Science Flashcards
When was the Big Bang?
The Universe came into existence as a “singularity” about 13.7 billion years ago, in an event that has been characterized as the big bang. In the first fractions of a second, the universe expanded rapidly and the forces and particles of physics were created. That expansion still continues.
Who was Albert Einstein?
Einstein’s theories changed our understanding of the universe in which we lived. A victim of persecution, he believed passionately in the value of learning. He was ad remains the popular conception of scientific genius.
What is light?
Light is composed of elementary particles– called photons, packets, or quanta– of energy that make up all forms of electromagnetic radiation. Photons have no mass and no charge, but they have energy and momentum. They are governed bu quantum mechanics and show properties of both waves and particles.
Where is the limit of the universe?
The concept of a boundary to the universe is meaningless, as there is nothing outside the universe, but the width of expanding universe could be as much as 156 billion light-years. The universe isn’t infinite… yet
Why are time and space the same thing?
Space and time can be considered as aspects if a combined space- time continuum. The idea was put forward by Hermann Minkowski but is implicit in Einstein’s theories of relativity.
What is Alchemy?
Alchemy as both a mystical philosophy and a practical art had its origins in ancient Egypt. The goal of the alchemist was to turn base metal into gold and discover the key to immortality. In both the Islamic world and Europe, alchemy became increasingly scientific, ultimately developing into chemistry.
Who was Marie Curie?
Marie Curie (1865-1934) was born Maria Sklodowska in what is now Poland. She overcame considerable financial difficulties and male prejudice to become one of Europe’s leading scientists, and is most famous for her discovery of the intensely radioactive element radium.
Where do diamonds come from?
Diamonds are made of pure carbon. They are formed deep in Earth’s crust under heat and pressure. The diamonds that are being mined now– chiefly in South Africa and Australia– were created between one and three billion years ago.
When does a solid become a liquid?
A solid becomes a liquid when it reaches melting point. At that temperature, with the input of the substance’s latent heat of fusion, the movement of the molecules becomes sufficient to overcome some of the attraction between the molecules, the rigid structure of the solid breaks down, and the substance becomes liquid.
Why is water a solvent?
Water is a solvent– and a very good one– because its molecules are polar. This means that they have positive and negative regions, enabling them to bond with other polar chemicals and with compounds whose molecules have ionic bonds(bonds between positively and negatively charged atoms). Water molecules also bond with each other.
When did the dinosaurs die out?
The dinosaurs died out about 65 million years ago, over a period of a few thousand years which is a short time in biological terms. The most likely reason for their disappearance is that the impact of a very large meteorite `affected the climate and the atmosphere, reducing the food supply. In the competition for the dwindling resources, the dinosaurs lost out to mammals, birds, insects, and other reptiles.
Who was Carl Linnaeus?
Carl Linnaeus (1707-1778) was a Swedish biologist whose studies of plants, animals, and humans led him to develop the first comprehensive system for classifying living things, based on shared physical characteristics. “Linnaean taxonomy” is the basis of the system that we use today, which gives every species a unique Latin name and places it in its evolutionary relationship with other species. Linnaeus is also one of the founders of ecology.
Why is evolution controversial?
Evolution remains controversial for various religious groups that insist upon literal interpretation of certain divine creation stories. Many are also unwilling to accept that, rather than being the pinnacle of created order, humankind is merely the temporary outcome of an undirected process.
What is DNA?
DNA, or deoxyribonucleic acid, is a complex molecule found in almost all living cells. Its structure is a double helix – two spirals bound together by four chemical compounds that link in pairs. The sequence of these compounds along the spiral acts as a code to carry information that enables the cell to assemble amino acid into proteins. In this way DNA directs the growth and function of cells.
Where do Homo Sapiens come from?
Homo sapiens meaning “man of wisdom” is the Latin name given to modern humans by Carl Linnaeus. The branches of the family tree that lead us to separate from the gorillas’ branch some 8 million years ago, from the chimpanzee some 5 million years ago, from the Australopithecines 2.5 million years ago, and from the Neanderthals about 300,000 years ago.
