This is an essay my father would have liked. Or maybe he would have been dismissive and said, e toh shobai janey, lekhbar ki achhe, or, the guy is too full of himself. But the world is ending, it seems, and so it's OK if I am offering up other people's writing for a non-existent person to read.
For you, baba. Dear father. Pater.
I miss you so much. I feel so scared. I don't know where we will end up. I also think that you might have felt as exposed, as left to find your way by yourself at my age.
I wish you had grown old with me. I wish you sat in a reclining chair, with hair iron-grey by now, and read. But I am also sure you would have driven me crazy.
"Surely You're
Joking, Mr. Feynman!"
Adventures of a Curious Character
by Richard P. Feynman
He Fixes Radios by Thinking!
When I was about eleven or
twelve I set up a lab in my house. It consisted of an old wooden packing box
that I put shelves in. I had a heater, and I'd put in fat and cook french-fried
potatoes all the time. I also had a storage battery, and a lamp bank.
To build the lamp bank I went
down to the five-and-ten and got some sockets you can screw down to a wooden
base, and connected them with pieces of bell wire. By making different
combinations of switches--in series or parallel--I knew I could get different voltages.
But what I hadn't realized was that a bulb's resistance depends on its
temperature, so the results of my calculations weren't the same as the stuff
that came out of the circuit. But it was all right, and when the bulbs were in
series, all half-lit, they would gloooooooooow, very pretty--it was
great!
I had a fuse in the system so
if I shorted anything, the fuse would blow. Now I had to have a fuse that was
weaker than the fuse in the house, so I made my own fuses by taking tin foil
and wrapping it around an old burnt-out fuse. Across my fuse I had a five-watt
bulb, so when my fuse blew, the load from the trickle charger that was always
charging the storage battery would light up the bulb. The bulb was on the
switchboard behind a piece of brown candy paper (it looks red when a light's
behind it)--so if something went off, I'd look up to the switchboard and there
would be a big red spot where the fuse went. It was fun!
I enjoyed radios. I started
with a crystal set that I bought at the store, and I used to listen to it at
night in bed while I was going to sleep, through a pair of earphones. When my
mother and father went out until late at night, they would come into my room
and take the earphones off--and worry about what was going into my head while I
was asleep.
About that time I invented a
burglar alarm, which was a very simple-minded thing: it was just a big battery
and a bell connected with some wire. When the door to my room opened, it pushed
the wire against the battery and closed the circuit, and the bell would go off.
One night my mother and father
came home from a night out and very, very quietly, so as not to disturb the
child, opened the door to come into my room to take my earphones off. All of a
sudden this tremendous bell went off with a helluva racket--BONG BONG BONG BONG
BONG!!! I jumped out of bed yelling, "It worked! It worked!"
I had a Ford coil--a spark coil
from an automobile--and I had the spark terminals at the top of my switchboard.
I would put a Raytheon RH tube, which had argon gas in it, across the
terminals, and the spark would make a purple glow inside the vacuum--it was
just great!
One day I was playing with the
Ford coil, punching holes in paper with the sparks, and the paper caught on
fire. Soon I couldn't hold it any more because it was burning near my fingers,
so I dropped it in a metal wastebasket which had a lot of newspapers in it.
Newspapers burn fast, you know, and the flame looked pretty big inside the
room. I shut the door so my mother--who was playing bridge with some friends in
the living room--wouldn't find out there was a fire in my room, took a magazine
that was lying nearby, and put it over the wastebasket to smother the fire.
After the fire was out I took
the magazine off, but now the room began to fill up with smoke. The wastebasket
was still too hot to handle, so I got a pair of pliers, carried it across the
room, and held it out the window for the smoke to blow out.
But
because it was breezy outside, the wind lit the fire again, and now the
magazine was out of reach. So I pulled the flaming wastebasket back in through
the window to get the magazine, and I noticed there were curtains in the
window--it was very dangerous!
