment in order to support or refute a hypothesis
• Controls are the experimental conditions that remain constant
• Variables are any experimental conditions that change

Theorizing

• A model is more than a physical object in science and can be an explanation of how phenomena occur and how data or events are related   * visual verbal or mathmatical   * ex. atomic model of matter
• A theory is a broad generlization that explains a body of facts of phenomena   * ex. atomic theory

\ Section 2 | Units of Measurement

• Measurement represent qualities
• A quantitiy is something that had magnitude, size, or amount
• Measurement does not equal quantity   * a teaspoon is a unit of measurement   * volume is a quantity
• The choice of unit depends on the quantity being measured

SI Measurement

• Scientists have created a system called SI
• SI has 7 units   * most other units are deried from the 7
• Mass   * Mass is the quantity of matter   * The SI unit for mass is kilogram   * Weight is the measure of gravitational pull on matter   * Mass does not rely on gravity
• Length   * Length is a measure of distance   * The SI standard for length is the meter   * Kilometers or km is used to express longer distances   * Centimeters or cm is used to express shorter distances

\ \ Derived SI units

• Volume   * The amount of space occupied by an object   * The derived SI unit is cubic meters   * The cubic centimeter is used   * Liters is a non-SI unit   * 1 L = 100 cm^3   * 1 mL = 1 cm^3
• Density   * density is the ratio of mass to colume or mass divided by colume   * density = mass/volume   * the derives SI unit is kilograms bper cubic meter   * Density is a characteristic physical property of a substance   * \

SI units are added to units to express larger and smaller unit values

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