The F-Word

IMDb apparently has introduced an F-rating for films.

This article is part of a commentary that has been published in Varsity, the University of Cambridge newsletter. The original can be viewed here.

The next time you scroll down looking for IMDb ratings, you might be surprised to see some of these movies embossed with an F sign. No, the IMDb is sadly not becoming more hip by slyly introducing expletives as part of its ratings. Instead, this dryly lets us know whether the film has been written, directed or stars a prominent female character. So exciting! Imagine seeing an F sign and immediately knowing you have to watch it for no other reason that it features women in a prominent role. I’m already excited!

The fact remains that there are still movies created in 2017 that fail the Bechdel test. It’s a simple criterion, introduced by Bechdel in the 1980s, to see if a film had at least two female characters who spoke to each other on a topic other than ‘men’. It’s incredible that films could fail such a bare minimum threshold. But can we fault films for following their choice of a cast? For example, most superhero flicks follow the Smurfette principle where there is only one prominent female character. The fact that this eponym is derived from The Smurfs points out to us that animations aren’t immune to this bias as well. So, IMDb supposedly would bring more awareness to this issue by introducing the new letter. Or as I like to say it: The F word.

But would you like your movies to be marked like your groceries, organic or GMO, F or no F? And isn’t this a slippery slope? Where will we draw the line? LGBT, minorities and other under-represented categories should be given an equal voice as well, shouldn’t they? One could probably write a pile of supervision essays addressing why the LGBT community are probably more under-represented than women in movies. In fact, let me introduce the Guha-Bechdel test! (Yes, I just did that.)

Any movie that has at least two female/LGBT/ethnic minority characters who speak to each other on a topic that is central to the advancement to the plot passes this test.

While the idea is certainly bold, this should not be the sole measure of diversity. Movies cater to audiences and the producers assume that most people who legally end up viewing their artistic product are straight white males. This is an issue that needs to be resolved by varying the demographics more than increasing awareness. For my part, I wouldn’t necessarily sacrifice artistic quality over an F sign in viewing a movie. But there remains the enticing possibility that it would eventually end up irking some of the bigoted folks to the point of watching F-rated movies and then bragging about it! I would like to end with a few lines as given in an interview by feminist director Holly Tarquini to The Guardian:

“I hope that the F rating will become redundant as the stories we see on screen reflect our culture, and that 50 per cent of the stories we see [will be] told by and about women.”

Till then, F is the word

Killing time and people softly…

What would happen if you put a person in a microwave?

As a way of whiling my Sunday morning, I decided to ‘solve’ this unique question on Quora. The question was: What would happen if you put a person in a microwave? Yes, Quora has its dark side, and I’m loving it! Below is the answer.

Firstly it’s a terrible logistical and ethical problem. Considering that we have pushed these aside, we need to start by assuming that the person is a large sphere of some radius a! (Yep, physicists love to approximate spheres!)

Some standard mathematical approximations (Skip to the last paragraph if only interested in the final result):

We need to find the temperature on the surface as a function of time. The human is initially at temperature T_0

Now after a few seconds, the temperature boundary conditions are:



This is because a microwave heats mainly from the inside. Unlike an oven, the microwave will first heat up the centre and this heat then diffuses throughout the rest of body. (You might have probably noticed that while heating something in the microwave. Even if the outside is at room temperature, the insides are piping!) Now both T_0 and T_1 are functions of time.

T_1, the temperature at the centre directly depends on the configurations of the microwave, while T_0 will depend on the thermal diffusion rate from the centre to the surface.

Calculating T_1 is dodgy and depends on accounting for heat loss by evaporation rates of water and then extrapolating. However, for our timescales, we can consider T_1 to be more or less constant.

Now, the thermal diffusion equation for a sphere in steady state gives us: (T being the temperature)

\nabla^2 T=0

This should give us a general solution of the form:


with r as the radial coordinate.

