Nature, despite its diversity, has features that connect it. In order to see these common threads, we have combined the exhibits in the Experimental Zone into nineteen thematic groups. In this way, the same phenomenon can be explored in many contexts.
With this hypnotic exhibit, you can see how an image is created in a flat mirror.
The exhibit consists of many small, round and flat mirrors placed inside a fragment of a wooden sphere. The mirrors, which form a spherical arrangement, are directed at one specific point located in front of the exhibit.
If you place your eye at this point, you will see a reflection of it in all 285 mirrors. Why? Your eye is at the intersection of the straight lines passing through the centre of each mirror, parallel to their surfaces. As a result, light travelling from your eye falls perpendicular to the mirrors and then reflects off them and goes back to your pupil. This lets you see your eye in each mirror.
The exhibit is part of the Symmetry group.
This is one of our visitors’ favourite exhibits. It uses high-speed photography, which allows for freezing movement in a split second, for example, to capture the image of a falling drop of water.
The drop begins to fall the moment you press the button, which automatically triggers the camera shutter. Using the dial, you can adjust the shutter speed. The captured image will be displayed on the television screen.
Thanks to the exhibit, you can capture a falling drop of water in different phases of motion and observe how its shape changes in subsequent captures. If you place your face right by the glass in front of the lens, with the right shutter setting, you will get a photograph in which you will see a reduced and inverted reflection of your face in the drop of water, just like in a lens.
The exhibit is part of the Eye, Image in the Eye group.
This exhibit will show you that we all glow in infrared. Just like an ordinary camera captures visible light, an infrared camera captures thermal radiation, that is, infrared light invisible to the naked eye.
On the TV screen, the visitor observes the amount of infrared radiation emitted by individual parts of their body. The stronger the thermal radiation, the lighter that body part will be.
The accessories added to the exhibit (e.g. stencils for making "thermal tattoos” or special screens) allow you to experiment with the properties of infrared and materials such as metal, plexiglass or plastic film. Thanks to this, you can observe, among others, how the image changes when you stand behind a plexiglass screen or lower your body temperature by applying a cold “tattoo”. Standing behind one of the screens, you can also check whether the material it’s made of reflects light waves or allows them to pass through. If it reflects them, it acts as a mirror and at the same time an impermeable barrier. What is interesting, the same material that is a mirror for visible light does not have to be one for infrared.
The exhibit is part of the Anatomy and Physiology group.
This surprising exhibit lets you see how your sight interprets the brightness of objects – meaning the amount of light they reflect – depending on their surroundings.
At the beginning of the experiment, the observer looks at a brightly lit plate, which appears white. When the next one is illuminated, the previous one darkens. At the end, four plates are visible, the first one appearing black. How is it possible that white became black?
Our senses do not work quantitatively (numerically), but quantitatively (by comparison). To say whether something is light or dark, black or white, our sight needs external points of reference. The exhibit shows that how we see light – and other colours as well – depends on many factors, such as the kind of lighting, the ability of the object to reflect light, as well as how our senses are functioning.
The exhibit is part of the Light and Colours group.
This very attractive exhibit, using Augmented Reality technology, develops your spatial imagination and shows what drawing hypsometric maps (reflecting the shape of the terrain) is all about.
Above a box with sand there is a camera with distance sensors and a laser projector, connected to a computer with mapping software, which reads the shape of the terrain and reflects it in the form of a colour topographic map.
The visitor can shape the terrain freely using their hands. A real-time image is projected onto the formed sand in the shape of a colour map with topographic lines indicating specific heights. The different colours indicate areas of sand at the same altitude: the highest are brown or even red (mountains), high altitudes are orange (uplands), lower ones are yellow (lower hills), low-lying areas are green (plains) and the depressions formed are blue. Additionally, the visitor can cause rainfall, holding their hands over the chosen location.
The exhibit is part of the Shapes and Patterns group.
This is a spectacular exhibit in terms of light effects about ultraviolet light. It presents the phenomenon of photoluminescence and a broad range of its applications in different areas of life, such as industry, forensics or medicine.
Various objects are placed on the table under a transparent table top. The visitor illuminates them using hand-held lamps equipped with ultraviolet-emitting diodes. Under the influence of ultraviolet light, the objects start to glow with their own light. How does this happen?
Ultraviolet light waves are invisible to the human eye. Some substances, illuminated with ultraviolet, start to glow with their own light. This is because the short ultraviolet waves, unlike the much longer visible light waves, strongly excite electrons. The excitation – the movement of electrons to another state – takes place during the transfer of energy. When the electrons return to their original state, they “give back” the excess energy by emitting light visible to the naked eye.
The exhibit is part of the Light and Optics group
This is a simple yet charming exhibit. A transparent container contains dust. With magnets at their disposal, visitors can create beautiful patterns in the container, enchanting with their fleeting nature.
