Football Physics: The Science Behind a Perfect Spiral | NFL Films Presents

[Music]

i've studied this ball for most of my

life

the placement of the laces

the tightness of a spiral pass

velocity acceleration torque

striving for a total grasp of the

subject

i've learned and taught so much about

the unique magic of the american

football and still

after all these years there was one

question i couldn't answer

my name is dr timothy gay

i knew i wanted to be a physicist when i

was in third grade and football's been a

part of my life even longer

watching those nfl films highlights in

the church basement after a potluck

supper i was mesmerized by the tight

spiral coming right at me as if i could

reach out my hands and catch him

i wasn't good enough to make my prep

school football team but i'll tell you

someone who was

i call him bill but to most he's coach

belichick

i got to know bill during my two years

at phillips academy where i served

officially as a team's manager and

unofficially as its football physicist

in 1993 these two passions collided

head-on when i began teaching physics

here at the university of nebraska in

lincoln we experienced time in a

completely different way than we

experienced space it was a far cry from

my own college experience at caltech

where the standard student uniform was

pocket protectors and thick glasses

you see

the football team at caltech was

notoriously bad so bad that even i could

make it

in nebraska football is a way of life i

was in heaven

and i was a shameless self-promoter so i

couldn't have said yes fast enough when

nebraska's video team asked me if i

teach a football physics class at every

home game

[Applause]

if isaac newton's lab was the model of

scholarly isolation i'd begun teaching

the world's largest physics class

physics with unl physics professor dr

tim

90 000 students listened intently as i

explained how vectors can help predict

the direction of a roll-out pass or how

good footing on a tackle creates enough

downward force to transmit a huge hit

the best way to teach science is to

relate it to something people actually

care about

and what a lot of people care about

especially in nebraska is football

something tells me i'd better tackle a

different topic today in 2005 i took

everything i'd learned and put it into a

book

i even got my buddy bill to write the

introduction

the line of scrimmage things were really

taking off an area of battle where the

game can be won or lost but after all

the lectures and lessons there was still

that one question i couldn't answer and

it came back to the thing that had

captivated me in the first place

the perfect spiral pass

is there a more beautiful sight in all

of sports

[Music]

if you get a bunch of physicists in a

room this is the question that confounds

them

none of us could make sense of why the

ball does what it does in the air

so perfect and to me

so vexing

here's the problem when the quarterback

throws the ball it's pitched up it

spirals as it moves down the field but

when it's caught it's pitched down

common sense and simple physics would

seem to dictate that the ball should

tumble end over end as it moves through

the pass or that it should maintain a

fixed axis as it was thrown as it moves

to the receiver

for years i couldn't figure it out

why does the football make that perfect

rainbow i enlisted the help of

colleagues from around the country

finally in 2020 after nearly two decades

we found the answer

it all comes back to a simple overlooked

physics principle gyroscopic procession

it's something kids learn about

intuitively when they spin a top or a

dreidel

if i put one end of a football on a

table tilt it and then release it

it falls over but if i take the ball and

spin it up

and release it from an angle as before

the ball doesn't fall over its tip

executes a circular motion about a

vertical line

a tight spiral pass turns over for the

same reason that the point of our

spinning football on the table top

precesses around the center the gist of

it is air drag takes the place of our

tabletop defining a new center about

which the ball processes

it's a lot more complicated than that

but in the interest of time i'll spare

you the details

it's published all right here in the

american journal of physics

as a scientist solving a problem that's

plagued you for years is like well

winning the super bowl

practice makes perfect

actually practice does not make perfect

only perfect practice makes perfect

vince lombardi said that

he also said they call it coaching

but it's teaching you do not just tell

them you show them the reasons

eric's hand puts spin on the ball to

stabilize it in flight for maximum

yardage unfortunately understanding the

theoretical principle of symmetry

doesn't guarantee instant success as a

quarterback

hey doc you got a chance to evaluate

your arm and uh i think you're better

suited for the offensive line

hey doc thanks for all that science you

taught me

you still got it eric

i'm often asked if the things i've

learned over the years can give a team

the upper hand

can they influence who will win the

short answer is no

the long answer well

that's a lecture in itself

you see most of this is instinctive to

football players they are truly

intuitive when it comes to the big hits

the long throws the short bursts of

speed

the game's greatest coaches and players

know how to use physics to their

advantage even if they know nothing

about physics itself

you'll appreciate the game more if you

understand the science behind it

[Music]

in all my years immersed in the game of

football i've never run out of a mammoth

sized tunnel

i've never thrown the biggest block

or scored the winning touchdown and

heard the roar of 90 000 fans

[Applause]

but up on those jumbotrons i got to be

their physics teacher that was even

better

[Applause]