The Scientific Method

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?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 music turned up to high volume Control Group Music turned up just above hearing 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 only ONE independent variable all the rest are CONSTANT!!!!! Other scientists need to be able to reproduce it and find same results.

#3 Procedure EXPERIMENT EXPERIMENTAL GROUP Check the results in time CONTROL GROUP Difference is the independent variable Compare the dependent variable Check the results in 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 volume y-axis hearing sensitivity level 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

Ethics When experiments are not possible –Animals in natural habitat –Ethical concerns

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 ( O C)

Temperature Fahrenheit scale- water freezes at 32 o F and boils at 212 o F Celsius scale- 0 o C is the freezing point of water and 100 o C is the boiling point F = (9)C “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 -273 o C K = o C Water freezes at 0 o C which is = 273K

Volume and Density Volume= length X width X height Density= mass (g) volume (L) Density video Which is more dense?

KiloHectoDeka UNITS Gram Liter Meter UNITS decicentimilli 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. SMALLEST LARGEST

KiloHectoDeka Gram decicentimilli Check for Understanding How many mg are in 3.6 Kg? Starting pointFinal Destination 3,600,000 mg 6 places to the right of the decimal point

KiloHectoDeka Meter decicentimilli Check for Understanding How many hm are in mm? Starting pointFinal Destination hm 5 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. KingsHaveDiamonds BUT DiamondsCostMoney

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, is 0.000,000,000,000,000,000,000,000,006,645 kilograms. Scientific notation is used to express these large or small numbers in a convenient way Remember that: – 100 = 10 X 10 = 10 2 –1000 = 10 X 10 X 10 = 10 3 –10,000 = 10 X 10 X 10 X 10 = 10 4

Example Write 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 Count the number of digits between the old and the new decimal point, this gives the power, n of 10 (10 n ) X 10 3 Since the decimal is shifted to the left, the exponent is positive x Digits

Check for Understanding Write 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 2.46 Count the number of digits between the old and the new decimal point, this gives the power, n of 10 (10 n ). X Since the decimal is shifted to the right, the exponent is negative x Digits

Check for Understanding Write x 10 4 in standard form Write the decimal number Move the decimal the number of places specified by the powers of ten: to the right since it is positive. X Rewrite the number in integer/standard form. 49,530 4 Places

Write x in standard form Write the decimal number Move the decimal the number of places specified by the powers of ten: to the left since it is negative. X Rewrite the number in integer/standard form 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 4,000,000,000 Answer?

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 4,000,000,000 Answer? 1 X 10 25

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)

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?” NOYES 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 ( ) seconds minute 360 seconds 60 1 = (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 destination 1 minute = 60 seconds Step 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 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 ( ) cm inch centimeters = (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 destination 1 inch = 2.54 centimeters Step 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 ( ) ton lbs tons = (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 destination 2000 pounds = 1 ton Step 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 tons 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 you had 10.5 gallons of milk, how many pints would you have? 10.5 gallons  pints (10.5 gallons) 1 ( ) quarts gallon 84 pints 4 1 = (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 quarts 1 quart = 2 pints Step 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 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 PointFinal Destination ( ) pints quart 2 1 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 ( ) hours day 259,200 minutes 24 1 = (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 hours 1 hour = 60 minutes Step 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 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 PointFinal Destination ( ) minutes hour 60 1 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