View
220
Download
0
Category
Tags:
Preview:
Citation preview
What is Science?
• Science--organized way of using evidence to learn about the natural world
• Goals:– Investigate and
understand natural world to explain events.
– Use explanations to make useful predictions
Chemistry and Physics
• Chemistry- the branch of science that deals with the identification of the substances of which matter is composed
• Physics- the branch of science concerned with the nature and properties of matter and energy
Scientific Method
• An organized way of solving problems– 1.Observations and
questions– 2.Hypothesis– 3.Experimental procedure– 4.Record results– 5.Draw conclusions
#1 Observations/Questions
• 1.Observations/Questions – What you see– Inferences are your logical
interpretations of what you see.– Questions then arise…….– Why should I care?
• Observe that people on average are losing their hearing at an earlier age .
60,000 individuals under the age of 18 in the U.S. have severe hearing loss
#2 Hypothesis
• 2.Hypothesis-scientific and testable explanation for observations– “If……then……”– If people turn up their
headphones too loudly, then they will suffer hearing loss in time
#3 Procedure• 3.Experimental procedure- designed to test
hypothesis • Split subjects you are testing into groups:
#1 Experimental Group-given the experimental factor or changed in some way
#2 Control Group:-NOT changed
Experimental group with Experimental group with music turned up to high music turned up to high
volumevolume
Control GroupControl GroupMusic turned up just above Music turned up just above
hearing levelhearing level
#3 Procedure
• Variable-factor in experiment that is subject to change.– Independent variable- factor in experiment that’s
purposely changed and is independent of anything else—music volume
– Dependent variable —factor that a scientist observes for responses in because it depends on what the scientist did earlier—loss of hearing, sensitivity to sound, ringing in ears, etc.
– Only test ONE independent variable while having MANY constants.
#3 Procedure
• Must be a controlled, reproducible procedure
Testing effects of Testing effects of only ONE independentonly ONE independentvariable all the rest are variable all the rest are CONSTANT!!!!!CONSTANT!!!!!
Other scientists Other scientists need to be able to need to be able to reproduce it and reproduce it and find same results.find same results.
#3 ProcedureEXPERIMENT
EXPERIMENTAL GROUP
Check the resultsin time
CONTROL GROUP
Difference is the independent variable
Compare the dependent variable
Check the resultsin time
#4 Results
• 4. Results– Record data – Qualitative data -physical traits
(qualities) that can be described– Quantitative data -measurements
(quantities) that can be taken– Pictures, tables, graphs– Trends noticed
#4 Results
Qualitative? Quantitative?
Experimental group: Control group: music turned up to music turned up just high volume above hearing level
#4 Results
• When you graph data:– Independent
variable goes on the x-axis (volume)
– The dependent variable goes on the y-axis (hearing sensitivity level)
x-axis volumey-a
xis h
earin
g se
nsitiv
ity le
vel
Must be even increments
#4 Results
• Precision vs. Accuracy– Precision- describes
how closely measurements are to one another
– Accuracy- compares a measurement to a real or accepted standard
#5 Conclusions
• 5.Conclusions– Hypothesis is either supported or
rejected. NEVER “PROVEN!”– If supported further testing – If rejected hypothesis changed and
tested again– Can be partly true– Findings always useful!!!
• Conclusion?
Hypothesis supported: loud music is one of the most common causes of hearing loss
Overview
State the Question or Problem
Form a Hypothesis
Set Up a Controlled Experiment
Record Results
Draw a Conclusion
Publish Results
Scientific Theories• Theory-a well-supported explanation of some
aspect of the natural world– ***It’s the closest you can get to scientific fact;
not a guess – It’s a hypothesis than has been tested and
supported many times– Used to make future predictions– If contradictory evidence found, theory revised or
replaced– There is no evidence against them
• A hypothesis is a POSSIBLE explanation, whereas a theory IS an explanation
Scientists’ Tools
• Common measurement system– Metric system or (SI)- a
measurement system used worldwide by scientists based on multiples of 10•Mass-grams (g)•Volume-liters (L)•Distance-meters (m)•Temperature- Kelvin (K) or
Celsius (OC)
Temperature• Fahrenheit scale- water
freezes at 32oF and boils at 212oF
• Celsius scale- 0oC is the freezing point of water and 100oC is the boiling point
F = (9)C + 32 5 • “30 is hot. 20 is nice. 10 put a coat on, 0 is ice.”
Temperature
• Kelvin is the actual metric scale for temp where 0 K is absolute zero and the coldest possible temperature equal to -273oC
K = 273 + oCWater freezes at 0oC
which is = 273K
Volume and Density
• Volume= length X width X height• Density= mass (g) volume (L)• Density video
Which is more dense?