The black powder particles are made of a substance that does not exhibit the characteristics of a magnet. However, when it finds itself in a magnetic field produced by another object, it shows magnetic properties.
Each particle is arranged according to the lines of the magnetic field created by the magnets, so that visitors can create patterns and spiky structures in the dust. The state of magnetisation of the particles is reversible, which is why when the magnet is moved away, the powder falls freely to the bottom of the container.
Only some metals, called ferromagnetics, show the ability of spontaneous magnetisation. The best-known ones are iron, nickel and cobalt.
The exhibit is part of the Electricity and Magnetism group.
Using metal disks, visitors can study the magnetic field between two large magnets.
These large pieces of metal are very strong permanent magnets. They are called permanent, because they create a magnetic field by themselves. The magnets in the bowl have been installed so that one of them has the north pole (N) on the end sticking out, and the other – the south pole (S). If they were not rigidly attached to the base, they would connect with each other with a great deal of force.
However, with the way they are mounted, there is a very strong magnetic field between the magnets. It is invisible, but it can be studied using ordinary steel disks, which are not magnets in themselves. Under the influence of the magnetic field, their inner structure changes and they start to behave like magnets, joining together into threads and larger groups.
The exhibit is part of the Electricity and Magnetism group.
Visitors can learn about the properties of a ferrofluid – a liquid with strong ferromagnetic properties.
This extraordinary liquid has a consistency similar to that of mayonnaise – a suspension of fat molecules in water. In this case, the suspension is made up of small needles, which can be easily magnetised, for example, magnetite particles. If we move a magnet towards them, they will arrange into unusual patterns. The liquid used here, an example of a so-called ferromagnetic fluid, was invented for the needs of space flights: in the state of weightlessness, ferromagnetic fuel can be brought to the engine using electromagnets. Today, ferromagnetic fluids are also used, among others, in the fight against cancer: a drug “trapped” in a ferromagnetic fluid can be guided using a magnetic field towards where the tumour is located, while minimising its impact on healthy tissues.
The exhibit is part of the Electricity and Magnetism group.
A small (pea-sized) ball falls from a height of about 30 cm onto a slightly concave steel surface and bounces hundreds of times. You can observe how the height and frequency of the bounces changes and discern the accompanying sound and its volume. The hypnotic bouncing of the ball is phenomenal and fascinating.
The creator of the exhibit that has enriched the new On the Move exhibition is Ned Kahn, an artist who creates works inspired by natural phenomena described by the laws of physics, geology, astronomy or chemistry.
The Chaotic Pendulum consists of several fixed steel arms in the shape of the capital letter “T”. The visitor puts the pendulum into motion and observes its unpredictable movements. This very attribute of the pendulum – unpredictability – is what makes it so fascinating. When set in motion, it will never behave in the same way. Even if you try to act with the same force, from the same position and in the same way, the effect will be completely different. The pendulum is very sensitive; even a slight change can have a major impact on its behaviour.
The exhibit is part of the Chaotic Phenomena group.
With the Light and Sound exhibit, you will get to know the differences between light and sound waves. You will see what happens to them in the air and in a vacuum.
In the air, i.e. in the state you know, you can see the light of a bulb and hear the sound of a bell every day. After the air is pumped out, i.e. in a vacuum, you can see the light, but the sound becomes inaudible. Sound waves need a medium to propagate, so there is no sound in the vacuum. Therefore, scenes from science-fiction films which feature loud explosions in space are false. There is a vacuum in space and, thus, an overwhelming silence!
This exhibit resembles a circus cannon but made out of wood. Instead of a fuse, it has a yellow knot, which you pull back like a slingshot projectile. The cannon shoots air. We pull back and let go, then we hear something strike the membrane inside the cannon, and after a few seconds, during which nothing happens, we can clearly see the air blowing on a curtain with metal tiles, several metres away. The earlier version of the exhibit had a membrane that had to be struck by hand, which led to everyone focusing on hitting it as hard as possible, instead of the phenomenon hidden in the exhibit.
As it turns out, the air that leaves the cannon has an unusual shape – it resembles a ring, a tyre or a round pretzel. This is a torus, created as a result of a whirling movement. This is the same phenomenon we observe in the case of a smoker blowing smoke rings. “Interestingly, dolphins have learned to make rings like this out of air. They blow them under water and play with them. You can see videos of this on YouTube,” explains Lech Nowicki from the Exhibition Department. Torus-shaped rings are created in nature during such events as volcano explosions, when they are formed out of smoke.
Next to a rotating metal table, you will find billiard balls, hoops, disks and rings of various sizes and thicknesses. All these accessories roll really well over a surface. How do they behave when the surface is rotating? That’s what you need to find out.