Scientific Method

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Scientific Method
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What is Science?

• Science is a method for studying the natural
  world.
• It is a process that uses observation and
  investigation to gain knowledge about events in
  nature.

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Scientific Method

• An organized set of investigation procedures is
  called a scientific method.
• Six common steps found in scientific methods are
  shown.

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Controlled Experiment

• Variables factors in an experiment that can be
  changed.
• Independent Variable The variable that you
  change in the experiment (the amount of
  fertilizer used).
• Dependent Variable the variable that may change
  due to the independent variable (growth in the
  height of the plant).

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Controlled Experiment (2)

• Control Group A group that is not changed in an
  experiment (one plant that is not fertilized).
• Experimental Group A group in an experiment
  that has had one variable changed (The plants
  that were given fertilizer).
• Constants A factor that does not change when
  other variables change (type of plant, type of
  fertilizer, amount of sunlight, size of the pots).

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Measurement

• Quantitative information (qualitative data would
  be descriptions of your observations).
• Measurements represent quantities (something that
  has magnitude, size, or amount).

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SI Measurement

• Scientist use the International System of Units
  (SI).

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SI Base Units

• There are seven SI base units (meter, kilogram,
  second, kelvin, mole, ampere, candela). All
  other SI units are derived from these.
• Mass is the measure of the quantity of matter (SI
  unit is the kilogram). Measured by using a
  balance. Weight is a measure of the
  gravitational pull on matter and is measured by
  using a spring scale.
• The SI unit for length is the meter.

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Derived SI Units

• Derived units are produced by multiplying or
  dividing standard units.
• The SI unit for volume is m3 (1mL
  1cm3)

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Derived SI Units (2)

• Density is the ratio of mass to volume, or mass
  divided by volume (D m/v). The SI unit for
  density is kg/m3. In the lab you will usually
  see density expressed as g/mL or g/cm3.

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Conversion Factors

• Ratio derived from the equality between two
  different units that can be used to convert from
  one unit to another.
• Example
• In one dollar there are 4 quarters
• 4 quarters or 1 dollar
• 1 dollar 4 quarters

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Scientific Notation

• Numbers are written in the form M x 10n, where
  the factor M is a number greater or equal to 1
  but less than 10 and n is a whole number.
• 65,000 km 6.5 x 104 km (when numbers are
  written in scientific notation only significant
  figures are shown).
• 0.00012 mm 1.2 x 10-4 mm

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Scientific Notation (2)

• M is determined by moving the decimal point in
  the original number to the left or the right so
  that only one nonzero digit remains to the left
  of the decimal point.
• n is determined by counting the number of places
  that you moved the decimal point. If you moved
  it to the left, n is positive. If you moved it
  to the right, n is negative.

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Organizing Data

• A graph is a pictorial representation of
  information recorded in a data table. It is used
  to show a relationship between two or more
  factors.

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Types of Graphs

• Line graphs are best for displaying data that
  changes. It best shows the relationship between
  two variables. A variable is anything that can
  change in an experiment. Line graphs are made
  with the x-axis showing the independent variable
  (manipulated variable) and the y-axis showing the
  dependent variable (responding variable).

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Types of Graphs (2)

• Bar graphs are best for comparing data for
  several individual items or events. Bar graphs
  use a series of columns to display data.

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Types of Graphs (3)

• Pie charts are best for displaying data that are
  parts of a whole.

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Density

• Density is a physical property of a substance.
  Physical properties can be observed or measured
  without changing a substance.
• Other physical properties of substances include
  shape, color, odor, and texture.

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Calculating Density

• Density is calculated by dividing an objects
  mass by its volume.
• Density mass/volume or
• D m/v

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Low and High Density

• A substance with a low density is referred to as
  being light. An example is Styrofoam.
• A substance with a high density is referred to as
  being heavy. An example is iron.
• Density of a liquid is reported in grams per
  milliliter (g/ml) and a solid is reported in
  units of grams per cubic centimeter (g/cm3).