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00:00Around the world, the race to win wars and explore the universe has created some of the most incredible products ever designed.
00:09And we use them every day, unaware of their amazing origins.
00:14On incredible inventions.
00:16The drum, its use in keeping time both musically and on the battlefield.
00:24The slinky, how a simple metal spring defies the laws of physics.
00:30And the fencing sword, the deadly past of an Olympic sport.
00:36We reveal the amazing history and engineering of these incredible inventions.
01:00From the Neolithic era to the 21st century, the drum has lived up to its noisy reputation.
01:06It's been used by the ancient Chinese and Mongolian tribes, the Aztecs of Mexico and Native Americans in the plains of the United States.
01:14We've asked the drums, you've got to go back in time.
01:20Really ancient times.
01:22Africa, the hollowed out log, you know, intimidating the next tribe, the enemy or the next villager coming.
01:28The Native Americans with air drums, it's telling you, we're coming.
01:32We're coming.
01:34As one of the oldest musical instruments, a drum's basic design has remained almost the same for thousands of years.
01:42Classified as a membranophone because it consists of at least one animal hide that has been stretched and when struck by the hand or drumstick, produces a deep and loud sound.
01:52While the drum is commonly regarded as the root of all music, it can't escape its bloody past on the battlefields of history.
02:01Many kingdoms, tribes and nations have risen and fallen to the sound of a beating drum.
02:09Well, the most simple use for the drum is marking time for the regiment and beating the time of their different movements when they're doing their drill.
02:16Both in the English and the American Civil War, the drum beat was paramount.
02:20It was the most important thing.
02:22Without it, you couldn't get all of your men to present at the right time, fire at the right time.
02:27Otherwise, it would be chaos on the battlefield.
02:35Liberty has been making drums in County Durham, England since 2006, and all their drums are entirely handmade, making them unique.
02:43We build the drums up from the raw timber, so we source in the birches, the maples, mahogany's, and we build up our kits ply-by-ply.
02:55Essentially, every element is handmade.
02:58All the timber is always handled by hand.
03:00It's right to the finishing process.
03:02So, you know, a really fine instrument.
03:04The process begins with the selection of the timber to make the shell of the snare drum.
03:16Strips of plywood are measured out and precisely cut to size.
03:21These will be laminated together to form the drum shell.
03:24For the outer layer of the drum, two strips of the plywood are layered up on either side of a decorative beading strip and held in place using masking tape.
03:36Each plywood layer is coated with a special glue and carefully manipulated into place within a solid-walled mould.
03:43Each veneer gets a coat of glue by hand and then placed in the mould.
03:50Each ply, we use a specific compound of glue.
03:53And there, each leaf or veneer, we placed in the mould to make up that specific drum.
03:59So it depends on the type of design of drum, how thick, how many veneers.
04:03The mould's purpose is to apply external pressure to the plywood layers.
04:08The shell is left to dry naturally in the mould for 24 hours to ensure a good bond.
04:15Once dry, the drum is extracted from the mould and checked for any imperfections in the laminate.
04:25The edges of the drum are then precisely trimmed using a circular saw.
04:35The drum surface is then carefully sanded by hand to ensure a good smooth finish.
04:42Next, the decorative bead is masked with tape and one half of the drum is stained with a coloured lacquer.
04:54Once the lacquer is dry, the whole drum is coated with a layer of wax for protection and to give a smooth finish.
05:02When the finish is complete, the edges of the drum are beveled using a routing tool.
05:08This will form a bearing edge for attaching the drum skins later on.
05:17Next, masking tape is applied around the circumference of the drum so that it can be marked up for drilling.
05:23A template is used to mark the positions where the drum will be drilled.
05:30More masking tape is applied at each position around the drum and a template is used to mark the correct positions for drilling the holes.
05:41Holes are drilled through the drum shell at all the marked locations and then all of the external metal work is screwed on around the edges of the drum.
05:56These are used for attaching the drum heads as well as the snare wires.
06:06Next, the bottom drum head is attached to the drum using a metal hoop which is screwed onto the drum through the metal lugs.
06:13The drum head is then tightened and tuned to ensure even tension around the head using a drum key.
06:20The wire snare is attached onto the bottom head of the drum.
06:25The snare wires stay in contact with the drum head and vibrate when the drum is hit.
06:30It is this that gives a snare drum its unique snappy sound.
06:37The final step is to attach the top drum head and tune it.
06:41Now it is ready for a thorough test in the drum room.
06:44So there it is, the snare drum.
06:57From marching band to rock star, it really is an incredible invention.
07:03After the break, we explore how did a happy accident during World War II create one of America's most popular toys?
07:14The Slinky, a metal marble that still continues to amaze young and old alike.
07:28But how is this innocent toy connected to World War II?
07:31And what is the amazing science behind its strange ability to walk downstairs?
07:36The simple pre-compressed helical spring, that's a coil to you and me, is first invented by Richard James way back in the early 1940s while he's working with the US Navy.
07:47As part of the war effort, James and his team are busy building spring shock absorbers to keep delicate navigation instruments onboard warships safe and free from damage even in the heaviest of storms.
