BEAUTIFUL EXPERIMENTS: THE WAY THINGS REALLY MOVE

I have never been a fun of non-fictional books but as the years have gone by I found myself picking up more books that fall under this category and finding them an enjoyable read. Most of these books were read on recommendation, and some were read for reasons I have previously explained. One such great reads was "The Ten Most Beautiful Experiments" by George Johnson, describing experiments that discovered what we may now consider basic science. Some of the experiments described were new to me, all the experiments were indeed beautiful and I couldn't help but acknowledge the intricate and delicate designs of these experiments. So here is my take on one such experiment by Galileo Galilei (yes that is really his last name) as described by George Johnson in the chapter "The way things really move".

A genius collection of geniuses at work

THE MAN

The first born in a family of 6 and another great scientist who acknowledged the co-existing truth in both scientific literature and biblical scripture, Galileo is sometimes referred to as 'The father of modern science' and for good reason. Before his death in 1642 his contributions to science passed him off as a physicist, astronomer, mathematician and philosopher. Some of his notable contributions include discovering the four largest satellites of Jupiter, building an early stage thermometer and the observation of sunspots (presumably using his improved telescope designs). In addition to his great scientific achievements, he was also an accomplished musician, a talent that will later prove useful. However long before he started studying stars and getting into trouble for promoting the idea of a heliocentrism, he was studying the movement of objects. This is where his contribution to 'Beautiful experiments' is drawn from. 

THE PROBLEM

Aristotle had previously proposed that an object falls in relation to its weight, that is to say, the heavier an object, the faster it falls. As sensible as this sounds anyone who paid attention in science class remembers that this is wrong even if the details are a bit fuzzy. For example, if you drop a 100 pound cannon ball and a 1 pound musket ball, even though the cannon ball weighs a 100 times as much as the musket ball, it does not fall a 100 times as fast. Actually, the timing between the two objects hitting the ground is pretty close and Galileo made note of this, arguing that factors such as wind resistance need to be considered. 

We all appreciate that any object will increase in speed as it falls but this also raises a bunch of questions; Do objects of different weights equally increase in speed as they fall? Does the speed increase all at the beginning or continuously until it lands? How about a huge burst half way down?. Although these are all genuine questions that drove Galileo, the real question is how can this be tested?. 

Really now?

How do you measure the speed of a falling object if you found yourself in the year 1604 with no time lapse videos, stopwatches, Wikipedia or whatever modern technology was involved in your idea? Galileo set about to answer these questions armed with nothing more than a bronze ball, a fancy plank, ''apparently'' a water clock (like an hour glass filled with water) and his musical skills, the most important attribute during this experiment.

THE SOLUTION AND BEAUTY

The experiment in question here is discussed in one of his written pieces, 'Discourses concerning two new sciences'. Galileo describes propping a 20ft long, 10in wide board at an angle and creating a smooth groove on the inside. A smooth bronze ball was then placed at the top of the groove and the time required to roll down from one end to the next was noted. After this the time required to roll various lengths (quarter, half, two-thirds, and so on) of the board was also recorded.

Now the speed an object travels is calculated as the 'distance' covered divided by the 'time' it took to cover this distance. So here we know the length of the board  which is the distance the bronze ball would have travelled, but how did he calculate the time? Apparently, according to Galileo, this was done using a water clock. In this experiment, it was not important to measure time in terms of seconds and minutes. The most important thing was that the measure of time had to be constant (for example a beat or rhythm will work just fine). So for arguments sake lets just assume every drop of water from his water clock is the same as half a second. What he then did was scratch a tick on the board to show how far the ball had travelled with every drop of water (apparently). He then recorded the distance travelled by the time the ball reached each tick and recorded numbers that look just like this;  

Feel free to try and identify the trend in how distances between ticks increases

With his little set-up, he showed two things:

• Firstly, the distance between ticks made on the board increased as the ball rolled down. So the distance between ticks 2 and 3 will be greater than the distance between ticks 1 and 2. Surely we will expect this because we know the ball gains speed as it rolls down. 

• Secondly there was a rule which could predict how much this distance increased between every pair of ticks. So once you know the distance travelled between ticks 1 and 2, you will be able to predict the distance that will be travelled between ticks 2 and 3. This rule did not change even when the angle of the propped up board was increased or decreased, so you will expect it to also be true if the ball fell straight down rather than roll.Basically he explained how gravity increases the speed of a falling object.

So what was the rule that predicted how an object gained speed when falling? Its known as the times-squared law. Rather than explain, you can have a look at his original results with some added notes;

Aaaaaah now you see it.....

As ingenious as his measurements with the water clock may be, many scientist that studied his work after his death believed him to be fibbing (hence my constant use of the word 'apparently'). Technically such an experiment works, but it can have so many errors that it only really works with hindsight when you know what you are doing and looking for. So how did Galileo really measure times as small as half a second? Well if you remember, all he needed to do was find a way to divide time into equal portions, something that will come naturally to any good musician. Yes, Galileo's talent on the lute will have been the secret to his accurate time measurements. Even non-musicians can notice when the timing of a beat is off. It's like we all have this intrinsic clock which helps us to appreciate or criticise an orchestra, do the two-step or dance on time to a salsa beat. 

