Here’s how rainwater might one day power some of your lights

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.

conductive: Able to carry an electric current.

current: (in electricity) The flow of electricity or the amount of charge moving through some material over a particular period of time.

develop: To emerge or to make come into being, either naturally or through human intervention, such as by manufacturing.

electric charge: The physical property responsible for electric force; it can be negative or positive.

electric current: A flow of electric charge — electricity — usually from the movement of negatively charged particles, called electrons.

electrical resistance: The tendency of an electricity-conducting material to oppose the passage of a current through it. That resistance (usually measured in units known as ohms) will convert some of the electric energy into heat.

engineer: A person who uses science and math to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.

environment: The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of things in the vicinity of an item of interest).

fossil fuel: Any fuel — such as coal, petroleum (crude oil) or natural gas — that has developed within the Earth over millions of years from the decayed remains of bacteria, plants or animals.

green: (in chemistry and environmental science) An adjective to describe products and processes that will pose little or no harm to living things or the environment.

hydrogen: The lightest element in the universe. As a gas, it is colorless, odorless and highly flammable. It’s an integral part of many fuels, fats and chemicals that make up living tissues. It’s made of a single proton (which serves as its nucleus) orbited by a single electron.

ion: (adj. ionized) An atom or molecule with an electric charge due to the loss or gain of one or more electrons. An ionized gas, or plasma, is where all of the electrons have been separated from their parent atoms.

LED: (short for light emitting diode) Electronic components that, as their name suggests, emit light when electricity flows through them. LEDs are very energy-efficient and often can be very bright. They have lately been replacing conventional lights for home and commercial lamps.

maximize: A strategy to consider possible options in a move to find the best one. The alternative involves looking at just enough options to find one that is good enough.

mechanical: Having to do with the devices that move, including tools, engines and other machines (even, potentially, living machines); or something caused by the physical movement of another thing.

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).

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).

physicist: A scientist who studies the nature and properties of matter and energy.

Singapore: An island nation located just off the tip of Malaysia in southeast Asia. Formerly an English colony, it became an independent nation in 1965. Its roughly 55 islands (the largest is Singapore) comprise some 687 square kilometers (265 square miles) of land, and are home to more than 5.3 million people.

surface area: The area of some material’s surface. In general, smaller materials and ones with rougher or more convoluted surfaces have a greater exterior surface area — per unit mass — than larger items or ones with smoother exteriors. That becomes important when chemical, biological or physical processes occur on a surface.

sustainable: (n. sustainability) An adjective to describe the use of resources in a such a way that they will continue to be available long into the future.

system: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body’s circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation’s railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.

turbine: A device with extended arm-like blades (often curved) to catch a moving fluid — anything from a gas or steam to water — and then convert the energy in that movement into rotary motion. Often that rotary motion will drive a system to generate electricity.

voltage: A force associated with an electric current that is measured in units known as volts. Power companies use high-voltage to move electric power over long distances.

watt: A measure of the rate of energy use, flux (or flow) or production. It is equivalent to one joule per second. It describes the rate of energy converted from one form to another — or moved — per unit of time. For instance, a kilowatt is 1,000 watts, and household energy use is typically measured and quantified in terms of kilowatt-hours, or the number of kilowatts used per hour.