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Learn about one of the most significant Bulgarian writers of the 20th century.
Follow the journey of wheat from the field to the dining table.
Nitrogen comprises 78% of the air and is indispensable for living organisms.
Learn how physicist found out that atoms are divisible.
In this lesson, you will learn about the characteristics of hydrogen sulphide.
Toxic compounds that cause acid rain and are utilised as industrial raw materials.
The most widely produced oxyacid that has a corrosive or passivating effect, depending on its concentration.
Some processes cool the environment, while others heat it.
An element capable of self-ignition that plays an important role in the stiffness of our bones and in biological inheritance.
The age of Earth was debated for centuries by numerous outstanding scientists from different fields.
With this lesson, you can get to know yourself and your classmates better.
For thousands of years, scientists have wondered if the events around us are determined by causality, randomness or supernatural powers.
In this lesson, you will learn about the mole, a useful predatory mammal that is often considered a pest.
Silicon is the second most abundant element on Earth. Its compounds are found in various minerals.
While most metals are grey, they are not at all unremarkable.
Corrosion is the greatest enemy of metals.