Kilo Hecto
Deka
UNITS
Gram
Liter
Meter
UNITS
deci centi
milli
Metric to Metric Map
“Use it and you will never get lost!”
How To Use Your Map
1) Start at the unit/prefix given to you (starting point).2) Count the number of steps/places to the unit/prefix you want
(final destination)each is a factor of 10.3) Move the decimal point the number of steps/places in the
same direction.
SMALLESTLARGEST
Kilo Hecto
Deka Gram deci centi
milli
Check for Understanding
How many mg are in 3.6 Kg?
Starting point Final Destination
3,600,000 mg6 places to the right of the decimal point
Kilo Hecto
Deka Meter deci centi
milli
Check for Understanding
How many hm are in 12.67 mm?
Starting pointFinal Destination
0.0001267 hm5 places to the left of the decimal point
Helpful Mnemonic
Try to create your own mnemonic to help you remember the prefixes and their order. This will be important because you will not receive the
metric map on your quiz.
Kings Have Diamonds
BUT Diamonds
Cost Money
Scientific Notation• Sometimes numbers are too big or too small
to write with ease and clarity– The Andromeda Galaxy (the closest one to our
Milky Way galaxy) contains at least 200,000,000,000 stars.
– The weight of an alpha particle, which is emitted in the radioactive decay of Plutonium-239, is0.000,000,000,000,000,000,000,000,006,645 kilograms.
• Scientific notation is used to express these large or small numbers in a convenient way
• Remember that:– 100 = 10 X 10 = 102
– 1000 = 10 X 10 X 10 = 103
– 10,000 = 10 X 10 X 10 X 10 = 104
ExampleWrite 4,776 in scientific notation
Place the decimal immediately to the right of the left-most non-zero number. This should give you a number between
one and ten.
4.776Count the number of digits between the old and the new
decimal point, this gives the power, n of 10 (10n).
4 776 X 103
Since the decimal is shifted to the left, the exponent is positive.
4.776 x 103
3 Digits
Check for Understanding
Write 0.0246 in scientific notation Place the decimal immediately to the right of the left-most non-zero number. This should give you a number between
one and ten
2.46Count the number of digits between the old and the new
decimal point, this gives the power, n of 10 (10n).
X 10-2
Since the decimal is shifted to the right, the exponent is negative.
2.46 x 10-2
2 Digits
0 02 46
Check for Understanding
Write 4.953 x 104 in standard form Write the decimal number.
4.953Move the decimal the number of places specified by the powers of ten: to the right since it is positive.
X 104 4 9530Rewrite the number in integer/standard form.
49,530
4 Places
Write 8.397 x 10-1 in standard form
Write the decimal number.
8.397Move the decimal the number of places specified by
the powers of ten: to the left since it is negative.
X 10-1 0 8 397Rewrite the number in integer/standard form.
0.8397
1 Place
Multiplying and Dividing With Your Calculator
1. Punch the number (the digit number) into your calculator.
2. Push the EE or EXP button. Do NOT use the x (times) button!!
3. Enter the exponent number. Use the +/- button to change its sign.
4. Voila! Treat this number normally in all subsequent calculations.
Check for Understanding
• You can use scientific notation to complete calculations without a calculator for ridiculously huge numbers
• Example• Multiply 2,500,000,000,000,000 times
4,000,000,000Answer?
Check for Understanding
• You can use scientific notation to complete calculations without a calculator for ridiculously huge numbers
• Example• Multiply 2,500,000,000,000,000 times
4,000,000,000Answer? 1 X 1025
1. Read the question. The question will provide you with information that identifies your starting point and your final destination.
• Starting point = the number and unit provided by the question
• Final destination = the units desired after converting
2. Write your starting point and your final destination.3. Determine how you will get from your starting point to
your final destination (simply find “connections” or conversion factors between your starting and final unit).
Metric to US Conversion Steps(Dimensional Analysis)
Metric to US Conversion Steps(Dimensional Analysis)
4. Create a fraction with your starting point.5. Write in the bottom unit of the new fraction. This should be the same as the top unit of the previous fraction.6. Write one set of “connections” or conversion factors into the fraction. Your bottom unit will guide you.7. Ask yourself, “Do I have the desired unit (final destination) on the top of the new fraction?”
NO YES
8. Cancel any units that are diagonal. (This should leave you with only the units that represent your final destination)9. Multiply the top of the fractions…multiply the bottom of the fractions…divide the top by the bottom.
(Go back to step 5) (Proceed to step 8)
Practice Conversions
1. How many seconds are in 6 minutes?
2. How many centimeters are in 27 inches?
3. If a truck weighs 15,356 pounds, how many tons is it?
4. If you had 10.5 gallons of milk, how many pints would you have?
5. Students go to school for 180 days. How many minutes is this equal to?
How many seconds are in 6 minutes?
