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. WeightMass

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 MethodKilo - k1000 units Hecto -

h100units

Deka - da 10

unitsBasic Unit (g, m,

L)Deci - d

0.1units Centi - c

0.01units

Milli - m0.001units

To convert to a larger unit, move decimal point to the left or divide.

To convert to a smaller unit, move decimal point to the right or multiply.

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 hr60 min› ____ 1 hr

Step 3: Cross out, or cancel, the units that

appear the same on both top and bottom:› 50 hr60 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 hr60 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 hr60 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