1. Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire. In addition, electricity encompasses less familiar concepts such as the electromagnetic field and electromagnetic [...]
1. A knife (plural knives) is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools. Originally made of rock, flint, and obsidian, knives have evolved in construction as technology has, with [...]
1. In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word “cement” traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed rock with burnt lime [...]
1. In ice hockey, the goaltender wears specialized goaltending equipment to protect him or her from the impact of the puck and assist him or her in making saves. Most modern goaltending equipment is made from the same basic materials: hydrophobic synthetic leather and nylon on the outside; dense closed-cell foams and plastics inside. Pads [...]
1. A sulky is a lightweight cart having two wheels and a seat for the driver only but usually without a body, generally pulled by horses or dogs, and is used for harness races. The term is also used for a light stroller, an arch mounted on wheels or crawler tracks and used in logging, [...]