07:59The Slinky was an accidental invention, if you will.
08:02It was discovered by Richard James when he knocked over some springs.
08:06He realized the way that they walked across the floor could be possibly becoming a product.
08:11And this product basically was designed such that you could play with it.
08:15He showed it to the local kids, the children there loved it, and he realized he was on to a winner.
08:19With the excitement of his invention still fresh in his mind, James and his wife borrow $500 and spend the next year researching and developing the idea so it's ready for the 1945 Christmas rush.
08:31At first, the big department stores are skeptical, so James takes initiative by demonstrating his creation to shoppers.
08:38And by the end of the year, the Slinky is the must-have toy all across the USA.
08:43The Slinky's form may be simple, but don't underestimate the complicated scientific principles at play.
08:52Nudge the coiled spring down a flight of stairs and be prepared for a major physics lesson.
08:58With a life of its own, the toy begins to move by independently falling over itself from one step to the next in a fluid movement.
09:06The Slinky is demonstrating a number of forces as it moves down the steps.
09:11Friction, inertia, momentum, and potential and kinetic energy are all acting on that coiled spring.
09:18At rest, the Slinky is still and does not move.
09:22This is called inertia and is the resistance of any physical object to change its stage of motion or rest.
09:27Inertia is aided by the effects of friction, a force that resists the movement of objects as they slide against one another.
09:37In the Slinky's case, the air that passes through it and the carpet that covers the steps.
09:42The fact that the Slinky is at the top of the stairs means the effects of gravity are stored as potential energy as spring tension.
09:50If this energy is released, the potential energy is converted to kinetic energy.
09:57The form of energy governed by motion, which means the Slinky is now moving.
10:02So why does the Slinky keep going?
10:05Well, as the Slinky takes its dive down the first step, it stretches, thereby storing energy.
10:11That energy reaches a point where it must pull the tail along, flipping it over to the next step.
10:16Now momentum comes into play.
10:20This flipping action continues as the Slinky's momentum cannot be stopped by the forces acting against it.
10:25For example, the friction.
10:27Objects with a larger momentum require more energy to move and to stop, while those with low mass and velocity have less momentum.
10:35Thus, the greater the weight of the Slinky and the downward angle in which it is traveling, the greater the momentum.
10:41Which is why a metal Slinky is better at traveling downstairs than a plastic one.
10:45This complicated but playful action has captivated children ever since it was first introduced over 70 years ago.
10:52And its popularity shows no signs of declining.
10:56Enough Slinkies have been sold to go around the earth a staggering 121 times.
11:01That's over 300 million individual items.
11:05They've gone to space on the shuttle and been used by US troops in Vietnam as portable radio antenna.
11:10It seems there's no stopping the excitement of the old toy.
11:18The Slinky, truly an incredible invention.
11:22Coming up, a special slow motion experiment that reveals just how the Slinky actually works.
11:28The Slinky might have been flying, should that be floating, off the shelves since the 1940s.
11:49But can it actually fly, or more correctly, float?
11:51Let's try and find out.
11:54The experiment.
11:55We will drop a large Slinky from a great height and film it using a special slow motion camera to capture the results.
12:02To start, a large building with easy window access to allow for very scientific dropping of classic children's toy.
12:09Check.
12:11Large Slinky.
12:12Check.
12:13Special slow motion camera focused and exposed at the absolute perfect settings to capture our spectacular Slinky fall.
12:20Check.
12:21Our fearless tester ascends the stairs, takes position, and is all set for the experiment to begin.
12:27With his arms stretched out at a perfect 90 degrees to his body, he lets the Slinky unravel to its fullest extent while expertly holding on to one end.
12:36He signals that he is ready, and a disembodied hand presses record on the camera.
12:40The test can begin.
12:43Our man lets go of the Slinky, and less than two seconds later, it hits the ground.
12:48Did you see the Slinky float?
12:50No?
12:51Neither did we.
12:52Let's review the tape.
12:56Now, seen at 150 frames per second, we can see something amazing happen.
13:01As the Slinky is released, the top of the toy falls vertically as you would expect.
13:05But, look at the bottom, it's not moving.
13:08Astonished?
13:09Well, we are.
13:11But how is this steel spring cheating gravity?
13:14Again, science comes to our aid.
13:16Before it is dropped, the bottom of the Slinky is suspended, with gravity pulling it down in one direction, and the spring's tension pulling it up in the other.
13:24So equal and opposite forces act on the bottom, leaving it motionless.
13:29When the top is released, the information that the tension has changed takes a moment to reach the bottom of the spring.
13:35Once the wave hits the bottom of the Slinky, it knows to fall to the bottom, so to speak.
13:42So there you have it. Point proved.
13:45The Slinky can float.
13:46Well, sort of.
13:48As we said before, the Slinky really is an incredible invention.
13:52Fencing is a sport of precision, style, and grace.
13:58Watching two world-class fencers on the Olympic stage is something to behold.
14:01However, it is a world away from the dark history of dueling that was the predecessor of the sport.
