Everyone 
keeps asking me:
“What science-magic
makes a car fly?”

First: a viral
claim is not a flight
test. But the
cold-gas idea? We
can explain that.

I’m Moly Moly.
Chemistry scientist.
Professional
question-asker.

The green hair?
My own plant-derived
dye. The singed coat?
Also my work.

But a cold-gas
thruster is more
engineering art than
chemistry trick.

No
combustion 
reaction. Just stored
pressure, controlled
flow, and a very
purposeful exit.

So I’m passing
this one to Zhu Zhu—
my closest friend since
childhood, back home
in Chengdu.

Hello! And that leaf
is still attached to
my inventory.

He built go-karts
from scrap. I made
“potions” from
kitchen ingredients.

His inventions
rolled. Mine mostly
overflowed.

After a workshop
accident damaged
his arm, I helped
with the first-aid supplies
while a grown-up
helped us.

He rebuilt the arm.
We kept building the
friendship.

That’s his
Panda Grip. It
started as a way
to help me hold
delicate
glassware.

Then jars. Then
rescued cats.
Modularity is a
lifestyle.

And apparently
leaf security.

You know
renowned
geologist Alistair’s
prosthetic hand? Zhu
Zhu built that, too.

Adaptive fingers.
Field tools. Built
to be repaired, not
replaced.

And Alistair brings
it to me for routine
maintenance.

Genius designs
still need clean
joints and regular
checks.

Exactly. Mzee
keeps the fieldwork
moving.

Right. My workshop,
my explanation.

Cold-gas thruster:
no magic, just
plumbing—with
serious pressure-vessel
engineering.

I’ll supervise
the snacks.

Start with stored pressurized
gas—often nitrogen. A
regulator can reduce and
stabilize its supply pressure.

Open a valve, and
the gas expands
through a nozzle.
Some stored energy
becomes directed
exhaust motion.

“Cold” means no combustion
or deliberate heating here—
not necessarily icy gas.

Gas gains momentum
one way. The vehicle
gains momentum the
other way.

That’s conservation
of momentum. The
nozzle doesn’t need
air to push against—
it works in vacuum, too.

Meanwhile, my
spoon has gained
absolutely no leaf.

A force through the center
of mass changes motion
without adding a turning effect.

An off-center thrust
also creates torque:
a turning effect.

Carefully timed little pulses
can point a spacecraft. More
flow usually means more
thrust; longer pulses deliver
more impulse.

SpaceX uses cold
nitrogen gas on
Falcon 9’s second
stage for pointing
and roll control.

Small steering
nudges—not the main
engine that launches
the rocket!

Different jobs,
different propulsion
systems.

Could gas jets lift a car? In
principle—if upward thrust
exceeds its weight.

But hovering keeps spending gas.
Tanks add mass, gas runs out,
and cold gas usually gives less
impulse per kilogram than
combustion rockets.

Great for modest spacecraft nudges.
Sustained car flight is a much tougher
job—and pressure tanks are not DIY toys.

So: finite
gas, serious
engineering,
infinite leaf
defenses.

No magic.
Stored gas, a valve, a
nozzle—and a friend
who explains the
plumbing.

And a friend who
could simply ask for
a leaf.

May I borrow one for
chromatography?

Yes. See? The simplest
valve is communication.