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BELL RINGER. What is a Bell Ringer?. BELL RINGER. What is a Bell Ringer?. -a question that is answered in the beginning of every class. - these NEED to be written in your notebook EVERY day. BELL RINGER. 9/6 What is a Bell Ringer?
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BELL RINGER What is a Bell Ringer?
BELL RINGER What is a Bell Ringer? -a question that is answered in the beginning of every class - these NEED to be written in your notebook EVERY day
BELL RINGER 9/6 What is a Bell Ringer? A bell ringer is a question that is answered at the beginning of every class. It must done every day at the beginning of class.
BELL RINGER List one thing you learned in school yesterday.
3 Truths and a Lie about me... • I am employed as a beer tester • I am a certified cytogeneticist • I have coached an NBA player • I live in a house with 3 females!
3 Truths and a Lie about me... • I am employed as a beer tester • I am a certified cytogeneticist • I have coached an NBA player • I live in a house with 3 females!
3 Truths and a Lie about me... • I am employed as a beer tester • I am a certified cytogeneticist • I have coached an NBA player • I live in a house with 3 females!
3 Truths and a Lie about me... • I am employed as a beer tester • I am a certified cytogeneticist • I have coached an NBA player • I live in a house with 3 females!
BELL RINGER What is Chemistry?
What is Chemistry?
Chemistry: Two key Questions: • Why do materials behave as they do? • Overall properties and reactivity • How can we take advantage of these properties to something useful? • New materials or improve existing materials • Pharmaceuticals, fuels, foodstuffs…
What is Science? Science is a tool. Medicine: “I have high cholesterol, what should I do?” • Eat Cheerios • Consult your best friend. • Pray to the god Baa and sacrifice a goat. • Take cholesterol lowering medication. • Adjust your diet
Why do you have to take the core classes? Math English History Science
Making Gak PROBLEM: How do you make GAK, efficiently? HYPOTHESIS: = your recipe (amounts of ingredients) EXPERIMENT: = order of mixing, and how it was mixed CONCLUSION: Explain your results
BELL RINGER What is the scientific method?
Gak Lab Finish
Goals The Last Lecture
BELL RINGER What are these?
model test The Scientific Method • Observe an event. • Develop a model (or hypothesis) which makes a prediction. • Test the prediction. • Observe the result. • Make your conclusion • Revise the hypothesis. • Repeat as needed. • A successful hypothesis becomes a ScientificTheory.
Medical Science Patient has high cholesterol Certain chemicals may dissolve cholesterol deposits. Give 100 patients these chemicals, give 100 patients placebo. Same number lower their cholesterol as placebo patients. Try different combo of chemicals. Re-run medical test. Observe results. Lipitor reduces cholesterol.
Everyday Science Engine won’t turn over. Predict battery is dead. Replace battery. Engine now turns over. Not needed. Not needed. Cars won’t work without a fully charged battery.
Everyday Science Try a tomato sauce. Heat pot of tomato sauce. Taste the sauce - bland. Use tomato sauce and garlic! Add garlic, taste - not so bland. The Final Recipe.
Making Gak PROBLEM: How do you make GAK, efficiently? HYPOTHESIS: = your recipe (amounts of ingredients) EXPERIMENT: = order of mixing, and how it was mixed CONCLUSION: Explain your results
BELL RINGER List, in order, the steps of the scientific method.
You have $7.25 in your pocket in quarters. How many quarters do you have? 1 dollar 7.25 dollars 4 quarters X = 1 = 29 quarters
A rattlesnake is 2.44 m long. How long is the snake in cm? a) 2440 cm b) 244 cm c) 24.4 cm
Chemistry In Action On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mar’s atmosphere 100 km lower than planned and was destroyed by heat. 1 lb = 1 N 1 lb = 4.45 N “This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses till the end of time.”
BELL RINGER • Perform the following conversions - • 1.76 kg = ____________ dg • 0.0036 mm = _________ m • 5.2 x 10-2L = _________ cL
Observation: Inference Lab
Counting Significant Figures RULE 1. All non-zero digits in a measured number are significant. Only a zero could indicate that rounding occurred. Number of Significant Figures 38.15 cm 4 5.6 ft 2 65.6 lb ___ 122.55 m___
Zeros in Front RULE 2. Leading zeros in decimal numbers are NOT significant. Number of Significant Figures 0.008 mm 1 0.0156 oz 3 0.0042 lb ____ 0.000262 mL ____
Sandwiched Zeros RULE 3. Zeros between nonzero numbers are significant. (They can not be rounded unless they are on an end of a number.) Number of Significant Figures 50.8 mm 3 2001 min 4 0.702 lb ____ 0.00405 m ____
Trailing Zeros RULE 4. Trailing zeros in numbers without decimals are NOT significant. They are only serving as place holders. Number of Significant Figures 25,000 in 2 200. yr 3 48,600 gal ____ 25,005,000 g ____
BELL RINGER What are the volumes in the cylinders on the right? Remember Sig Fig’s A B C
Significant Figures • The numbers reported in a measurement are limited by the measuring tool • Significant figures in a measurement include the known digits plus one estimated digit
Significant Numbers in Calculations • A calculated answer cannot be more precise than the measuring tool. • A calculated answer must be rounded to match the least precise measurement.
Adding and Subtracting Only concerned with numbers AFTER the decimal point. Round to the least precise measurement. 25.2one decimal place + 1.34two decimal places 26.54 answer 26.5one decimal place
Learning Check In each calculation, round the answer to the correct number of significant figures. A. 235.05 + 19.6 + 2.1 = 1) 256.75 2) 256.8 3) 257 B. 58.925 - 18.2 = 1) 40.725 2) 40.73 3) 40.7
Multiplying and Dividing Round (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.
Learning Check A. 2.19 X 4.2 = 1) 9 2) 9.2 3) 9.198 B. 4.311 ÷ 0.07 = 1)61.582) 62 3) 60 C. 2.54 X 0.0028 = 0.0105 X 0.060 1) 11.3 2) 11 3) 0.041
Theory: A Unifying Principle that explains Facts and Laws • Theories are not hypothesis • Continuously revised as new data obtained • Theory of Evolution Scientific Laws and Theories • Law: Repeatedly tested hypothesis that has not been contradicted • Law of Gravity