Well, I got the magazine, put
the fire out again, and this time kept the magazine with me while I shook the
glowing coals out of the wastepaper basket onto the street, two or three floors
below. Then I went out of my room, closed the door behind me, and said to my
mother, "I'm going out to play," and the smoke went out slowly
through the windows.
I also did some things with
electric motors and built an amplifier for a photo cell that I bought that
could make a bell ring when I put my hand in front of the cell. I didn't get to
do as much as I wanted to, because my mother kept putting me out all the time,
to play. But I was often in the house, fiddling with my lab.
I bought radios at rummage
sales. I didn't have any money, but it wasn't very expensive-they were old,
broken radios, and I'd buy them and try to fix them. Usually they were broken
in some simple-minded way--some obvious wire was hanging loose, or a coil was
broken or partly unwound--so I could get some of them going. On one of these
radios one night I got WACO in Waco, Texas--it was tremendously exciting!
On this same tube radio up in
my lab I was able to hear a station up in Schenectady called WGN. Now, all of
us kids-- my two cousins, my sister, and the neighborhood kids--listened on the
radio downstairs to a program called the Eno Crime Club--Eno effervescent
salts--it was the thing! Well, I discovered that I could hear this
program up in my lab on WGN one hour before it was broadcast in New York! So
I'd discover what was going to happen, and then, when we were all sitting
around the radio downstairs listening to the Eno Crime Club, I'd say, "You
know, we haven't heard from so-and-so in a long time. I betcha he comes and
saves the situation."
Two seconds later, bup-bup,
he comes! So they all got excited about this, and I predicted a couple of other
things. Then they realized that there must be some trick to it--that I must
know, somehow. So I owned up to what it was, that I could hear it upstairs the
hour before.
You know what the result was,
naturally. Now they couldn't wait for the regular hour, They all had to sit
upstairs in my lab with this little creaky radio for half an hour, listening to
the Eno Crime Club from Schenectady.
We lived at that time in a big
house; it was left by my grandfather to his children, and they didn't have much
money aside from the house. It was a very large, wooden house, and I would run
wires all around the outside, and had plugs in all the rooms, so I could always
listen to my radios, which were upstairs in my lab. I also had a
loudspeaker--not the whole speaker, but the part without the big horn on it.
One day, when I had my
earphones on, I connected them to the loudspeaker, and I discovered something:
I put my finger in the speaker and I could hear it in the earphones; I
scratched the speaker and I'd hear it in the earphones. So I discovered that
the speaker could act like a microphone, and you didn't even need any
batteries. At school we were talking about Alexander Graham Bell, so I gave a
demonstration of the speaker and the earphones. I didn't know it at the time,
but I think it was the type of telephone he originally used.
So now I had a microphone, and
I could broadcast from upstairs to downstairs, and from downstairs to upstairs,
using the amplifiers of my rummage-sale radios. At that time my sister Joan,
who was nine years younger than I was, must have been about two or three, and
there was a guy on
the
radio called Uncle Don that she liked to listen to. He'd sing little songs
about "good children," and so on, and he'd read cards sent in by
parents telling that "Mary So-and-so is having a birthday this Saturday at
25 Flatbush Avenue."
One day my cousin Francis and I
sat Joan down and said that there was a special program she should listen to.
Then we ran upstairs and we started to broadcast: "This is Uncle Don. We know
a very nice little girl named Joan who lives on New Broadway; she's got a
birthday coming--not today, but such-and-such. She's a cute girl." We sang
a little song, and then we made music: "Deedle leet deet, doodle doodle
loot doot; deedle deedle leet, doodle loot doot doo We went through the
whole deal, and then we came downstairs: "How was it? Did you like the
program?"
"It was good," she
said, "but why did you make the music with your mouth?"
One day I got a telephone call:
"Mister, are you Richard Feynman ?"
"Yes."
