Bill Ames - Snowflake Formation - G4G14 Apr 2022

Summary

In this talk, the speaker and his son explore how snowflakes form by identifying three physical rules that guide their creation. Using a simulator, they demonstrate how snowflakes form hexagonal structures due to freezing, with temperature changes influencing branching patterns. The process also explains why some hexagons detach as snowflakes grow, based on weak connections and size mismatches. By adjusting temperature over time, the speaker shows how complex and diverse snowflake patterns emerge. Attendees are invited to explore the simulator during the break.

Takeaways

• 🌨️ The presenter discusses the natural process of snowflake formation and shares a collaboration with his son to understand it.
• 🔬 They identified three self-evident physical rules that govern the formation of snowflakes.
• ❄️ Rule one: Freezing water in clouds forms hexagonal shapes, as demonstrated by the structure of ice 11.
• 💻 A simulator was created to visualize the formation of snowflakes based on the identified rules.
• 🌡️ Rule two: Temperature fluctuations within clouds affect the growth of snowflakes, causing gaps and branches.
• 🔗 Rule three: The structural integrity of snowflakes is influenced by the connections between hexagons; weak connections can lead to the loss of hexagons.
• 📉 The simulator allows for the control of temperature during the snowflake formation process, demonstrating how rapid temperature drops can lead to branching.
• 🔄 The presenter shows how the simulator can be used to add generations of hexagons, each colder and smaller, leading to the characteristic snowflake shape.
• 📸 Historical photographs of snowflakes from 1910 are used to validate the simulator's accuracy in replicating natural snowflake patterns.
• 🎮 An interactive mode in the simulator allows users to manipulate the temperature sequence, creating different snowflake designs.
• 🤝 The presenter invites the audience to interact with the simulator during the break to explore snowflake formation further.

Q & A

What is the main topic of the discussion in the script?

The main topic of the discussion is the process by which snowflakes form and the physical rules that govern their unique shapes.

What is the first rule mentioned for snowflake formation?

The first rule is that freezing water in clouds forms hexagons, as demonstrated by the structure of ice 11.

How does the simulator demonstrate the first rule?

The simulator demonstrates the first rule by creating a hexagonal lattice pattern, which is a honeycomb structure, by adding hexagons to unpaired edges.

What is the second rule that influences snowflake formation?

The second rule is the control over temperature as the snowflake forms, which can cause gaps and branches to form due to rapid temperature changes.

How does the simulator represent the temperature changes?

The simulator represents temperature changes on a graph, with the vertical axis representing temperature and the horizontal axis representing generation number.

What is the third rule that affects how snowflakes form?

The third rule is about the structural integrity of the snowflake. Small hexagons cannot merge with larger ones due to edge length ratios, and connections at single vertices are weak and can break away.

Why do some hexagons fall off the snowflake in the simulation?

Some hexagons fall off the snowflake in the simulation because they cannot merge with others if the edge length ratios are too different, or because they are connected at only one vertex, making the connection weak and prone to breaking.

What additional feature was added to the simulator for user interaction?

An automatic mode was added to the simulator, allowing users to change the sequence of temperatures the snowflake goes through during formation, which affects the final shape of the snowflake.

What is the significance of the 1910 snowflake photographs mentioned in the script?

The 1910 snowflake photographs are significant as they provide historical evidence of snowflake shapes, including hexagonal structures and early stages of branching.

How does the speaker intend to make the simulator more engaging for users?

The speaker intends to make the simulator more engaging by allowing users to interact with it during breaks, offering the opportunity to experiment with different temperature sequences and observe the resulting snowflake shapes.

What is the ultimate goal of the simulation described in the script?

The ultimate goal of the simulation is to replicate and demonstrate the natural process of snowflake formation, illustrating how the three physical rules lead to the diverse and intricate shapes of snowflakes.

Outlines

00:00

🌨️ The Science of Snowflake Formation

The speaker introduces a collaborative project with his son, Scott, to understand the natural process of snowflake formation. They discovered three self-evident physical rules that govern this process. The first rule is that freezing ice in clouds forms hexagonal shapes, as illustrated by the structure of ice 11. A simulator is used to demonstrate this rule, creating a honeycomb pattern by adding hexagons to unpaired edges. The speaker then transitions to explaining the branching out of snowflakes, hinting at the influence of cloud conditions such as updrafts, downdrafts, and temperature variations on the formation of snowflakes.