6 minutes seconds
(6 minutes)1
( )( )
secondsminute
360 seconds
601
=(6)(60 seconds)
(1)(1)
=
Step 1 – Read the question and determine
what information it provides you with (starting point & final destination)
Step 2 – Write down your starting point and your final
destination1 minute = 60 secondsStep 3 –
Determine how you will
getfrom your
starting point to your final destination
(list any “connections” or conversion
factors) Step 4 – Create a fraction with your starting point
Step 5 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 6 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is YES, so
we move on to step 9
Step 8 – Cancel all diagonal units. Once this is done,
your final destination should be the only unit left – in this
case seconds
Step 9 – Multiply the top of the fractions; multiply the bottom of the fractions;
divide the product of the top by the product of the bottom
Starting Point
Final Destination
How many centimeters are in 27 inches?
27 inches centimeters
(27 inches)1
( )( )
cminch
68.58 centimeters
2.541
= (27)(2.54 cm)(1)(1)
=
Step 1 – Read the question and determine
what information it provides you with (starting point & final destination)
Step 2 – Write down your starting point and your final
destination1 inch = 2.54 centimetersStep 3 – Determine
how you will get
from your starting
point to your final
destination (list any
“connections” or
conversion factors)
Step 4 – Create a fraction by placing your starting
point over one
Step 5 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 6 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is YES, so
we move on to step 9
Step 8 – Cancel all diagonal units. Once this is done,
your final destination should be the only unit left – in this
case centimeters
Step 9 – Multiply the top of the fractions; multiply the bottom of the fractions;
divide the product of the top by the product of the bottom
Starting Point
Final Destination
If a truck weighs 15,356 pounds, how many tons is it?
15,356 pounds tons
(15,356 lbs.)1
( )( )
tonlbs.
7.678 tons
12000
=(15,356)(1 ton)
(1)(2000)
=
Step 1 – Read the question and determine
what information it provides you with (starting point & final destination)
Step 2 – Write down your starting point and your final
destination2000 pounds = 1 tonStep 3 – Determine
how you will get
from your starting point to your final destination
(list any “connections” or conversion
factors) Step 4 – Create a fraction by placing your starting
point over one
Step 5 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 6 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is YES, so
we move on to step 9
Step 8 – Cancel all diagonal units. Once this is done,
your final destination should be the only unit left – in this
case tonsStep 9 – Multiply the top of the fractions; multiply the bottom of the fractions;
divide the product of the top by the product of the bottom
Starting Point
Final Destination
If you had 10.5 gallons of milk, how many pints would you have?
10.5 gallons pints
(10.5 gallons)1
( )( )
quartsgallon
84 pints
41
=(10.5)(4)(2 pints)
(1)(1)(1) =
Step 1 – Read the question and determine
what information it provides you with (starting point & final destination)
Step 2 – Write down your starting point and your final
destination
1 gallon = 4 quarts1 quart = 2 pintsStep 3 –
Determine how you will
getfrom your
starting point to your final destination
(list any “connections” or conversion
factors) Step 4 – Create a fraction by placing your starting
point over one
Step 5 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 6 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is NO, so we
move back to step 5
Step 9 – Cancel all diagonal units. Once this is done,
your final destination should be the only unit left – in this
case pints
Step 10 – Multiply the top of the fractions; multiply the bottom of the fractions;
divide the product of the top by the product of the
bottom
Starting Point
Final Destination
( )( )
pintsquart
21
Step 6 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 8 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is YES, so
we move on to step 9
Students go to school for 180 days. How many minutes is this equal to?
180 days minutes
(180 days)1
( )( )
hoursday
259,200 minutes
241
=(180)(24)(60 minutes)
(1)(1)(1) =
Step 1 – Read the question and determine
what information it provides you with (starting point & final destination)
Step 2 – Write down your starting point and your final
destination
1 day = 24 hours1 hour = 60 minutesStep 3 –
Determine how you will
getfrom your
starting point to your final destination
(list any “connections” or conversion
factors) Step 4 – Create a fraction by placing your starting
point over one
Step 6 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 7 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 8 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is NO, so we
move back to step 5
Step 9 – Cancel all diagonal units. Once this is done, your final destination should be the
only unit left – in this case minutes
Step 9 – Multiply the top of the fractions; multiply
the bottom of the fractions; divide the
product of the top by the product of the bottom
Starting Point
Final Destination
( )( )
minuteshour
601
Step 6 – Write in the bottom unit of the new fraction (this is the same as the top unit of
your previous fraction)
Step 8 – Write the appropriate conversion
factor into the fraction. Your bottom unit will guide you.
Step 7 – Determine if this top unit is the desired unit (your
final destination). In this case the answer is YES, so
we move on to step 9
Recommended