Thus, inspired by the steady state solution, we can write:


Thus B(r,t) can be written as r(T-T_0)

This gives us:

\frac {dB}{dt}=D \frac{\partial^2 B} {\partial r^2}

where D= \frac{\kappa}{C}

I’m composed of quite a decent proportion of laziness (about 80\%) so am skipping a few steps which mean that I would not need to type out several lines of equations in \LaTeX. It should suffice to say that here I am merely converting the thermal diffusion equation to the standard 1-D case which is easier to solve.

This gives us B(0,t)=B(a,t)=0, the 2 boundary conditions. Also  B(r,0)=r(T_1-T_0), since T=T_1 at t=0. (ie the temperature at the centre due to microwave)

And feeding back these equations back to our diffusion equation, we obtain a solution of the kind given below. The general solution will involve expanding these terms with some coefficients.

B_n=\sin (n\pi r/a) e^{-D(n\pi/a)^2 t}

B(r,t)=\Sigma_{n=1}^{\infty} A_n \sin (n\pi r/a) e^{-D(n\pi/a)^2 t}

Similarly, we can obtain the coefficients A_n. Actually it involves wrting out the expansion with A_n for t=0 and using the orthogonality condition. A_n comes to \frac {2a}{n\pi}(T_1-T_0)(-1)^{(n+1)}

Combining both A_n and B_n, we finally obtain for the surface of the human body, temperature as:

T(a,t)=T_0+\frac {2a}{\pi}(T_1-T_0)\Sigma_{n=1}^{\infty} \frac{(-1)^{(n+1)}}{n}\sin (n\pi) e^{-D(n\pi/a)^2 t}

So, now let’s plug in some values.T_0, the average body temperature is 37^{\circ}C.

D, the thermal diffusivity is given by the ratio of conductivity to specific heat capacity. (It’s actually the Heat Capacity per unit volume for pedants. But since humans are mostly water, weight and volume cancel out.) Guiltily browsing figures for human thermal conductivity and heat capacities, I jotted down some figures. Again, plugging in those values, we get D=0.543/3470=1.6\times 10^{-4}.

I estimated the average chest width, a to be 1 m from available figures.

Now putting them back:

T(1,t)= T_0+ 0.63(T_1-T_0)\Sigma_{n=1}^{\infty} \frac{(-1)^{(n+1)}}{n}\sin (n\pi ) e^{-1.6\times 10^{-4}(n\pi)^2 t}


The exponential term is extremely small. The second term only starts to matter heavily when t \approx 10^3 seconds or about 17 minutes or greater, which means that it takes at least 1/4th of an hour for the temperature at the skin to reflect significant changes. Thus, under approximations made, it should take more than 17 minutes to completely cook a human alive for temperatures sufficiently greater than 37^{\circ}C independent of configurations of the microwave.

Thus we see that the time rate to fry the human is mainly dependent on T_1 and thus the rate at which the microwave heats the centre of the human. Although other effects like surface currents due to the varying electric and magnetic field apart from an intense burning at the centre might not be a pleasant experience as well have not been considered, these could play important roles as well in the heating. Else, he would slowly be evaporated from inside out as his body is drained and heated at the same time. The human body is about 80\% water and what will be left of him in the microwave will probably be a mess best left for the morgue!


I would need to add if this wasn’t apparent already is that this is an order of magnitude estimate. Microwaves don’t really heat from the centre outwards, but it should give a reasonable enough estimate all the same. A better way to look at the problem including any further mathematical considerations that may be considered are welcome from anyone who has chanced upon this crazy article!

The Sailboat


Periwinkle brushed away the horizon from skies and oceans;

People wouldn’t be same.

Jonquil kissed Ecru with passion as the final sun bathed them in righteous flames

Without passing judgment.

Tenebrous cloaks billowed as it outlined the sail beneath which it hid;

The refuge the weak need to seek is.

The wind would, after all, direct the journey as the currents took the keel;

Because the powerful decided or despite.



Alarm bells gonged in protest;

            Winds could not be painted but its effects could brew a tempest.

Sailors hauled the broken shrouds;

            Clouds distempered the darkening sky as their spirits began to douse.

The boat, over and again, leaped;

            The captain whispered his last prayers and took the crew in a final embrace

But like Hope, it couldn’t be too loud;

            Is it in my capacity to alter course or is it all a charade until the final round?