snail races snail races using the scientific method and the metric system
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Snail Races Snail Races
Using the Scientific Method Using the Scientific Method and the Metric Systemand the Metric System
How Do Biologists Study Living Things?How Do Biologists Study Living Things? Scientific MethodScientific Method
•Observation: Observation: objective notation of a phenomenonobjective notation of a phenomenon
•Hypothesis: Hypothesis: question that can be tested by question that can be tested by experimentationexperimentation
– ExperimentExperiment– Data CollectionData Collection– ConclusionConclusion
•Supported HypothesisSupported Hypothesis•Theory: Theory: hypothesis supported by repeated testing hypothesis supported by repeated testing
•Principle: Principle: theory supported over a long period of timetheory supported over a long period of time
TodayToday
• ObservationObservation– Behavior of snail Behavior of snail – Anatomical description using microscopeAnatomical description using microscope
• HypothesisHypothesis– Are large or small snails faster?Are large or small snails faster?– Are warm or cold snails faster? Are warm or cold snails faster?
Put your snail here(clean off later!)
Adjust to focus
Use BOTH eyes
Set at 1X to startUse to increase image size
Turn light on
Observations with a Dissecting Microscope
Metric SystemMetric System
LengthLength WeightWeight VolumeVolumeMeter (m)Meter (m) Gram (g)Gram (g) Liter (l)Liter (l)
Centimeter (cm) Centimeter (cm)
100 cm = 1 m100 cm = 1 m
Millimeter (mm)Millimeter (mm)1000 mm = 1 m1000 mm = 1 m
10 mm = 1 cm10 mm = 1 cm
MilligramMilligram1000 mg = 1 g1000 mg = 1 g
Milliliter (ml)Milliliter (ml)
1000 ml = 1 liter1000 ml = 1 liter
A scientific measurement system where A scientific measurement system where quantities differ by factors of 10.quantities differ by factors of 10.
Metric Measurements in Today’s LabMetric Measurements in Today’s Lab
LengthLength WeightWeight VolumeVolumeRulerRuler ScaleScale Graduated Graduated
cylinder using cylinder using water water displacementdisplacement
Grams and tenths Grams and tenths of a gramof a gram
Ex. 8.6 gramsEx. 8.6 grams
Centimeter (cm) Centimeter (cm) and tenths of cmand tenths of cm
Ex. 5.3 cmEx. 5.3 cm
Milliliter (ml)Milliliter (ml)
Ex. 11 mlEx. 11 ml
Length MeasurementsLength Measurements
LengthLengthRulerRuler
Centimeter (cm) Centimeter (cm) and tenths of cmand tenths of cm
Ex. 5.3 cmEx. 5.3 cm
Weight MeasurementsWeight Measurements
WeightWeight
ScaleScale
Grams and tenths Grams and tenths of a gramof a gram
Ex. 8.6 gramsEx. 8.6 grams
Volume MeasurementsVolume Measurements
VolumeVolumeGraduated cylinder Graduated cylinder using water using water displacementdisplacement
Milliliter (ml)Milliliter (ml)
Ex. 11 mlEx. 11 ml
Hint: Measure your snail’s volume after the Hint: Measure your snail’s volume after the races to keep him/her moving at optimal speed!races to keep him/her moving at optimal speed!
MathematicsMathematics
• Average = Average = sum of distancessum of distances
number of measurementsnumber of measurements
• Significant figuresSignificant figures– Consistent with the smallest unit on the Consistent with the smallest unit on the
measuring devicemeasuring device– Eg. 2.43 cm, should be reported as 2.4 cmEg. 2.43 cm, should be reported as 2.4 cm– Round up if next number is 5 or aboveRound up if next number is 5 or above
GraphingGraphing
0
1
2
3
4
5
6
Small Medium Large
Warm
Cold
Ave
rage
Spe
ed (
cm/m
in)
Snail Size
Worksheet Worksheet
• Complete pages 7-13 from lab Complete pages 7-13 from lab manualmanual
• Be sure your instructor checks your Be sure your instructor checks your completed worksheet before you completed worksheet before you leave the lableave the lab
CLEAN UP!CLEAN UP!
Make sure your lab station and the Make sure your lab station and the surrounding benches look the same way surrounding benches look the same way
they did when you arrived!they did when you arrived!
CLEAN UP!CLEAN UP!
• Return your snail to the aquariumReturn your snail to the aquarium• Empty and rinse graduated cylindersEmpty and rinse graduated cylinders• Rinse and dry watch glassesRinse and dry watch glasses• Leave glassware, rulers, string in a neat Leave glassware, rulers, string in a neat
arrangement at your stationarrangement at your station• Clean your work areaClean your work area• Clean microscope stage, cover and Clean microscope stage, cover and
return microscope to cabinetreturn microscope to cabinet