Snail Races Snail Races Using the Scientific Method and the Metric System

How Do Biologists Study Living Things? Scientific Method Observation: objective notation of a phenomenonObservation: objective notation of a phenomenon Hypothesis: question that can be tested by experimentationHypothesis: question that can be tested by experimentation –Experiment –Data Collection –Conclusion Supported HypothesisSupported Hypothesis Theory: hypothesis supported by repeated testingTheory: hypothesis supported by repeated testing Principle: theory supported over a long period of timePrinciple: theory supported over a long period of time

Today ObservationObservation –Behavior of snail –Anatomical description using microscope HypothesisHypothesis –Are large or small 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 start Use to increase image size Turn light on Observations with a Dissecting Microscope

Metric System LengthWeightVolume Meter (m) Gram (g) Liter (l) Centimeter (cm) 100 cm = 1 m Millimeter (mm) 1000 mm = 1 m 10 mm = 1 cm Milligram 1000 mg = 1 g Milliliter (ml) 1000 ml = 1 liter A scientific measurement system where quantities differ by factors of 10.

Metric Measurements in Today’s Lab LengthWeightVolume RulerScale Graduated cylinder using water displacement Grams and tenths of a gram Ex. 8.6 grams Centimeter (cm) and tenths of cm Ex. 5.3 cm Milliliter (ml) Ex. 11 ml

Length Measurements Length Ruler Centimeter (cm) and tenths of cm Ex. 5.3 cm

Weight Measurements WeightScale Grams and tenths of a gram Ex. 8.6 grams

Volume Measurements Volume Graduated cylinder using water displacement Milliliter (ml) Ex. 11 ml Hint: Measure your snail’s volume after the races to keep him/her moving at optimal speed!

Mathematics Average = sum of distancesAverage = sum of distances number of measurements number of measurements Significant figuresSignificant figures –Consistent with the smallest unit on the measuring device –Eg cm, should be reported as 2.4 cm –Round up if next number is 5 or above

Graphing Average Speed (cm/min) Snail Size

Worksheet Complete pages 7-13 from lab manualComplete pages 7-13 from lab manual Be sure your instructor checks your completed worksheet before you leave the labBe sure your instructor checks your completed worksheet before you leave the lab

CLEAN UP! Make sure your lab station and the surrounding benches look the same way they did when you arrived!

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 arrangement at your stationLeave glassware, rulers, string in a neat arrangement at your station Clean your work areaClean your work area Clean microscope stage, cover and return microscope to cabinetClean microscope stage, cover and return microscope to cabinet