630 Our Surroundings 



Larva: The young of certain insects in an early stage in life. The 



caterpillar is the larval stage of the butterfly or moth. 

 Larynx (lar'inks) : The upper part of the windpipe; the voice box. 

 Latent energy (la/t<?nt) : Energy not active but capable of activity; 



potential energy. For example, the energy of stored water in a high 



place. 



Latitude: Distance in degrees north or south of the equator. 

 Law: A generally accepted explanation of some natural occurrence. 

 Law of electrical charges: Unlike electrical charges attract each other, 



and like charges repel each other. 

 Law of magnetic poles: Like poles of magnets repel each other, and 



unlike poles attract each other. 

 Lead: A solid, heavy, soft, bluish-gray metal, easily melted. One of 



the elements. 

 Legumes (leg'umz) : Pod-bearing plants or their seeds. Peas and beans 



are examples. 

 Lens: A transparent piece of glass so made that its surfaces are not 



parallel and at least one is curved. Used, for example, in glasses for 



spreading or focusing light rays. The portion of the eye that focuses 



light rays on the retina. 

 Lenticels (len'ti-selz) : Tiny openings in the bark of a woody plant 



through which oxygen enters. 

 Lever (le'ver) : A rigid bar arranged to turn upon a fixed support or 



axis called a fulcrum ; divided into three classes according to the posi- 

 tion of the fulcrum. 



Leyden jar (ll'd^n) : A device for storing static electricity. 

 Life process: Any function of living things necessary for existence. 

 Ligament (lig'd-m<?nt) : A tough band of tissue serving to connect two 



bones, or to hold an organ in place. 

 Light: A form of energy received from the sun or other illuminating 



f body, which acts on the eyes to cause sight. 

 Lightning: The discharge between two clouds bearing unlike electrical 



charges or between clouds and oppositely charged objects on the earth. 



The vivid flash of light caused by such a discharge. 

 Light year: The distance which light travels in one year at the rate 



of 186,000 miles a second. Used to measure distances in the heavens. 

 Lines of force: Imaginary lines indicating the shape and extent of a 



magnetic field. 



Liquefy: To change from a solid to a liquid form. 

 Liquid: A freely flowing fluid, such as water, which tends to take the 



f shape of any container in which it is placed. 

 Litmus paper: A special paper used to find out whether a substance is 



acid or alkaline. Acids turn blue litmus paper red. Alkalies turn red 



litmus paper blue. 

 Liver: A gland which secretes bile and stores glycogen used by the body 



muscles. 



Loam: A soil in which there is a combination of clay, sand, and humus. 

 Lodestone: Magnetic iron ore, magnetite, a natural magnet. 

 Longitude: Distance in degrees east or west from a given meridian. 

 Loud speaker: The part of a radio receiving set that changes waves 



of electric energy into sound waves, which it magnifies. 

 "Low": On a weather map "low" indicates the centers of lowest bar- 

 ometric pressure. In a "low" area the weather is usually cloudy or 



rainy. 

 Luminous: Emitting or reflecting light; shining. 