"This is a hotel. We have
a radio that doesn't work, and would like it repaired. We understand you might
be able to do something about it."
"But I'm only a little
boy," I said. "I don't know how--"
"Yes, we know that, but
we'd like you to come over anyway."
It was a hotel that my aunt was
running, but I didn't know that. I went over there with--they still tell the
story--a big screwdriver in my back pocket. Well, I was small, so any screwdriver
looked big in my back pocket.
I went up to the radio and
tried to fix it. I didn't know anything about it, but there was also a handyman
at the hotel, and either he noticed, or I noticed, a loose knob on the
rheostat--to turn up the volume--so that it wasn't turning the shaft. He went
off and filed something, and fixed it up so it worked.
The next radio I tried to fix
didn't work at all. That was easy: it wasn't plugged in right. As the repair
jobs got more and more complicated, I got better and better, and more
elaborate. I bought myself a milliammeter in New York and converted it into a
voltmeter that had different scales on it by using the right lengths (which I
calculated) of very fine copper wire. It wasn't very accurate, hut it was good
enough to tell whether things were in the right ballpark at different
connections in those radio sets.
The main reason people hired me
was the Depression. They didn't have any money to fix their radios, and they'd
hear about this kid who would do it for less. So I'd climb on roofs to fix
antennas, and all kinds of stuff. I got a series of lessons of ever-increasing
difficulty. Ultimately I got some job like converting a DC set into an AC set,
and it was very hard to keep the hum from going through the system, and I
didn't build it quite right. I shouldn't have bitten that one off, but I didn't
know.
One job was really sensational.
I was working at the time for a printer, and a man who knew that printer knew I
was trying to get jobs fixing radios, so he sent a fellow around to the print
shop to pick me up. The guy is obviously poor--his car is a complete wreck--and
we go to his house which is in a cheap part of town. On the way, I say,
"What's the trouble with the radio?"
He says, "When I turn it
on it makes a noise, and after a while the noise stops and everything's all
right, but I don't like the noise at the beginning."
I
think to myself: "What the hell! If he hasn't got any money, you'd think
he could stand a little noise for a while."
And all the time, on the way to
his house, he's saying things like, "Do you know anything about radios?
How do you know about radios--you're just a little boy!"
He's putting me down the whole
way, and I'm thinking, "So what's the matter with him? So it makes a
little noise."
But when we got there I went
over to the radio and turned it on. Little noise? My God! No wonder the
poor guy couldn't stand it. The thing began to roar and wobble--WUH BUH BUH BUH
BUH--A tremendous amount of noise. Then it quieted down and played
correctly. So I started to think: "How can that happen?"
I start walking back and forth,
thinking, and I realize that one way it can happen is that the tubes are
heating up in the wrong order--that is, the amplifier's all hot, the tubes are
ready to go, and there's nothing feeding in, or there's some back circuit
feeding in, or something wrong in the beginning part--the HF part--and
therefore it's making a lot of noise, picking up something. And when the RF circuit's
finally going, and the grid voltages are adjusted, everything's all right.
So the guy says, "What are
you doing? You come to fix the radio, but you're only walking back and
forth!"
I say, "I'm
thinking!" Then I said to myself, "All right, take the tubes out, and
reverse the order completely in the set." (Many radio sets in those days
used the same tubes in different places--212's, I think they were, or 212-A's.)
So I changed the tubes around, stepped to the front of the radio, turned the thing
on, and it's as quiet as a lamb: it waits until it heats up, and then plays
perfectly--no noise.
When a person has been negative
to you, and then you do something like that, they're usually a hundred percent
the other way, kind of to compensate. He got me other jobs, and kept telling
everybody what a tremendous genius I was, saying, "He fixes radios by thinking!"
The whole idea of thinking, to fix a radio--a little boy stops and thinks, and
figures out how to do it--he never thought that was possible.