05:00

🌡️ Simulating Snowflake Growth with Temperature Control

The speaker elaborates on the second rule of snowflake formation, which involves controlling the temperature as the ice flake forms. Using the simulator, he shows how rapidly decreasing temperatures can lead to gaps in the formation of hexagons, which is a crucial step towards the development of snowflake branches. The third rule discussed is the structural integrity of hexagons, where small hexagons cannot merge with larger ones due to edge length ratios, and weak connections at single vertices can lead to the loss of hexagons. The speaker demonstrates this through the simulator, showing how these rules lead to the formation of a snowflake. He concludes by inviting the audience to interact with the simulator during the break to explore different temperature sequences and their effects on snowflake shapes.

Keywords

💡Snowflakes

Snowflakes are a natural phenomenon where ice crystals form in the atmosphere, creating unique and intricate patterns. In the video, the speaker and his son are exploring the science behind how snowflakes form their distinctive shapes. The video aims to understand the 'rules' that nature follows to create these beautiful and complex structures.

💡Hexagonal Shapes

Hexagonal shapes are six-sided figures with all internal angles equal to 120 degrees. In the context of the video, the speaker mentions that ice forms hexagonal lattices when it freezes, which is the first rule they identify in the process of snowflake formation. This is illustrated when the speaker shows a simulator generating hexagonal patterns.

💡Self-Evident Physical Rules

These are fundamental principles that govern the natural processes, in this case, the formation of snowflakes. The video discusses three such rules that the speaker and his son have identified to explain how snowflakes grow their unique shapes. These rules are used to create a simulation that mimics the natural process.

💡Ice 11

Ice 11 is a specific crystalline structure of ice that forms under certain conditions, such as when water vapor turns directly into a solid without becoming liquid first. The video uses Ice 11 as an example to highlight the hexagonal pattern that is the basis for the first rule of snowflake formation.

💡Simulation

In the video, the term 'simulation' refers to the computer program created by the speaker and his son to model the rules of snowflake formation. The simulation is used to visually demonstrate how the rules lead to the development of the complex structures seen in real snowflakes.

💡Updrafts and Downdrafts

These are vertical air currents that occur within clouds and are crucial to the formation of snowflakes. Updrafts carry snowflakes upward into colder regions where they can grow, while downdrafts can cause them to melt or break apart. The video mentions these as part of the complex environment inside a cloud where snowflakes form.

💡Temperature Gradient

A temperature gradient refers to the change in temperature with respect to position or time. In the video, the speaker discusses controlling the temperature as a key factor in the simulation, with colder temperatures leading to smaller and more numerous hexagons, which is part of the second rule in snowflake formation.

💡Generations

In the context of the video, 'generations' refer to the iterative process of adding more hexagons to the simulation based on the rules identified. Each generation represents a step in the growth of a snowflake, with the simulator adding hexagons to unpaired edges to mimic the branching patterns seen in real snowflakes.

💡Hydrogen Bonds

Hydrogen bonds are a type of chemical bond that plays a significant role in the structure of water and ice. In the video, the speaker mentions that the bonds between hexagons in the simulation are weak, which can lead to the breaking off of hexagons, contributing to the unique shapes of snowflakes. This is part of the third rule discussed.

💡Planar and Structural Integrity

This concept refers to the stability and flatness of the snowflake's structure. The video explains that for a hexagon to remain part of the snowflake, it needs to be connected at three vertices to maintain its planar and structural integrity. This is important for understanding why some hexagons may fall off during the formation process.

Highlights

A collaboration between the speaker and his son Scott to explore the formation of snowflakes.

The identification of three self-evident physical rules that describe the process of snowflake formation.

Rule one: Freezing water in clouds forms hexagons, as demonstrated by the structure of ice 11.

A simulator was created to simulate the formation of hexagonal ice structures.

The simulator adds hexagons to form a honeycomb structure, which is a basic snowflake shape.

The upper left snowflake in a 1910 photograph shows the beginning of spine growth from a hexagonal base.

The second rule involves controlling the temperature as the snowflake forms, which affects its structure.

The temperature drop during snowflake formation can cause gaps and branching in the structure.

The third rule explains why some hexagons fall off: weak connections and the need for at least three vertices for stability.

