How to Science [Part 5: Mathematics]

Welch Labs
Jan 29, 2018
10 notes
10 Notes in this Video

Rejecting Direct Proportionality: When Initial Hypotheses Fail

HypothesisRejection DirectProportionality ScientificFailure DataDrivenRefinement
00:38

The reasonable initial guess—that tension and frequency are directly proportional—is quickly rejected when data shows doubling tension (1000g to 2000g) only increases frequency by factor 1.4, not 2.

Square Root Pattern: 4× Tension Yields 2× Frequency

SquareRootRelationship PatternRecognition MathematicalDiscovery TensionFrequency
01:04

Pattern analysis reveals frequency doubles when tension quadruples (×4 → ×2) and triples when tension increases ninefold (×9 → ×3), identifying square root as the connecting operation.

Mersenne's Second Law: Frequency Proportional to Square Root of Tension

MersennesSecondLaw TensionFrequency SquareRootProportionality PhysicalLaws
04:41

Experimentally validated relationship—frequency of vibrating string is directly proportional to square root of tension (f ∝ √T)—known as Mersenne’s Second Law, another hidden connection between mathematics and physical reality.

Retroactive Testing: Validating Rules Against Existing Observations

RetroactiveTesting DataValidation ModelFitting InternalConsistency
06:40

When unable to generate new test data (limited to six guitar string types), the method tests proposed rules by making “predictions” for already-observed data points—if predictions match observations, the rule is probably correct.

Mathematics as Discovery Tool: Beyond Staring at Data

MathematicalAnalysis DiscoveryMethod DataAnalysis QuantitativeReasoning
06:48

Rather than “staring down data and hoping for magical insights” when patterns aren’t obvious, mathematics provides systematic tools for testing hypotheses and revealing hidden relationships.

Failed Hypothesis: Inverse Mass Proportionality Rejected (70% Error)

HypothesisFailure MassFrequency LargeError ScientificIteration
07:44

The initial guess—frequency inversely proportional to mass per unit length (f = K/M)—produces predictions up to 70% off from observations, far exceeding the ~5% error tolerance from previous laws.

Iterative Refinement: Systematically Modifying Failed Hypotheses

IterativeRefinement SystematicModification HypothesisEvolution ScientificStrategy
08:29

Rather than random guessing among “thousands of possible rules,” systematic refinement identifies what works (inverse relationship), what fails (too-rapid increase), and modifies accordingly—applying square root to slow growth rate.

Square Root of Mass: Reducing Error from 70% to 4.7%

SquareRootMass ErrorReduction SuccessfulRefinement MathematicalSolution
10:50

The refined hypothesis—frequency inversely proportional to square root of mass per unit length (f = K/√M)—dramatically improves predictions, reducing maximum error from 70% down to 4.7%.

Mersenne's Third Law: Frequency Inversely Proportional to Square Root of Mass

MersennesThirdLaw MassFrequency InverseSquareRoot AcousticLaws
11:22

The experimentally validated relationship—frequency inversely proportional to square root of mass per unit length (f ∝ 1/√M)—completes Mersenne’s three laws governing vibrating strings.

Unified String Equation: Combining Three Laws into Complete Formula

UnifiedEquation ComprehensiveModel MathematicalSynthesis ThreeLawsCombined
11:40

The three Mersenne laws combine into a single comprehensive equation: f = K/(L√M) × √T, or more elegantly f = (1/L)√(T/M), providing complete mathematical description of string vibration frequency.