atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
bond: (in chemistry) A semi-permanent attachment between atoms — or groups of atoms — in a molecule. It’s formed by an attractive force between the participating atoms. Once bonded, the atoms will work as a unit. To separate the component atoms, energy must be supplied to the molecule as heat or some other type of radiation.
cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell. (in telecommunications) A technology that relies on a large number of base stations to relay signals. Each base station covers only a small area, which is known as a cell. Phones that rely on this system are typically referred to as cell phones.
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 bonds: Attractive forces between atoms that are strong enough to make the linked elements function as a single unit. Some of the attractive forces are weak, some are very strong. All bonds appear to link atoms through a sharing of — or an attempt to share — electrons.
electronics: Devices that are powered by electricity but whose properties are controlled by the semiconductors or other circuitry that channel or gate the movement of electric charges.
family: A taxonomic group consisting of at least one genus of organisms.
gel: A gooey or viscous material that can flow like a thick liquid.
implant: A device manufactured to replace a missing biological structure, to support a damaged biological structure, or to enhance an existing biological structure. Examples include artificial hips, knees and teeth; pacemakers; and the insulin pumps used to treat diabetes. Or some device installed surgically into an animal’s body to collect information on the individual (such as its temperature, blood pressure or activity cycle).
limb: (in physiology) An arm or leg.
liquid: A material that flows freely but keeps a constant volume, like water or oil.
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).
organic: (in chemistry) An adjective that indicates something is carbon-containing; also a term that relates to the basic chemicals that make up living organisms. (in agriculture) Farm products grown without the use of non-natural and potentially toxic chemicals, such as pesticides.
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).
polymer: A substance made from long chains of repeating groups of atoms. Manufactured polymers include nylon, polyvinyl chloride (better known as PVC) and many types of plastics. Natural polymers include rubber, silk and cellulose (found in plants and used to make paper, for example).
reactive: (in chemistry) The tendency of a substance to take part in a chemical process, known as a reaction, that leads to new chemicals or changes in existing chemicals.
robot: A machine that can sense its environment, process information and respond with specific actions. Some robots can act without any human input, while others are guided by a human.
silicon: A nonmetal, semiconducting element used in making electronic circuits. Pure silicon exists in a shiny, dark-gray crystalline form and as a shapeless powder.
silicone: Heat-resistant substances that can be used in many different ways, including the rubber-like materials that provide a waterproof seal around windows and in aquariums. Some silicones serve as grease-like lubricants in cars and trucks. Most silicones, a type of molecule known as a polymer, are built around long chains of silicon and oxygen atoms.
tool: An object that a person or other animal makes or obtains and then uses to carry out some purpose such as reaching food, defending itself or grooming.
