Chapter 1: The Nature of Science

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Chapter 1 The Nature of Science
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What is Science?

• Life, Earth and Physical Science

Matter and Energy
Living things
Chemistry
Earth and Space
Physics
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Steps to the Scientific Method

• Observation ? a question
• Gather Info
• Hypothesis a tentative answer
• Experiment test the hypothesis
• Conclusion

If doesnt work
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Variables and Constants

• Variable - Things that are changing
• Constants Things that are NOT changing
• Control A test that is left alone. Nothing is
  done in this test.

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Conclusions

• Scientific law describes how nature behaves.
  Normally is always true.
• Theory explains why nature behaves in the way
  described by the law. Predicts results of
  further experiments.

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Now Lets use this Method

• Observation ? a question
• Gather Info
• Hypothesis a tentative answer
• Experiment test the hypothesis
• Conclusion

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Whats in Frankensteins Head??

• Read the handout
• Record your observations
• Draw a diagram of your model
• Have your final model approved
• Answer final questions

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Standards of Measurement

• Chapter 1 Section 2

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Units and Standards

• Standard an exact quantity used to compare
  measurements
• Keeps consistent measurements

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Measurement Systems

• Measurement NUMBER and UNIT
• SI Units (Systeme Internationale dUnites)
• Agreed throughout the world
• Standards kept in France
• 7 base units

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SI Base Units




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Using SI Prefixes (attach prefix to a base unit)
Prefix Symbol Value
Kilo- k 1000 bases 1k
Deci- d 1 base 10 d
Centi- c 1 base 100 c
Milli- m 1 base 1000 m
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Practice with Units

• Put 1 with the bigger unit
• Kilo bigger than base
• Deci, centi, milli smaller than base
• ___ m ___ km
• ___ s ___ ms
• ___ g ___ dg

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Distance/Length Units

• Meter little bigger than yard (3 feet)
• Kilometer smaller than mile
• 1 mi 1.6 km
• Centimeter smaller than inch
• 1 in 2.54 cm
• Millimeter 10 mm 1 cm

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Volume Units

• Volume amount of space occupied by object
• Liquids liters (L)
• 1 L 1000 mL
• Solids cubed length units
• L x W x H ? m x m x m m3
• 1 cm3 1 mL

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Mass Units

• Mass amount of matter stuff
• gram paperclip
• 1 kg 2.2 lb

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Time Units

• Years, days, hours, minutes, seconds

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Temperature Units

• Celsius 0oC Freezing water
• 100oC Boiling water
• Kelvin coldest possible temperature is 0K
  absolute zero
• 0K -273oC
• K oC 273

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Converting Units

• Convert to find equivalent in another unit
• Identify whats given
• Identify conversion factor
• Carry out conversion WITH UNITS!!

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Conversion factors

• A ratio of equivalent measurements.
• Start with two things that are the same.
• 1 m 100 cm
• Can divide by each side to come up with two ways
  of writing the number 1

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Conversion factors

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Conversion factors
1 m
1

100 cm
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Conversion factors
1
1 m

100 cm
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Conversion factors
1
1 m

100 cm
100 cm

1
1 m
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Conversion Factors

• Unique way of writing the number 1.
• Does NOT change the VALUE, it changes the UNITS.

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Write the conversion factors for the following

• kilograms to grams
• milliseconds to seconds

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Lets Try Some!

• 323 mm _____ m
• 3.2 miles _____ km
• 250 L _____ mL
• 15 kg _______ dg

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Derived Units

• Def a unit formed by combining other units
• Ex m3, m2, mi/hr, etc.

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Density

• Density Mass
• Volume
• SI Unit?
• Normally use g/cm3
• Factor in buoyancy

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Density

• If a metal block has a mass of 65.0 grams and a
  volume of 22 cubic centimeters, what is the
  density of the block?

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Finding Volume

• Aluminum has a density of 2.7 g/cm3. What volume
  of aluminum has a mass of 60 grams?

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Finding Mass

• Gold has a density of 19.3 g/cm3. A block of
  gold has a volume of 18 cm3, what is the mass?