acceleration: A change in the speed or direction of some object. 

aerodynamic: Having a shape that reduces resistance from air flowing past. 

birds: Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t. 

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. 

centripetal force: A force that acts on an object as it moves along a curved path. This force is directed into the center of the curve or circle. (Centripetal means “center seeking” in Latin.) 

drag: A slowing force exerted by air or other fluid surrounding a moving object. It involves friction. But unlike simple friction, it increases with an object’s speed. 

forage: To search for something, especially food. It’s also a term for the food eaten by grazing animals, such as cattle and horses. 

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. 

fundamental: Something that is basic or serves as the foundation for another thing or idea. 

gecko: A small to medium sized reptile found in warm to equatorial regions of the world. Some 2,000 different species of this lizard exist, in a wide range of colors. These reptiles eat insects, worms and even the occasional small bird. But they are best known for being able to climb slick surfaces, owing to special structures on the bottom surfaces of their feet. 

gravity: The force that attracts anything with mass, or bulk, toward any other thing with mass. The more mass that something has, the greater its gravity. 

inertia: The tendency of a moving object to resist a change in its motion — or, for a resting object, to begin moving. 

insect: A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths. 

lift: An upward force on an object. It may occur when an object (such as a balloon) is filled with a gas that weighs less than air; it can also result when a low-pressure area occurs above an object (such as an airplane wing). 

limb: (in physiology) An arm or leg.  

model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others. 

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). 

navigate: To find one’s way through a landscape using visual cues, sensory information (like scents), magnetic information (like an internal compass) or other techniques. 

parallel: An adjective that describes two things that are side by side and have the same distance between their parts. In the word “all,” the final two letters are parallel lines. Or two things, events or processes that have much in common if compared side by side. 

parkour: A term, from the French, for a type of gymnastics-like activity where people soar through an environment by jumping, leaping and scrambling up, around and between walls and other obstacles. Movements tend to be very rapid and fluid. Some may involve vaulting or flipping over railings, stairs or other structures. People may even climb up walls or leap from one wall or fence to some other structure. 

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. 

predator: (adjective: predatory) A creature that preys on other animals for most or all of its food. 

resistance: (in physics) Something that keeps a physical material (such as a block of wood, flow of water or air) from moving freely, usually because it provides friction to impede its motion. 

risk: The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.) 

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. 

role model: Someone whose skill, behavior and/or personality makes them an inspirational ideal, the type who inspires others to model themselves after this person. 

sprint: To run at top speed over a fairly short distance. In competitive running, the 100-meter race is a sprint. A person who is doing this kind of running is called a sprinter. 

tactic: An action or plan of action to accomplish a particular feat. 

technology: The application of scientific knowledge for practical purposes, especially in industry — or the devices, processes and systems that result from those efforts. 

traction: (in physics) The force created as something pulls across a surface or the glue-like effect of friction created as something moves along a surface. It’s the ability of something to resist sliding, such as a tire on a road or a sock-covered foot along a wood floor. It is not the same as friction but is related to friction.  

turbulent: (n. turbulence)  An adjective for the unpredictable fluctuation of a fluid (including air) in which its velocity varies irregularly instead of maintaining a steady or calm flow. 

van der Waals forces: A type of molecular attraction that works over very small distances. 

vertical: A term for the direction of a line or plane that runs up and down, as the vertical post for a streetlight does. It’s the opposite of horizontal, which would run parallel to the ground. 

vortex: (plural: vortices) A swirling whirlpool of some liquid or gas. Tornadoes are vortices, and so are the tornado-like swirls inside a glass of tea that’s been stirred with a spoon. Smoke rings are donut-shaped vortices. 

vortices: (singular: vortex) Swirling whirlpools of some liquid or gas. Tornadoes are vortices, and so are the tornado-like swirls inside a glass of tea that’s been stirred with a spoon. Smoke rings are donut-shaped vortices.