SI Units International System of Units (SI)

Metric Preferences

Graduated Cylinder Measure 26.1mL

Scale Weigh the object

Ruler Measure the length of the object Side of book

Bubble Lab Does sugar or salt affect the ability to blow bubbles?

What are the steps of the scientific method? Problem The problem is the question we want to answer Must be specific and testable Observations Objective (using facts), not subjective (using opinions) Quantitative (counting or measuring) and qualitative Hypothesis A hypothesis is an educated prediction based on observations. MUST BE TESTABLE. 9

Experiment An experiment tests the hypothesis Controlled variables—factors that are kept constant Ex. Manipulated variable—factor that changes (only have one of these at a time) Independent variable—factor that causes a change Dependent variable—factor that changes (the thing you’re measuring). Controlled variable: amount of sunlight, pot size, type of soil Manipulated variable: amount of water Independent variable: amount of water Dependent variable: plant height 10

Data analysis Conclusion Data analysis is making judgments or evaluations about the results of an experiment Use graphs, tables, and statistics Conclusion A conclusion explains the results of the experiment Tell whether or not the hypothesis was supported Explain sources of error 11

Retest (OR revise hypothesis) Experiment is redone many times Theory A theory is a conclusion that is accepted by many scientists that EXPLAINS something. Law A law describes behavior of natural events 12

PROBLEM OBSERVATIONS HYPOTHESIS EXPERIMENT ANALYZE DATA DRAW CONCLUSIONS RETEST DISCARD THEORY 13

Accuracy vs. Precision Accuracy: How close to the real value Precision: How close a series of measurements are to each other

Scientific Notation Method of writing very small or very large numbers A positive exponent means the decimal moved to the left. A negative exponent means the decimal moved to the right

Scientific Notation 602,200,000,000,000,000,000,000 = ? Step 1: Make the Coefficient less than 10 and more than 1. Step 2: Find out how many places over the decimal has to move to give you the number in step 1.

Scientific Notation 5,300,000 = ? 4,302,000,000 = ? -24,500 = ? .000034 = ? -.0000007 = ?

Scientific Notation 5.3 x 104 = ? 7.02 x 108 = ? -3.21 x 103 = ?

Scientific Notation Addition and Subtraction: Make the exponents the same number Add/Subtract the coefficient 5.3x102 + 2.6x103 = 5.3x102 + 26.x102 = 31.3x102= 3.13x103

Scientific Notation Multiplication and Division Add or Subtract exponents Multiply or Divide coefficients Multiply Divide 5.2x102 x 4.8x104 = 5.0x104 ÷ 2.5x103= (5.2 x 4.8) x10(2 + 4) (5.0 ÷ 2.5) x10(4-3)= 24.96x106 2.0x101 2.496x107

Scientific Notation 5.6x104 + 4.3x102 = ? 4.0x106 – 8.3x105 = ?

Significant Figures Rounding Numbers: -Round up if the digit to the right is between 5-9 59.48  59.5 -Don’t change the number if the digit is between 0-4 3.84  3.8 Significant Figures Tell You What Number To Round To!

Significant Figures All Non-zero numbers (1,2,3,4,5,6,7,8,9) are significant Zeros – Front of number are NEVER significant 0.0071, 0.42, .000099 all have 2 sig. figs Middle of number are ALWAYS significant 7003, 40.79, 1.503 all have 4 sig. figs End are SOMETIMES significant At end AFTER decimal, ALWAYS significant 36.00, 1.010, 9.000 all have 4 sig figs At end BEFORE decimal, NEVER significant 300, 7000, 20000 all have 1 sig fig

Significant Figures 5.30 = ? 76009.0 = ? 1900 = ? .0000000891 = ?

Significant Figures Addition and Subtraction Match the number with the least number of decimals Ex: 13.21 + 4.1 = 17.3 13.21 + 4.100 = 17.31 13.21 + 4 = 17 Multiplication and Division Match value with fewest number of sig figs Ex: 2.00 x 11 =22 2.00 x 11.0 = 22.0 2 x 11 = 20

1000 k BIG 100 h 10 dk 1 .1 d .01 c .001 m SMALL BASE (m, g, L) 27 kilo BIG 100 h hecto 10 dk deca 1 BASE (m, g, L) .1 d deci .01 c centi .001 m milli SMALL 27

How do you convert between metric units? Determine whether you are going up the ladder or down the ladder. If you go up, move the decimal to the left. If you go down, move the decimal to the right. Use the ladder to determine how many places to move the decimal. The number of steps on the ladder is equal to the number of decimal places. Write the correct units with your answer. 28

Conversions How many quarters make up $2? How many dimes make up $3? How many inches make up 2ft?

Conversions Convert 892cm to meters…… Make the units cancel to get the units you want Find the conversion factor Which is bigger? (This will have the value of 1) Which one is smaller (This will have the big number) What is the difference between them (Count how many steps you take, each one is 101 more)

Conversions 23mL = _____ L 45km = _____ cm 78.1cm = ______ mm 750dg = _____ mg .073m = ______ mm

Conversions 8.9g/cm3 = _______ kg/m3 4.23m/L = _______ cm/mL 19.6cm/L = ______ m/mL 2.5g/m3 = ______ g/cm3