Studying Science

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Studying Science

• Means observing the world around you and then
  trying to find ways to explain it

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You might ask ?s like

• Why is the sky blue?
• Why does soda tickle your nose?
• How does a bird navigate during migration?
• How does a pulley system make a heavy load
  lighter?

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Sohow do we answer these questions?

• What do we DO while studying science?
• Hypothesize
• Interpret
• Experiment
• Understand
• Observe
• Document
• Share
• Calculate

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What is chemistry??

• Chemistry is the study of how and why stuff
  appears and behaves as it does.
• Why does it look the way it does?
• Why does it react with other stuff?
• How does it react with other stuff?

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What is a chemical?

• Any substance formed or used during a chemical
  reaction.
• Salt
• Bleach
• Acid
• Almost everything is a chemical!

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How do we learn about chemistry?

• Observe!
• All substances have two kinds of properties we
  can observe
• Physical Properties
• Chemical Properties

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Physical Properties

• Can be observed or measured without changing the
  composition of a substance (you dont have to
  change what it is)
• Color
• Texture
• Odor
• Density
• Melting point
• Boiling point

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Chemical Properties

• Tell how a substance interacts with other
  substances
• Does it react with acid?
• Does it react with base?
• Does it burn?
• Does it react with anything?

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Physical Changes

• Are changes that do not affect chemical
  composition. They dont change what the
  substance is.
• Melting
• Boiling
• Freezing
• Crushing
• Breaking
• Squishing

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Chemical Changes

• Substance is changed into something new
• Occurs at the atomic level
• Atoms are rearranged

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Signs of Chemical Changes

• Reacting with acid
• Reacting with base
• Bubbling
• Change in temperature
• Precipitate forms
• Burning
• Change in color

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Precipitate -

• Describes the formation of a solid during a
  chemical reaction
• Usually from two solutions being combined
• Liquid turns cloudy or floaters appear

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States of Matter

• States are an important physical property
• There are 3 main states
• Solid
• Liquid
• Gas

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Solid

• Atoms/molecules held close together
• Very little freedom to move (low energy)
• Fixed volume and shape

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Liquid

• Atoms/molecules held close together
• More freedom to move than solid (medium energy)
• Fixed volume, variable shape (takes shape of
  container)

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Gas

• Atoms/molecules far apart
• Great freedom to move (high energy)
• Variable volume and shape (expands to fill any
  container)

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Phase Changes

• Important physical changes
• Freeze/melt change between liquid and solid
• Evaporate/condense change between liquid and
  gas
• Sublimate/deposit change between solid and gas

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Phase Change Cheeseburger
Sublime
Evaporate
Melt
Solid
Liquid
Gas
Freeze
Condense
Deposit