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The Coastal Paradox Tara T. Craig MAA Session on It’s Circular: Conjecturee Compute, Iterate Joint Mathematics Meeting 2019 January 18, 2019

The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

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Page 1: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

The Coastal ParadoxTara T. Cra ig

MAA Sess ion on It ’s Cir cu la r : Con ject u ree Com p u t e, It er a t e

Jo in t Mat h em at ics Meet in g 20 19Jan u ary 18 , 20 19

Page 2: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

CCU- Math Teachers’ Circle● Started in August 2016● Middle School and High School Teachers● Create accessible activities for our audience.● Attended a session at Smokey Mountain MTC ● 3 Counties surrounding Myrtle Beach, SC

○ Tourist Beach town

Presenter
Presentation Notes
Low entry, high threshold
Page 3: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Hula Hoop Island

● Challenged to measure the hula hoop

● Varying ruler length, collect data

● What happens as the ruler gets smaller and smaller?

● Findings: 2𝜋𝜋r

● Conjecture: The smaller the ruler, the more precise the measurement.

Page 4: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Coastline

● How could we measure the coastline?

● Come up with questions○ What is coastline?○ Smaller rulers are more precise.○ How to physically do it? (too long)

Presenter
Presentation Notes
Questions: What is the coastline? Is it where the water meets the sand? Sand dunes? Need a model.
Page 5: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Measure the SC Coastline

Presenter
Presentation Notes
Created a model
Page 6: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Measure the SC Coastline

● Created a model and tested our conjecture.

● Growing at a rate larger than 1.

● Challenged their earlier conjecture.

● ‘Infinite’ complexity

● What in the heck is the length of the coastline?

Presenter
Presentation Notes
95,471 statute miles
Page 7: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

The Coastal Paradox

● A coastline’s complexity changes with measurement scale. This results in a coastline behaving more like a fractal than a smooth curve.

Presenter
Presentation Notes
Discover this infinite coastline of their coast. But, is this enough to challenge their original conjecture? More examples of infinite lengths… cantar dust.
Page 8: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Koch Curve and Snowflake

● Collected more data

● Iterated :)

● Size, Scale, Number of pieces, and length

● Computed Area/Perimeter

● Compared characteristics of fractals to our coastline

Page 9: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Extension: Fractal Dimensions

Presenter
Presentation Notes
Solved for D and discovered Hausdorff Dimension formula.
Page 10: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Exploring Dimensions

Page 11: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Takeaways

● Context to explore size, scale, dimensions (Middle Level)

● Engaging students in math exploration with fractals (Frozen)

● Fun use of logarithms.

● Infinite sequences and series

● Fractals are fun!

Page 12: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Resources

● https://sites.google.com/view/taracraig

● Burger, Edward and Starbird, Michael. The Heart of Mathematics: An Invitation to Effective Thinking. 2013. Print.

● Measuring Coastline Numberphile https://www.youtube.com/watch?v=7dcDuVyzb8Y

● Special thanks to Julie Barnes of Western Carolina University!

Page 13: The Coastal Paradox - MAAsigmaa.maa.org/mcst/documents/TheCoastalParadox.pdf · 2019-01-19 · The Coastal Paradox A coastline’s complexity changes with measurement scale. This

Questions?

Tara T. Craig ([email protected])