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Can a Solar Still Generate Enough Fresh Water for Survival? | MythBusters

Adam: WE'RE STRANDED ON A DESERTED ISLAND

WITH NOTHING BUT SEVERAL MILES OF DUCT TAPE.

I'M FEELING PRETTY OPTIMISTIC ABOUT OUR CHANCES FOR SURVIVAL.

[ DING! ]

Narrator: ADAM GRABS SOME DUCT TAPE

AND SETS OFF TO TRY TO FIND DRINKABLE WATER.

[ LAUGHS ]

CLEARLY, THESE PLANTS ARE ALL GETTING

THEIR WATER FROM SOMEWHERE. I JUST NEED TO FIND IT.

Narrator: BY FOLLOWING THE LUSHER VEGETATION,

HE HOPES TO INCREASE HIS CHANCES OF FINDING A WATER SOURCE,

BUT IT'S STILL NO WALK IN THE PARK.

I'VE BEEN WALKING AROUND FOR A WHILE...

[ BREATHING HEAVILY ]

...AND I STILL HAVEN'T FOUND ANY WATER.

AND WHAT WE HAVE HERE IS A CLASSIC CATCH-22.

[ SIGHS ] I NEED WATER,

AND I'M BURNING THROUGH A LOT OF IT

JUST TO TRY AND FIND WATER.

IF I DON'T FIND IT SOON, IT'S GONNA BE BAD.

Narrator: SO, LET'S HOPE JAMIE CAN DO BETTER.

Jamie: IT'S HOT OUT HERE, AND I'M THIRSTY.

I GOT WATER EVERYWHERE BUT NOT A DROP TO DRINK.

EXCEPT I CAN MAKE FRESH WATER OUT OF THIS SALT WATER

WITH THE SUN'S HELP AND SOME DUCT TAPE.

Narrator: IT MAY SOUND AS THOUGH JAMIE'S BEEN IN THE SUN TOO LONG...

Jamie: IT'S ALREADY GETTING MOIST.

Narrator: ...BUT HIS "FRESH WATER FROM SALT WATER" IDEA

IS ROOTED IN REALITY.

I FOUND WATER!

Narrator: HE'S GOING TO BUILD A DEVICE CALLED A SOLAR STILL,

WHICH IS CONSIDERABLY MORE COMPLICATED

THAN FINDING SALTY WATER IN A SANDY HOLE.

Jamie: A SOLAR STILL USES THE SUN'S RAYS AND CONDENSATION

TO COLLECT WATER AND HERE'S HOW.

THE HOLE I'VE DUG IS DEEP ENOUGH THAT IT'S WET WITH SALT WATER.

AT THE BOTTOM, I'LL PLACE A COLLECTION CUP

THAT I'VE MADE FROM DUCT TAPE,

AND ABOVE THE HOLE, I'M GONNA PUT SOME CLEAR PLASTIC SHEETING.

THE HOT SUN SHINES THROUGH THAT

AND EVAPORATES THE WATER FROM THE SAND,

LEAVING THE SALT BEHIND.

THE WATER VAPOR THEN CONDENSES

ON THE COOL INSIDE OF THE PLASTIC SURFACE

AND DRIPS DOWN INTO THE CUP AS PURE, DRINKABLE WATER.

THAT'S THE THEORY AT LEAST.

LET'S SEE HOW WELL IT WORKS.

Narrator: WELL, HAVING MADE HIS WELL AND TAPED UP A COLLECTION CUP...

Jamie: WELL, THERE IT IS. GUARANTEE IT'S WATERPROOF.

Narrator: ...ALL THAT'S MISSING IS THE CLEAR PLASTIC OVERSHOOT.

AND FOR THAT, JAMIE IS BENDING THE DUCT-TAPE RULES.

Jamie: I'M MAKING A DUCT-TAPE SPIDER WEB AS A FRAMEWORK

WITH WHICH TO HOLD TOGETHER THIS STUFF -- SHRINK-WRAP.

NOW, I KNOW WHAT YOU'RE SAYING.

