Animals, plants, habitats

Biology

In murky waters - bioindication

How do we actually know how healthy a body of water is? Researchers use biological diversity as a criterion for water quality, among other things. Based on the…

3D-Shadows

Shadows gain depth. Illuminated with red and green light, a tetrahedron casts a red and a green shadow on the screen. Viewed through glasses with red and…

Additive Color Mixing

Mixing light colors. Play with red, green, and blue light, and with their brightness. When overlapped and adjusted optimally, red, green, and blue produce…

After Image

Seeing the void. A powerful flash of light triggers a photochemical process on our retina. This process lasts longer than the brief light flash that…

Alike and unalike

The illusion of inequality. Two identical wooden arcs lie side by side. The inner one appears larger, but it isn’t. For circular arcs, the outer edge is…

Ambiguous Figures

Clearly ambiguous. One object, two forms: “Necker cubes” belong to the category of ambiguously perceivable objects. Perceiving spatial dimensions and depth:…

Ants

Observe the bustling activity of ants as they move through a large enclosure performing various tasks. This is made of transparent material so that visitors…

Bakterien als Künstler - Damen

Creative Microorganisms A narrow aquarium is filled with sediment from an old pond. In its various layers and under different aerobic and anaerobic…

Bakterien als Künstler - Herren

Creative Microorganisms A narrow aquarium is filled with sediment from an old pond. In its various layers and under different aerobic and anaerobic…

Banana

If you place a blue filter exactly on the yellow banana, the banana appears green - logical, isn't it? A larger blue filter that also covers the white…

Benham's Disc

Benham’s disks: seeing colors where there are none. The disks display patterns with black and white shapes. When these disks rotate, we perceive colors. When…

Blind Spot

Wasn’t there an orange? Stare at the apple with one eye and slowly bring it closer to your face. At a certain distance, the orange beside the apple seems to…

Blood Vessels of the Eye

Recognizing what we normally never see. In front of (not behind) the retina of our eye, there is a network of blood vessels. We don’t see it. Our brain…

Caught quickly

React quickly and catch the sticks! Measure your reaction time on two falling sticks: Catch them as soon as they fall. The markings show you your reaction…

Changing Sides

A wire cube rotates in front of a mirror. If you squint one eye and fix a front corner of the wire cube, you see a certain direction of rotation. If you now…

Circular Deformations

Patterns come to life. Ovals form around stationary circles. Funnels emerge, cones rise. Curved lines perform a serpentine dance. Images that, when observed…

Circular Deformations

Geometric shapes come to life. What we think we see in the shapes of spinning discs! Ovals wrapping around stationary circles. Cones wobbling in a…

Coarse or Fine

Texture and perception. One hand strokes coarse sandpaper. The other hand strokes fine sandpaper. Then both hands simultaneously stroke sandpaper with medium…

Cold Test

Four degrees – only relatively cold. Touch the metal rods, please. Yes, they’re really cold. Almost painful. How painful is this brief contact? This…

Color Contrast

How blue blue can be. Two color squares, one lighter, one darker. Are we sure? As different as we perceive them, they actually share the same color. We…

Colour Reversal

A red tree turns entirely green. Why does the tree change its color? If we fix our gaze on an image long enough, the color receptors (cones) in our eyes lose…

Coloured Shadows

Three lights for shadows in six colors. Red. Green. Blue. Three lamps illuminate the white background. On it, we see six shadows of different colors: a…

Corpuscles of the Eye

Checking the pulse! Red blood cells absorb blue light particularly well. When we look into a blue light source, we see pulsating dots. A whole network of…

Crooked Tiles

Cafe Wall Illusion: the tile deception. These parallel lines really seem tilted! The black and white squares can be arranged in stripes or offset into a…

Delayed Viewing

Acting and seeing with a time delay. Catching fish with a fishing line: normally, it’s simple enough, as the magnet on the line is easy to guide. But it gets…