THE LEGACY

One such scientist named Stillman Drake - 'Y.O.L.O' - repeated Galileo's experiments using the song 'Onward Christian soldiers' to establish a rhythm at two-beats a second and mark off his own measurements. Amazingly after a few tries it produced results similar to Galileo's, proving that  this was a viable way to conduct the experiment without a stopwatch or water clock. 

So if this was the initial method used to discover the times-squared law, why did Galileo not just say so? Well understandably, even now it will be considered silly to say to the world's leading scientists that "I tested this law by singing a song while a ball was rolling down a plane and it proved quite exact". Nonetheless, thanks to Galileo, the world of abstract mathematics was related to real life physical properties of motion. Thanks to Galileo we now know that all other things been equal, the speed at which an object falls is independent of its weight.

For all his efforts he has a few moons named after him, became a household name and even has the European global navigation satellite system named after him. Not bad for a man who spent the last years of his life under house arrest. 

BEAUTIFUL EXPERIMENTS: MEASURING THE IMMEASURABLE

I have never been a fun of non-fictional books but as the years have gone by I found myself picking up more books that fall under this category and finding them an enjoyable read. Most of these books were read on recommendation, and some were read for reasons I have previously explained. One such great reads was "The Ten Most Beautiful Experiments" by George Johnson, describing experiments that discovered what we may now consider basic science. Some of the experiments described were new to me, all the experiments were indeed beautiful and I couldn't help but acknowledge the intricate and delicate designs of these experiments. So here is my take on one such experiment; Ivan Pavlov's conditioning experiments described by George Johnson in the chapter "Measuring the immeasurable".

A genius collection of geniuses at work

THE MAN

The son of a Russian priest, Pavlov was headed down the same path until he discovered the writings of Darwin amongst others. He soon went to study under Mendeleyev (The guy who gave us the periodic table) in Saint Petersburg and about 20 years later he became head of physiology at the Institute of Experimental Medicine. Pavlov worked with his pet/lab dogs who were really personal to him, with names such as Spot, Weasel, Old russian prince and Genghis Khan. He discovered that salivation and gastric juices contained enzymes which were specifically secreted dependent on the food to be digested and this work on the digestive system won him a Nobel prize in 1904. This was when he switched into the study of the nervous system because apparently the field was lacking strong players and who better to recruit than a Nobel prize laureate. Whoever thought winning the Nobel prize was the peak of a scientist career obviously never heard of Pavlov because this is where his true contribution to science begins.

THE PROBLEM

During his 'digestive system' experiments, Pavlov noticed what any dog owner will undoubtedly know; it is not just the food that caused the animals to salivate. Overtime just the sight of the food bowl, the opening of the cupboard at feeding or pretty much anything that consistently happened before feeding was enough to make his dogs salivate. Not knowing what else to make of this, he named them 'Psychic secretions'. Unlike the natural 'unconditional' salivation that occurred when the food was presented to a dogs, these 'Psychic secretions' were learned through life. His dogs will salivate more in anticipation of food or stop salivating if you kept teasing them with food. This whole idea of psychic secretions were 'conditional'. It is all well and good noticing this, but how do you prove for a fact that a supposedly innate instinct of the dog could be controlled by a man. Switched on and off, turned around, diminished and enhanced like some dimmer switch. At the time, this work was neccessary to bridge the gap between the physical world and the mental world.  

THE SOLUTION AND BEAUTY

The solution is quite simple really; set up a series of experiments to show that you can make your dogs salivate to anything of your choosing. Pavlov moved all his dogs to a specially built unit where he had as much control as possible over everything the dogs were exposed to. This included the sights, sounds, smells and even vibrations from nearby buildings. Strict timetables were maintained for everything and all dog-man interactions were also controlled. At the time, many may have considered the steps taken to be a bit over the top but what he showed by these experiments was nothing short of beautiful. He could make his dogs salivate to the most random things such as the ticking of a metronome, a light flash, the sound of a horn, specific musical notes and even the rotation of an object (this could be further specified; clockwise or counter-clockwise). The only conditions to pull off these experiments were consistency in terms of context and a close timing between the 'unconditional' stimulus (random stimulus of your choosing) and  the meat (conditional stimulus).  

THE LEGACY

Nowadays experiments that try to investigate animal behaviour use some kind of test based on Pavlovian conditioning. His work has come so far that these experiments are used to test various things such as memory, tinnitus, hearing impairments, genetic mutations and vision. Basically if you need an animal to answer 'Yes' or 'No' to pretty much any question of scientific interest, Pavlovian conditioning is the way to go.

Pavlov's work will forever be remembered and in recognition of the dogs that contributed to this most beautiful experiment, 'Monument to a dog' was set up at the Institute.

(Photo by Sergey Grachev)