IT'S NOT DUCT TAPE, SO WHY ARE WE USING IT?

WELL, IT DID COME ON THE DUCT-TAPE PALLET.

I DON'T KNOW WHAT I'M GONNA USE THIS STUFF FOR,

BUT I BET YOU IT'S GONNA COME IN REAL HANDY.

AND, YOU KNOW, IT'S SURVIVAL.

WE'VE GOT TO USE EVERYTHING AT OUR DISPOSAL.

THE THING IS THAT ALL THESE LITTLE PIECES

DON'T REALLY HELP US SO MUCH, BUT ONCE THEY'RE HELD TOGETHER

INTO ONE BIG SHEET, WE'RE GOLDEN.

THERE WE GO.

HOPEFULLY, I DIDN'T USE MORE WATER MAKING IT

THAN IT'LL MAKE FOR ME.

[ LAUGHS ]

Narrator: THE LAST STEP IS

TO CAREFULLY POSITION THE SHEET OVER THE HOLE.

THERE WE GO. THAT'S THE TICKET.

Narrator: AND ALMOST IMMEDIATELY, THERE ARE ENCOURAGING SIGNS.

ALL THAT FOG THAT YOU CAN ALREADY SEE

FORMING ON THE UNDERSIDE OF THE PLASTIC

IS WHAT THIS IS ALL ABOUT.

IT'S PICKING UP THE MOISTURE FROM THE DAMP SAND,

WHICH IS EVAPORATING, COLLECTING ON THE PLASTIC,

AND EVENTUALLY, THOSE WILL FORM LARGER AND LARGER DROPLETS,

WHICH WILL RUN DOWNHILL INTO MY COLLECTION CONTAINER.

NOW WE JUST HAVE TO WAIT.

Narrator: IT'S THE MOMENT OF TRUTH -- TWO HOURS COOKING IN THE MIDDAY SUN.

WHAT'S THE VERDICT?

[ SIGHS ] WELL, THERE IT IS.

THAT'S PURE WATER, BUT THAT'S LIKE 1/4 OF A CUP.

WITH LESS THAN 5% OF THEIR DAILY WATERY NEEDS,

IT'S A DISAPPOINTING RESULT.

Jamie: WHY DOES EVERYTHING HAVE TO BE SO DIFFICULT?

Narrator: BUT BACK AT THE RUMBLE IN THE JUNGLE,

ADAM'S WELLING UP WITH EXCITEMENT.

MM! IT'S FRESH!

ALL RIGHT, WATER BOTTLES.

HALF MY TASK IS DONE.

I HAVE FOUND FRESH WATER, NO SMALL FEAT,

AND THAT'S REALLY IMPORTANT FOR OUR SURVIVAL.

NOW I SIMPLY HAVE TO GET IT BACK.

Narrator: THAT'S SOMETHING THAT'S NOT AS EASY AS IT SOUNDS.

I WOULD KILL FOR A WORKBENCH RIGHT ABOUT NOW.

Narrator: ADAM'S MAKING A KIND OF TUBULAR BOTTLE

THAT SHOULD HOLD ABOUT 10 PINTS OF WATER,

PROVIDED, OF COURSE, THAT IT DOESN'T LEAK.

IF I GET A SINGLE WRINKLE IN THIS SEAM,

IT'S A PLACE WHERE WATER CAN GET OUT -- CAN'T HAVE THAT.

WATER'S GOT TO GO FROM THE POND INTO HERE INTO HERE.

Narrator: IT'S A PAINSTAKING OPERATION, BUT EVENTUALLY,

THERE'S ONLY ONE THING LEFT TO DO.

OH! OH! OH!

IT'S COLD!

Narrator: FILL IT UP.

FILL UP, BABY. COME ON!

PLEASE HOLD UP.

FIRST IMPRESSIONS ARE GOOD.

[ LAUGHING ]

IT'S WORKING!

Narrator: AND SECOND IMPRESSIONS ARE EVEN BETTER.

IT SEEMS TO BE HOLDING!

[ LAUGHS ]