00:00 What is hidden inside the Coca-Cola cans and the usual household batteries?
00:05 Why do magnets affect breakfast cereals?
00:09 Do pedestrian crossing buttons really work?
00:12 Or are they just useless decorations?
00:14 What does this USB symbol really mean?
00:17 I'm not sure I know the answers to these questions and similar ones,
00:22 but I can't wait to learn the truth with you.
00:24 Let's find out together.
00:26 Coca-Cola cans have a secret that few people know.
00:30 Here is a Coca-Cola can.
00:32 Let's plunge it into a highly corrosive alkaline solution.
00:35 Aluminum dissolves due to a process known as hydrolysis.
00:40 And we can see a plastic coating inside the can.
00:43 It is made from a polymer or epoxy resin
00:46 and serves as a kind of protective barrier between the aluminum walls of the can and the rather acidic soda.
00:53 Despite a popular myth, household batteries do not actually contain liquids.
00:58 And if you cut them accidentally, no toxic liquid will spill over.
01:03 Most of them are dry batteries, made of electrochemical cells.
01:07 They transform chemical energy into electrical energy.
01:10 Larger batteries often contain many small cells in their body.
01:15 Even Tesla vehicles' batteries are made up of several small cells.
01:19 Once combined, they easily provide the necessary voltage.
01:23 Most toothbrushes have hairs of different colors.
01:29 But they are not only pleasant to the eye.
01:32 These hairs, often blue, have a specific function.
01:36 They are called toothbrush indicators,
01:39 and their color fades as you use the brush.
01:43 The American Tooth Association recommends changing your toothbrush at least four times a year.
01:48 And by becoming more pale, these hairs help you determine when it is time to replace your toothbrush.
01:54 You will probably agree that there is no better snack than a packet of chips.
01:59 Some are flat, others have holes.
02:02 Is it just a matter of aesthetics?
02:04 Not really.
02:06 The main goal of these lines on certain types of chips is to help distribute spices and seasonings.
02:12 In other words, all these substances that give your chips a cheese flavor are mainly stored inside the lines.
02:20 In addition, the lines make the chips more crispy.
02:24 Now, this may be a surprise.
02:28 But some cereals for breakfast are magnetic.
02:31 It is because they are often enriched in iron in the form of fine powder.
02:35 Because of this addition, the cereal flakes are attracted by the magnets.
02:40 All this may seem a little scary.
02:42 But in reality, the amount of iron in the flakes is minimal and does not pose any danger to your health.
02:48 This clear liquid in gel pens is called an ink follower or blocking fluid.
02:54 The gel in these pens contains pigment particles dissolved in a polymer solution.
03:00 The main task of the blocking fluid is to serve as a barrier to prevent the gel from evaporating or fleeing.
03:07 Without this transparent fluid, your gel pen would not work.
03:11 The fluid always stays in one position and does not dissolve with the gel.
03:16 It does not retreat either, nor does it flow out of the pen.
03:20 Many pedestrian crossing buttons, especially in New York, are placebo buttons.
03:26 They do literally nothing when you press them.
03:29 Originally, they were functional after being introduced in 1964.
03:34 But today, most of them do not affect traffic lights, which are programmed according to the real needs of the traffic flow.
03:43 Why do such buttons exist then?
03:46 It is a simple psychological trick that gives you an illusion of control.
03:51 You may have noticed that the seats in the cinemas are almost always red.
03:57 This choice is not a fortuitous one.
03:59 It has a strategic importance that is rooted in visual science.
04:03 Indeed, red light has a longer wavelength.
04:07 This means that it is the first color to disappear in low light.
04:11 This allows the audience to focus better on the screen once the film has started.
04:16 Such a design choice improves the viewing experience by minimizing distractions.
04:22 Do-Dans are essential for pedestrian safety.
04:27 But at the same time, they can seriously increase car emissions due to the constant acceleration and deceleration they cause.
04:35 To solve this problem, some cities, like London, test fictitious do-dans.
04:40 These are illusions of optics painted on the road.
04:43 They seem to be elevated from the driver's point of view, but in reality, they are flat.
04:48 Authorities hope that this approach will slow down drivers without having a negative impact on the environment.
04:56 Soda bottles are always filled in such a way that there is a space between the liquid and the cap.
05:02 This is because soda contains carbon dioxide.
05:05 It is a gas that can expand once a bottle is heated.
05:09 If there is no vacuum in the bottle, it can break due to the pressure that accumulates inside.
05:14 In addition, when you open your drink, the gases come out in the form of bubbles, overflowing the drink.
05:20 The empty space also helps to solve this problem.
05:25 The USB symbol, which looks like a trident, has always aroused multiple speculations about its origin.
05:31 A popular idea is that it represents Neptune's trident and symbolizes power and adaptability.
05:37 But there is also a slightly less exciting theory.
05:40 A man who claimed to have designed the symbol in the 1980s, declared that it was supposed to represent connectivity.
05:47 The large circle symbolizes a computer, while the attached shapes, the circle, the triangle and the square represent different outputs.
05:55 The design of a tennis racket has a specific feature known as the "throat".
06:03 It is an open space under the racket head.
06:06 This space is not only intended to store the balls.
06:09 It also improves the aerodynamics of the racket by letting the air pass through.
06:14 It considerably reduces drag during swings.
06:17 Speaking of tennis, tennis courts are generally built with a north-south orientation.
06:23 This helps to minimize the impact of the sun's position during the game, ensuring that no player has the sun directly in their eyes.
06:30 Look closely at the airlines of a tramway, and you will see that its contact points make zigzags rather than go in a straight line.
06:40 This is because all trams have pantographs attached to their roofs.
06:44 The upper part of the pantograph is gradually worn by the airline and must finally be replaced.
06:51 To use it uniformly, the wire is not strictly installed along the path of the tram, but in a zigzag pattern.
06:58 As the tram moves forward, the pantograph slides along the wire, and it sews uniformly.
07:07 These water fountain cones are intentionally designed to prevent users from placing them.
07:14 This allows employees to minimize the risk of spilling water on their desks around various electronic devices.
07:21 In addition, less material is used to produce cone-shaped cones, which makes the process less wasteful and more profitable.
07:29 It also promotes durability by encouraging people to drink their water quickly and get rid of their cup immediately afterwards.
07:37 Most suitcases have two zippers, and they are used for several things.
07:44 First of all, if a zipper breaks down, the other can keep the suitcase closed.
07:49 Even better, having two zippers allows you to access small sections of your suitcase more easily without having to open it completely.
07:57 And finally, when you have two zippers, you can connect them with a lock to reinforce security.
08:04 Some plastic milk containers have bumps on their sides. These bumps serve several purposes.
08:12 When the milk spills, it usually causes a swelling and high pressure accumulation inside the container.
08:18 This is when the bump unfolds and prevents the container from exploding.
08:22 In addition, if you decide to freeze the milk, it will spread like any other liquid.
08:27 And again, the indentation will unfold and prevent the container from breaking inside your freezer.
08:33 If you have ever wondered why fake bags exist, you must hear this.
08:39 The main reason is that if a garment has a cut or a specific shape, the bags can spoil it.
08:45 They can modify the shape of the item, either in the warehouse or already on the sales portal in detail.
08:50 The solution? Get rid of the bags in the key areas.
08:53 In addition, fake bags are obviously cheaper and they don't deform.
08:58 Thermos was not invented to keep your coffee hot.
09:03 It was created by a Scottish scientist who simply wanted a safe place to keep his chemical products at a stable temperature.
09:10 So he took two bottles, placed the smallest inside the largest, and sucked the air between them.
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