Sponge: List five scientists you saw in the Mechanical Universe film.
These two overlap; the main difference is that physics always deals with the concept of energy.
mechanics, thermodynamics, waves, optics, electricity and magnetism, relativity, and nuclear physics. The major areas within Physics are:
Scientific MethodLAWS-describe the relationships between various phenomena
Boyle’s Law • Charles’ Law • Cole’s Law
Scientific Law-expressed by wordsLaws in physics-expressed by math equations
Theories often involve models.e.g. Atomic Theory Democritus’ Model Thomson’s Model Rutherford’s Model Bohr’s Model Electron Cloud Model
Hypotheses & InvestigationsFive Steps Problem Research Hypothesis - extends thinking beyond known facts Experiment Conclusions
Certainty in scienceOne should always question the validity of scientific Laws, Theories, or Hypotheses.
METRIC SYSTEM - uses a decimal basis for multiples and fractions of the basic units of measure.
International System of UnitsThe SI system(Systeme International d’Unites)
Units of measure are used to describe physical quantities.e.g. the meter is the unit of length
Seven fundamental units of measure: • 1. length meter • 2. mass kilogram • 3. time second • 4. electric current ampere • 5. temperature kelvin • 6. amount of substance mole • 7. luminous intensity candela
Combinations of these units are used to measure other physical quantities.(e.g. mass density)These are called derived units.
Modern metric system often called the MKS system.(meter, kilogram, second)
METERStandard meter was a metal bar until 1960.Now 1 meter = the distance light travels in a vacuum in 1/299 729 458th of a second. (speed of light is no longer subject to revision)
KILOGRAMMass of the standard kilogram. Only measure that still is a natural object.
FORCE AND WEIGHTNewton is the accepted unit.Force needed to accelerate a one kilogram mass by one m/s2.
THE SECONDone second = 9 192 631 770 vibrations of cesium-133 atoms.
1 ml H2O = 1 cm3 H2O = 1 g H2Oheat required to change temp of 1 g liquid H2O 1° centigrade (Kelvin) is 1 calorie
It is important to indicate the degree of uncertainty in measurements so far as it is known.
ACCURACY - the closeness of a measurement to the accepted value for a specific physical quantity.
absolute error- actual difference between the accepted value and the measured value.
Ea = |O - A|,whereEa is the absolute error, O is the observed value, and A is the accepted value.
Relative Error - expressed as a percentage. (often called percentage error)
Er = (Ea / A) x 100%whereEr is the relative error, Ea is the absolute error, and A is the accepted value.
PRECISION - the agreement among several measurements that have been made in the same way.
Absolute deviation-difference between a single measured value and the average of several measurements made in the same way.
Relative Deviation-the percentage average deviation of a set of measurements.
Significant Figures - Those digits in a number that are known with certainty plus the first digit that is uncertain.
2. All zeros between nonzero figures are significant108.005____sig figs
3. Zeros right of a nonzero figure, but left of understood decimal point, are not significant unless indicated.109 000 _____ sig figs _109 000 _____ sig figs
3. Zeros right of a nonzero figure, but left of understood decimal point, are not significant unless indicated.109 000 Three sig figs _109 000 _____ sig figs
3. Zeros right of a nonzero figure, but left of understood decimal point, are not significant unless indicated.109 000 _____ sig figs _109 000 Five sig figs
4. Zeros to the right of a decimal point but to the left of a nonzero figure are not significant. Zero to the left of decimal point is never significant.0.000 647 _____sig figs
4. Zeros to the right of a decimal point but to the left of a nonzero figure are not significant. Zero to the left of decimal point is never significant.0.000 647 Three sig figs