amateur: One who engages in a pursuit as a pastime, not as a profession.
atmosphere: The envelope of gases surrounding Earth, another planet or a moon.
chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.
chemical reaction: A process that involves the rearrangement of the molecules or structure of a substance, as opposed to a change in physical form (as from a solid to a gas).
chemistry: The field of science that deals with the composition, structure and properties of substances and how they interact. Scientists use this knowledge to study unfamiliar substances, to reproduce large quantities of useful substances or to design and create new and useful substances. (about compounds) Chemistry also is used as a term to refer to the recipe of a compound, the way it’s produced or some of its properties. People who work in this field are known as chemists.
concentration: (in chemistry) A measurement of how much of one substance has been dissolved into another.
electric field: A region around a charged particle or object within which a force would be exerted on other charged particles or objects.
factor: Something that plays a role in a particular condition or event; a contributor.
force: Some outside influence that can change the motion of an object, hold objects close to one another, or produce motion or stress in a stationary object.
metal: Something that conducts electricity well, tends to be shiny (reflective) and is malleable (meaning it can be reshaped with heat and not too much force or pressure).
meteor: (adj. meteoritic) A lump of rock or metal from space that hits Earth’s atmosphere. In space it is known as a meteoroid. When you see it in the sky it is a meteor. And when it hits the ground it is called a meteorite.
molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).
oxygen: A gas that makes up about 21 percent of Earth’s atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).
ozone: A colorless gas made of molecules that contain three oxygen atoms. It can form high in the atmosphere or at ground level. When it forms at Earth’s surface, ozone is a pollutant that irritates eyes and lungs. It is also a major ingredient of smog.
ozone layer: A layer in Earth’s stratosphere. It contains a lot of ozone (a molecule made from three oxygen atoms), which helps block much of the sun’s biologically damaging ultraviolet radiation.
persistent: An adjective for something that is long-lasting.
physics: The scientific study of the nature and properties of matter and energy. Classical physics is an explanation of the nature and properties of matter and energy that relies on descriptions such as Newton’s laws of motion. Quantum physics, a field of study that emerged later, is a more accurate way of explaining the motions and behavior of matter. A scientist who works in such areas is known as a physicist.
satellite: A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space.
star: The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become hot enough, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
survey: To view, examine, measure or evaluate something, often land or broad aspects of a landscape.