Radio circuits were much easier
to understand in those days because everything was out in the open. After you
took the set apart (it was a big problem to find the right screws), you could
see this was a resistor, that's a condenser, here's a this, there's a that;
they were all labeled. And if wax had been dripping from the condenser, it was
too hot and you could tell that the condenser was burned out. If there was
charcoal on one of the resistors you knew where the trouble was. Or, if you
couldn't tell what was the matter by looking at it, you'd test it with your
voltmeter and see whether voltage was coming through. The sets were simple, the
circuits were not complicated. The voltage on the grids was always about one
and a half or two volts and the voltages on the plates were one hundred or two
hundred, DC. So it wasn't hard for me to fix a radio by understanding what was
going on inside, noticing that something wasn't working right, and fixing it.
Sometimes it took quite a
while. I remember one particular time when it took the whole afternoon to find
a burned-out resistor that was not apparent. That particular time it happened
to be a friend of my mother, so I had time-there was nobody on my back
saying, "What are you doing?" Instead, they were saying, "Would
you like a little milk, or some cake?" I finally fixed it because I had,
and still have, persistence. Once I get on a puzzle, I can't get off. If my
mother's friend had said, "Never mind, it's too much work," I'd have
blown my top, because I want to beat this damn
thing,
as long as I've gone this far. I can't just leave it after I've found out so
much about it. I have to keep going to find out ultimately what is the matter
with it in the end.
That's a puzzle drive. It's
what accounts for my wanting to decipher Mayan hieroglyphics, for trying to
open safes. I remember in high school, during first period a guy would come to
me with a puzzle in geometry, or something which had been assigned in his
advanced math class. I wouldn't stop until I figured the damn thing out--it
would take me fifteen or twenty minutes. But during the day, other guys would
come to me with the same problem, and I'd do it for them in a flash. So for one
guy, to do it took me twenty minutes, while there were five guys who thought I
was a super-genius.
So I got a fancy reputation.
During high school every puzzle that was known to man must have come to me.
Every damn, crazy conundrum that people had invented, I knew. So when I got to
MIT there was a dance, and one of the seniors had his girlfriend there, and she
knew a lot of puzzles, and he was telling her that I was pretty good at them.
So during the dance she came over to me and said, "They say you're a smart
guy, so here's one for you: A man has eight cords of wood to chop . . ."
And I said, "He starts by
chopping every other one in three parts," because I had heard that one.
Then she'd go away and come
back with another one, and I'd always know it.
This went on for quite a while,
and finally, near the end of the dance, she came over, looking as if she was
going to get me for sure this time, and she said, "A mother and daughter
are traveling to Europe . . ."
"The daughter got the
bubonic plague."
She collapsed! That was hardly
enough clues to get the answer to that one: It was the long story about how a
mother and daughter stop at a hotel and stay in separate rooms, and the next day
the mother goes to the daughter's room and there's nobody there, or somebody
else is there, and she says, "Where's my daughter?" and the hotel
keeper says, "What daughter?" and the register's got only the
mother's name, and so on, and so on, and there's a big mystery as to what
happened. The answer is, the daughter got bubonic plague, and the hotel, not
wanting to have to close up, spirits the daughter away, cleans up the room, and
erases all evidence of her having been there. It was a long tale, but I had
heard it, so when the girl started out with, "A mother and daughter are
traveling to Europe," I knew one thing that started that way, so I took a
flying guess, and got it.
We had a thing at high school
called the algebra team, which consisted of five kids, and we would travel to
different schools as a team and have competitions. We would sit in one row of
seats and the other team would sit in another row. A teacher, who was running
the contest, would take out an envelope, and on the envelope it says "forty-five
seconds." She opens it up, writes the problem on the blackboard, and says,
"Go!"--so you really have more than forty-five seconds because while
she's writing you can think. Now the game was this: You have a piece of paper,
and on it you can write anything, you can do anything. The only thing that
counted was the answer. If the answer was "six books," you'd have to
write "6," and put a big circle around it. If what was in the circle
was right, you won; if it wasn't, you lost.
