...and to slow down.

Friction is how we pick things up

...and hold on to them.

To be totally honest,

there isn't much we could do without friction!

A world without friction would be unlivable.

But, do you think you could function

for one minute without it?

The reason why friction is

so important to our world,

is because it affects everything that's in motion.

When any object is moving,

slipping or sliding in one direction,

friction is acting in the opposite direction.

So, for example, consider something

as simple as walking.

Your feet are pushing

backward against the ground,

and the ground reacts by pushing

forward on your foot,

allowing you to accelerate.

But it's a lot easier to walk on concrete

than it is to walk on ice, right?

That's because ice has a much lower

coefficient of friction than concrete.

In other words,

ice is much smoother than concrete,

so it has less resistance,

causing your feet to slip and slide.

The same example can be applied to vehicles.

In fact, car tires are designed

with friction in mind,

to optimize your safety, and to make sure that

you can turn and stop without skidding.

In dry conditions, having a tire

that's completely smooth

actually gives you better handling,

since there is more surface area

to generate frictional forces.

But the reason why your car's tires

probably have treads

is to improve traction in wet conditions.

When you're driving in rain or snow,

even a thin layer of water between the road

and your tire can cause you to lose control.

That's because there's less contact

between the tire and the road,

so the forces of friction can't work their magic!

But tires with treads have grooves

that divert the excess water,

so the rubber can connect with the road,

and you can drive safely.

Of course, there are plenty of other ways

to test how friction works.

Do some redecorating,

play a game of ice hockey,

or, light a match!

Yes, celebrate friction,

and be grateful it exists,

because you don't know what you've got

until it's gone for one minute.

Cut the fireworks.

Matches don't work any more,

and you can't use lighters.

In fact, you can't pick anything up,

because your ability to grip

and pick things up is due to friction.

Anything you were holding on to,

the moment friction ceased to exist,

would instantly fall to the ground

or fly out of your hand.

If you were walking when friction disappeared,

your legs would still work,

but you wouldn't go anywhere.

But if you were in a moving vehicle,

you'd keep going, and going,

and going, and going,

until you crashed into something!

Your brakes are friction.

In fact, for that one, seemingly endless,

minute of chaos and destruction,

terminal velocity would cease to exist,

meaning that anything in motion

would be a deadly projectile.

At least you wouldn't get rope burn...

But that tree, that penny,

that runaway train is

actually the least of your worries,

because within just one minute of losing friction

– actually, within an instant of losing friction –

the whole world would just become

one big, formless, featureless blob.

Considering that everything on Earth

is composed of atoms and particles,

and that all atoms and particles

are held together by friction,

If you've ever wondered why skidding cars

and baseball slides look so cool,

well, just be grateful for friction.

Yes, it can make life hard sometimes,

but, it beats losing literally

everything on this planet!

So go on, try it for yourself.

Take a walk, and feel the friction

between your feet and the ground.

But don't go too far!

Double back quickly for

another episode of "What If!"