The simulator demonstrates how the three rules lead to the formation of complex snowflake patterns.

An automatic mode in the simulator allows for real-time adjustments and observations of snowflake formation.

The speaker invites the audience to interact with the simulator during the break to explore different snowflake designs.

The simulator provides a fun and educational tool for understanding the science behind snowflake formation.

The presentation concludes with applause, indicating the audience's appreciation for the informative and engaging content.

Transcripts

foreign

[Music]

made it on the list I want to let you

know this is very much a collaboration

between me and my son Scott raise your

hand Scott so I drew the Short Straw so

I'm up here talking but

um

we've all seen beautiful snowflakes and

the question we were trying to answer

was how does nature do it what are the

rules and we've found a set of three

self-evident physical rules that

describe the process

so I want to show those rules to you the

first one I'm going to steal from

chemists this is a picture of ice 11

from a Wikipedia page this is the

structure that that ice forms when it

goes directly from water vapor to a

solid so what I what I want to emphasize

here is that it forms hexagonal shapes a

whole

hexagonal lattice that's going to be our

first rule freezing watt freezing ice in

the clouds forms hexagons

so now I want to shift over to a

simulator that we've written that's

going to simulate that rule and the

other two which you're about to follow

and you can see the well that's that's a

hexagon and if I add more hexagons to it

I'm going to add what I call a

generation put a hexagon on every

unpaired edge up there and the program

automatically zooms out so you can see

everything

so I'm going to just add some more

Generations

and what you get is this nice honeycomb

structure

and

that doesn't look like a snowflake does

it well technically it does look like a

snowflake because here's a photograph of

some snowflakes taken in 1910 and I want

to call your attention to the upper left

one which is starting to grow some

spines but basically it's a hexagon and

if you look at photographs of snowflakes

that the photographer has not selected

the pretty ones from you'll see some

hexagons in there but we really want to

know what causes them to Branch out

well this is happening inside of a cloud

there are a lot of things going on

inside of a cloud you've got updrafts

and downdrafts you've got warm fronts

meaning cold fronts

cold fronts

ice just like everything else shrinks

when it gets colder

what if the temperature is dropping

while the snowflake is forming

so that's the second thing we want to

add to this simulation is control over

the temperature as the ice flakes ice

snowflake forms so the bottom half of

this

simulation is input to the program it's

temperature on the vertical vertical

axis generation number on the horizontal

axis so basically time and you can place

points here to show what you want the

temperature be to be as we add more

hexagons

now I can't simulate the 10 to the 23rd

molecules in a typical snowflake so in

order to see the effects quickly I'm

going to have to lower the temperature

very fast very quickly so let's start

adding Generations now where each one is

going to be a little colder and a little

smaller than the others following along

this graph and I don't know how well

that shows up there maybe if you're

close enough you can see some gaps

starting to form here

so something is going something has to

change if it's going to start putting

out spiers you can't just grow a big

honeycomb so let me go a little bit

farther and at least on mine I can see

the gaps are getting a little larger in

between and something interesting is

about to happen there we go

um if you can see that the

um

upper left and lower right Corners

there's a hexagon missing that's really

the third uh there's there's two reasons

for that one can really be the second

rule if you have a small hexagon that's

trying to merge with a big hexagon you

can't do it the edge length ratios are

just are just too far off it's a little

bit it can stretch but it's too far off

it can't do it the other thing that can

happen is if you have a hexagon joint

and another one at a single vertex it

can flop around all different ways it's

a very weak connection these are

hydrogen bonds in the first place which

are some of the weakest bonds that

chemists have and it'll get blown away

even if it's connected two places it can

flap back and forth and the third

dimension that's easy to get that's easy

to fall away you need to be connected at

least three vertices in order to remain

planar and structurally there so that's

why that's the third rule that can

explain while it's some of these hexes

are falling off so let's keep adding

Generations

and I'm going to speed up a little bit

[Laughter]

simulating those three rules

and that my friends is a snowflake

so to make this a little more fun to

play with we added this little automatic

mode where as you move the graph around

you can see you're changing the sequence

of temperatures that it goes through as

it's forming so you can see let's see

what the effects are and what sort of

snowflakes that creates if you'd like to

play with it I'll have my program over

there during the break and I'd be happy

to talk to you thank you

[Applause]