Warm Up-September 7th Flower Power SpongeBob loves to garden and wants to grow lots of pink flowers for his pal Sandy. He bought a special Flower Power fertilizer to see if it will help plants produce more flowers. He plants two plants of the same size in separate containers with the same amount of potting soil. He places one plant in a sunny window and waters it every day with fertilized water. He places the other plant on a shelf in a closet and waters it with plain water every other day. What did SpongeBob do wrong in this experiment? Explain. What should SpongeBob do to test the effectiveness of Flower Power fertilizer?
Warm Up – 8/21 Stacy decided to do an experiment to test which brand of artificial sugar tasted the most like real sugar. In the experiment she tested three different brands Splenda, Equal and Stevia. Name the independent variable, dependent variable and at least 3 controls in Stacy’s experiment.
The Metric System… Class Notes
The Metric System Is • The standard system used around the world by scientists. • We refer to it as the International System of Units or SI. • It is based on a system of decimals. • It is used to measure length, mass, volume, density and temperature.
Common Metric Units • Kilo = 1000 Super Sized • Hecta = 100 Bigger • Deka = 10 Big • Base Unit – Meter – Liter – Gram • Deci = 0.1 Small • Centi = 0.01 Smaller • Milli = 0.001 Smallest • Remember:King Henry Died By Drinking Chocolate Milk
Mass vs. Weight Mass • The amount of matter in an object • Tool: triple beam balance • Unit: gram • Constant no matter where the object is located Weight • The amount of gravitational pull on an object • Tool: spring scale • Unit: newton • Varies depending on location
Mass and Weight: Similarities • As the mass rises so does weight • We use both to describe the heaviness of an object • On earth these go up and down together
Theory vs. Law • Theory • An explanation for many hypothesis and observations • Explains an observation and helps predict what may happen in the future • May change as new observations arise • Law • A summary of many experimental results • Tells you how things work • Tells you what will happen
Length • The distance from one point on an object to another • Measured in Meters • The smallest unit of length is the millimeter (mm). When would you use millimeters to measure length? • 125 mm = ___ cm • Largest unit of length is Kilometer, what would you measure using the km?
Mass • Measured in grams • Mass measures the amount of matter in an object (BUT NOT THE WEIGHT!) • Measured using a triple beam balance
Weight • The measure of gravitational pull on an object. • Measured in newton's using a spring scale.
Volume • Measured in Liters • Volume is the amount of space an object takes up • 1 mL = 1cm3
Density • The amount of mass in a given volume. • Density = mass/volume • g/mL • Which is more dense?
Temperature • Measured in Celsius • Water freezes at 0˚C and boils at 100˚C
Inertia • An objects resistance to change in motion • A change in motion could be moving something or slowing something down • Inertia is directly related to mass…the more massive something is the harder it will be to change its motion.
Would it be easier to… • Stop a football player or toddler running down the field • Move a cargo ship or a sailboat • Lift a full dresser or empty it out and then lift it • Slow down a single engine plane or a commercial airliner • It is harder to stop or move things that have greater mass or more inertia!
Warm Up – 9/9 Which SI unit would you probably use to express the height of your desk? What would be the appropriate tool to use when measuring the mass of a spoon? Ms. Gould is measuring small amounts of liquid chemicals out to be used in an experiment. Name the tool and SI unit that she is most likely using.
Metric Conversions • Since the metric system is a decimal system, it is easy to convert between units. • There are several methods to use: • The stair step method • Decimal Hopping • Factor Label Method
The Stair Step Method Kilo - k 1000 units To convert to a smaller unit, move decimal point to the right or multiply. Hecto - h 100 units Deka - da 10 units Basic Unit (g, m, L) Deci - d 0.1 units To convert to a larger unit, move decimal point to the left or divide. Centi - c 0.01 units Milli - m 0.001 units 1.) 1000 mg = 1 g 3.) 109 g = ____ kg 2.) 160 cm = 1600 mm 4.)14 km = ____ m
Decimal Hopping Once you master the stairs, decimal hopping should become easier. Since the metric system is set up by powers of ten all we have to do is move the decimal point to change units. If you are moving to a LARGER unit move the decimal to the LEFT. If you are moving to a SMALLER unit move the decimal to the RIGHT.
Example: smaller to larger Moving to a larger unit… 33 m = ____ km 1st place your decimal point 33. m = ____ km 2nd, how many places away is km from m? Larger moves LEFT. 33. m = ____ km 33. m = .033 km
Example: larger to smaller Moving to a smaller unit… 67.2 dm = ____ mm 1st the decimal is placed, we will start hopping from that point 67.2 dm = ____ mm 2nd , how many places is dm from mm? 67.2 dm = ____ mm 67.2 dm = 6720 mm
Try Some… • 460 L = ____ mL • 90 cg = ____ kg • 23.56 km = ____ hm • 460 L = 460,000 mL • 90 cg = .0009 kg • 23.56 km = 235.6 hm
Another Method for Conversion…Factor Label • Sometimes it is not as easy as moving the decimal. • For instance when converting from pounds to kilograms we cannot just move the decimal • for these conversion we use the factor label method.
Step 1: Example: how many seconds are in 50 hours? Put the known quantity in the upper-left space: 50 hr
Step 2: • Put the conversion factor in the next set of boxes to the right. Make sure that units match diagonally: • 50 hr 60 min • ____ 1 hr
Step 3: • Cross out, or cancel, the units that appear the same on both top and bottom: • 50 hr 60 min • ____ 1 hr
Step 4: • Now ask, “is the unit that’s not crossed out the one that I want?” • If the answer is “yes,” then continue to step 5 • If the answer is “no;” return to step 2 • 50 hr 60 min 60 sec • ____ 1 hr 1 min
Step 5: • To solve the problem, multiply the numbers on the top row. • 50 x 60 x 60 = 180,000 • Then multiply the numbers on the bottom row • 1 x 1 x 1 • 50 hr 60 min 60 sec • ____ 1 hr 1 min
Step 5 (cont.): • Now, divide the top row’s product by the bottom row’s product • 180,000 / 1 = 180,000 seconds
Ticket Out the Door • Use the factor label method to determine how many inches are in 20 miles. • 12 in = 1 foot • 3 feet = 1 yard • 5, 280 feet = 1 mile