Edison´s invention records and plays sound from a cylinder, while Berliner´s apparatus uses a disc.
A type of sugar found in mammalian milk.
The medieval bell tower of the Cathedral of Pisa is the most famous leaning tower of the world.
The warship having several rows of oars was the typical warship of the Hellenistic era.
This effective strategy was based on the fast and synchronised attack of different branches of the army.
The submarine designed by the Spanish inventor Narcís Monturiol was a pioneering work in the history of underwater navigation.
The legendary M61 class locomotives of the Hungarian State Railways were manufactured by Nohab.
The arms are moved by flexor and extensor muscles.
Bones of the lower limbs are connected to the trunk by the pelvis.
This animation demonstrates the mechanism and operation of record players.
Learn the concept of colours, numbers, letters and shapes while playing
Enzymes are protein molecules catalysing biochemical reactions. Their activity can be regulated.
Colourless, odourless liquid produced by dissolving carbon dioxide in water.
One of the oxoacids of nitrogen. A colourless compound with a pungent odour, a strong oxidant.
A crystalline allotrope of carbon which was discovered at the end of the 1980s.
A polynucleotid made up of phosphoric acid, ribose, and nucleobases (cytosine, uracil, adenine and guanine).
Solid, white substance, a constituent of vegetable oils and animal fats.
The staggered conformation of ethane is more stable than the eclipsed conformation.
Electrochemical processes in a lead-acid battery produce electric current.
The building material of the cell walls and fibres of plants.