Physical Science Waves

Electromagnetic Waves- electric and magnetic field that are perpendicular to each other.

• transverse waves
• do not need a medium
• light is a EM wave
• light is a combination of a wave and particle
• photon- packet of energy/ particle that carries energy.
• waves will travel as long as there is energy to carry

wave speed = frequency x wavelength

• wave speed (ws) is measured in m/s
• frequency (f) is measured in hertz
• wavelength is measured in meters
• the speed of a light wave is a constant in a vacuum (symbol "c") is 300.000 km/s
• speed of a EM wave will decrease as it enters a more dense medium
  
• the higher frequency EM waves will have short wavelengths, low frequency will have longer wavelengths.
• gamma rays have the the shortest wavelength/ highest frequency.
• EM spectrum ( low frequency to high)- radio, infrared, visible, x-ray, gamma.
  

Chem Chap 3 Review

Standard Metric Units

• mass- kilogram, kg
• volume- liter, L
• length- meter, m
• time- second, s
• temperature - Kelvin, K- neat thing about Kelvins no negative values, cannot get colder than absolute zero.

Weight- is the pull of gravity on an objects mass, therefore weight is dependent on gravity. Another way to look at this is an objects position, location, from a source of gravity. Farther away from gravity object will weigh less.

Density- is an intensive property of the object, that is it does not depend on the "amount" of the object. D=mass/volume. Be sure you can calculate for any variable in the density formula. Refer back to your worksheet for problems.

Factor-Label Method- be sure to review this. 100cm= 1m, therefore it also can be written:
1m/100cm or 100cm/1m.

Scientific notation

• when moving decimal to the right- negative exponent
• when moving decimal to the left- positive exponent
• after moving decimal only one number to the left of the decimal point.
• when multiplying add exponents, dividing subtract
  

ex: 0.0000045 4.5 x10 -6
450000 4.5 x10 5 ( -6 and 5 are exponents)
3 x 10 3 X 4 x 10 -6 12 x 10 3 +(-6) 12 x 10 -3 1.2 x 10 -2
8 x 10 4 / 2 x 10 -5 4 x 10 4 - (-5) 4 x 10 9

Significant Figures

Refer to rules in your notebook. In multiplication and division your answer can only have as many sig figs as the least precise number ( lowest number of sig figs)

ex. 0.001 1 SF
0.00100 3 SF
0.001001 4 SF
100 1 SF
101 3 SF
101.0 4 SF

Physical Science Review

For the test Friday be sure to review:

• your packet on Topographic Maps.
• diagrams of solar and lunar eclipses
• how to calculate speed
• scientific notation
• factor-label conversions
• metric relationships
• Newton's Laws of Motion
• difference between mass and weight
• rotation- spinning on axis, causes night and day
  
• revolution- orbit around the Sun
• cause of the seasons- tilt of the Earth on its axis
  

Famous astronomers:

• Ptolemy- proposed the geocentric model of the universe
• Copernicus- given credit for the heliocentric model of the solar system
• Galileo- inventor of telescope
• Kepler- discover elliptical shape of planetary orbits.
• Newton- discovered forces that keep planets in orbits

Moon Info

• period of rotation and revolution are the same- 27 1/3 days
• moon has no atmosphere therefore, no weathering, craters are present
• age of moon is the same age as the Earth
• waxing- new to full moon
• waning- full to new moon
• takes the moon about 4 weeks to go through a full cycle
  

Chemistry Test Review

Chemistry is the study of the composition and structure of matter. Chemistry studies the changes of matter- one can use the scientific method to study these changes in matter.
Energy changes are NOT changes in matter.
After observing a series of experiments a chemist can develop a THEORY to explain these observations.

Matter has two general types of properties:
1. extensive- "how much" such as mass and volume
2. intensive- does not depend on how much such as density.

Physical properties include- melting point, hardness, color, evaporation .
Chemical properties depend on how the substance combines with other substances: rusting, combining with oxygen.

States of Matter

Solid- definite shape and volume
Liquid- definite volume, takes the shape of its container/ indefinite shape.
Gas- indefinite volume, fills its container, easy to compress, expands when heated.
Vapor- gas phase of a substance that typically a solid or gas at room temperature.

Mixture- a blend of substances which are "easily separated".
Homogeneous mixture- same throughout, not chemically combined, "stainless steel".
Heterogeneous mixture- not the same throughout, soil, Italian salad dressing.

Chemical compound- substances that are chemically combined, can only be separated by chemical means.

During a chemical reaction matter is NOT created or destroyed, only changed.

Physical Science Wed Stuff

Density is an intensive (does not depend on amount) property of the object.

Density = mass/volume, typically units are g/ml

Algebra
The old standby "Cross Multiply and Divide". This can be used when you have two ratios equal to each other.

a/b=c/d

Step 1- Cross multiply numerator on the left side x denominator on the right. In our example (ad)

Cross multiply denominator on the left side x numerator on the right. In our example (bc)


So we get ad=bc

Let's solve for the four variables.

Step 2 - Divide,

Solving for a ad/d= bc/d ------> a= bc/d

Solve for d ad/a= bc/a -------> d= bc/a

Solve for b ad/c = bc/c -------> ad/c = b

Solve for c ad/b = bc/b --------> ad/b = c

Scientific Method Phy Sci/ Chemistry

Credit: Stinger Bee Science

Chem and Phy Sci- Graphing

Lee Marek 1. Use graph paper (home-made graph paper is unacceptable) ink or pencil. Better yet do it on Excel, other spread sheet programs or some graphing program.

2. Plan ahead! Note the largest value number to be plotted on each axis and make sure your scale is large enough so that you use up at least half of the paper in both directions.

3. Label the axis and give units to those labels in parenthesis: LABEL (UNITS) as in distance (cm).

4. All graphs should have a title. A good title that always works is "y" as a function of "x" as in (A). The independent variable is usually plotted on the horizontal (x) axis. "Distance as a Function of Time" is a good title for graph (B).

5. Most graphs should start at the origin (x = 0, y = 0). There are exceptions like graphing temp. If your lowest temp. is 51^o C start at 50^o C. This is because 0^o C has no special meaning (0 cm means no distance, 0^o C doesn't mean no temperature).

6. Pick a logical scale, counting by .1, 1, 2, 5, or 10 etc., not 3, 5, 7, 9, etc.

7. Put a small circle around each data point lightly in pencil. This is necessary due to the uncertainty in the data. Excel will do this for you.

8. Look at your points. Draw the best straight line or smooth curve that goes through as many points as possible. Point to point connections are usually not used in science but are quite valid for plotting irregular data which does NOT display any regularity - like gold prices. Try to miss as many points above the line as you draw as below. Excel will do this for you, as will many graphing programs.

9. If 2 or more lines are plotted on a graph a key is needed. It should be placed on the right side and toward the top if possible. A different color ink must be used for each line. Again Excel will do this for you.

10. If you have a straight line though the origin you have a direct proportion (A). When one variable goes gets larger so does the other. In graph (B) you have an inverse relationship. When one value becomes larger (say pressure) the other (volume) gets smaller.

Here is a quick check list:

TITLE, KEY (if needed), LABELS + UNITS, BIG ENOUGH, LIGHT CIRCLES AROUND POINTS, SMOOTH LINES/CURVES