One thing was for sure: It was
practically impossible to do the problem in any conventional, straightforward
way, like putting "A is the number of red books, B is the number of blue
books," grind, grind, grind, until you get "six books." That
would take you fifty seconds, because the people who set up the timings on
these problems had made them all a trifle short. So you had to think, "Is
there a way to see it?" Sometimes you could see it in a flash, and
sometimes you'd have to invent
another
way to do it and then do the algebra as fast as you could. It was wonderful
practice, and I got better and better, and I eventually got to be the head of
the team. So I learned to do algebra very quickly, and it came in handy in
college. When we had a problem in calculus, I was very quick to see where it
was going and to do the algebra--fast.
Another thing I did in high
school was to invent problems and theorems. I mean, if I were doing any
mathematical thing at all, I would find some practical example for which it
would be useful. I invented a set of right-triangle problems. But instead of
giving the lengths of two of the sides to find the third, I gave the difference
of the two sides. A typical example was: There's a flagpole, and there's a rope
that comes down from the top. When you hold the rope straight down, it's three
feet longer than the pole, and when you pull the rope out tight, it's five feet
from the base of the pole. How high is the pole?
I developed some equations for
solving problems like that, and as a result I noticed some connection--perhaps
it was sin2 + cos2 = 1--that reminded me of trigonometry. Now, a few years
earlier, perhaps when I was eleven or twelve, I had read a book on trigonometry
that I had checked out from the library, but the book was by now long gone. I
remembered only that trigonometry had something to do with relations between
sines and cosines. So I began to work out all the relations by drawing
triangles, and each one I proved by myself. I also calculated the sine, cosine,
and tangent of every five degrees, starting with the sine of five degrees as
given, by addition and half-angle formulas that I had worked out.
A few years later, when we
studied trigonometry in school, I still had my notes and I saw that my
demonstrations were often different from those in the book. Sometimes, for a
thing where I didn't notice a simple way to do it, I went all over the place
till I got it. Other times, my way was most clever--the standard demonstration
in the book was much more complicated! So sometimes I had 'em heat, and
sometimes it was the other way around.
While I was doing all this
trigonometry, I didn't like the symbols for sine, cosine, tangent, and so on.
To me, "sin f" looked like s times i times n times f! So I invented
another symbol, like a square root sign, that was a sigma with a long arm
sticking out of it, and I put the f underneath. For the tangent it was a tau
with the top of the tau extended, and for the cosine I made a kind of gamma,
but it looked a little bit like the square root sign.
Now the inverse sine was the
same sigma, but left-to-right reflected so that it started with the horizontal
line with the value underneath, and then the sigma. That was the inverse
sine, NOT sink f--that was crazy! They had that in books! To me, sin_i meant
i/sine, the reciprocal. So my symbols were better.
I didn't like f(x)--that looked
to me like f times x. I also didn't like dy/dx--you have a tendency to cancel
the d's--so I made a different sign, something like an & sign. For
logarithms it was a big L extended to the right, with the thing you take the
log of inside, and so on.
I thought my symbols were just
as good, if not better, than the regular symbols--it doesn't make any
difference what symbols you use--but I discovered later that it does make
a difference. Once when I was explaining something to another kid in high
school, without thinking I started to make these symbols, and he said,
"What the hell are those?" I realized then that if I'm going to talk
to anybody else, I'll have to use the standard symbols, so I eventually gave up
my own symbols.
I had also invented a set of
symbols for the typewriter, like FORTRAN has to do, so I could type equations.
I also fixed typewriters, with paper clips and rubber bands (the rubber bands
didn't break
down like they do here in Los Angeles), hut I wasn't a
professional repairman; I'd just fix them so they would work. But the whole
problem of discovering what was the matter, and figuring out what you have to
do to fix it--that was interesting to me, like a puzzle.