14:09Beginning with prehistoric clubs and spears, armed combat has been around almost as long as mankind.
14:16Throughout history, there are plenty of references to duels.
14:20We've all heard about Roman gladiators, but it is perhaps a lesser-known fact that Romans frequenting baths often dueled with sticks,
14:28an early sign of what was to evolve into modern fencing.
14:31Dueling is the engagement in combat between two individuals, both with matching weapons and often with a set of pre-agreed rules.
14:39Duels are fought as a way of regaining or retaining a sense of honor, as opposed to necessarily killing the opponent.
14:45Roman soldiers are trained to thrust instead of cut, as a raised arm cutting motion would expose vital organs to the enemy.
14:52This thrust is the basis of modern fencing technique.
14:55By the 14th century, sword fighting schools are common in many European countries.
14:59These establish a correct way to fight with a sword, and the inability to do so is seen as ungentlemanly.
15:07It was a fencing instructor called George de Silva who actually said that if a man carries a sword but cannot use it,
15:15he's as full ridiculous as a man who carries books but cannot read.
15:18By the 19th century, as duels become less common and actively discouraged, fencing is increasingly recognized as a sport.
15:27Slowly, the combative aspect of fencing fades until we are left with the pure sport of today.
15:33It becomes an Olympic sport in 1896.
15:36After the break, we get straight to the point and see how a modern fencing sword is crafted.
15:40Modern Olympic standard fencing is broken into three categories, each referring to the weapon used, and each with their own differing set of rules.
15:59Foil fencing uses a light and flexible sword. Arms and legs aren't allowed to be targeted, so all of the action takes place with accurate thrust to the torso, neck, and groin.
16:10Ape is similar, but the sword is heavier, and the whole body can be targeted.
16:15Sabre fencing only allows athletes to target above the waist, and uses a light, cutting sabre sword.
16:19Today, because of the high-speed nature of the sport, and to ensure accuracy, all judging is done electronically.
16:27One of the leading producers of modern Olympic fencing equipment is London-based Leon Paul.
16:32So we've been producing fencing equipment for 96 years, but we've been creating swords and forging the blades for about 60 years now.
16:40So how are these incredible inventions actually made?
16:43There are many individual processes involved in producing an Olympic standard fencing sword.
16:50It begins with miraging steel, a metal of superior strength and toughness, yet that has a high level of malleability.
16:58We use miraging steel for the Olympic blades, and that's because it has very little carbon in them.
17:04That means less floors are likely to propagate, and that means that it's going to last a very long period of time.
17:09The steel is first cut to the correct length using a saw.
17:13This particular automated saw can cut many blades at a time to precisely the right measurements needed.
17:19Once cut, the area of the blade that will form the handle is then heated to form what is known as the tang.
17:26These tangs are rounded and allow for comfortable grip for the addition of a molded or wooden handle.
17:30The blade is then taken to the main forge, where it is heated to approximately 1500 degrees Fahrenheit using radio frequency coils, much like the heating process in a microwave.
17:43Once the metal is red hot, rows and rows of very strong hammers thin the blade out to the correct proportions to produce the perfect foil shape.
17:50Now formed, the blade is beginning to resemble a recognizable foil.
17:56The metal is then heat treated. This is vital to producing a great quality blade.
18:01Because the steel can become brittle in the forging process, heat treating re-strengthens the metal and also increases its flexibility and longevity.
18:10The world record for the longest lifespan of a blade is about 37,000 cycles.
18:23That's 37,000 hits and that record is actually held by a Leon Paul blade.
18:28The surface of the blade is then finished, first in a grinding machine which gives it a smooth finish.
18:32Now the blade continues through the shot preening process. This fires small beads of glass at the steel that create a composite residual stress layer, in addition to increasing its sheen.
18:51The blade is taken to be laser engraved with a Leon Paul stamp, showing when and where it was made, as well as the grade of steel.
18:58A wire that connects the electronic tip of the blade to the sensor is fitted with glue, completing the blade making process.
19:14It is now time to create the guard of the sword.
19:17This is made from an aluminum sheet, which is bent to shape using the hydraulic press, which forms the perfect rounded shape for protecting the hand of the user.
19:25It is then riveted in order to reinforce the base, before being stamped with the Leon Paul logo.
19:32The base is then polished by running water over the metal, scrubbing it with china, and finishing it off under the polishing wheel.
19:41Now that we have a finished blade and guard to match, it all needs to be assembled into a full sword.
19:48The electronic wire is attached to the electronic socket, meaning the sword is now equipped to score electronically.
19:56This is fitted along with a cushion pad and handle.
19:59The handle can be custom made using a 3D printer, or be fitted with a more traditional wooden handle that has been hand wrapped in leather.
20:07The sword is then tested to ensure it conforms with all the official regulations.
20:11The fencing sword, certainly an incredible invention.
20:19So there you have it, a glance through the hidden history and super science of some amazing products we use every day.
20:27The drum, the slinky, and the fencing sword.
20:31They may seem common and ordinary, however these products help change the world one incredible invention at a time.