July 29, 1986

A huge bomb planted in a car devastated a three-block area in a Christian suburb of Beirut today, killing 31 people and wounding 120 others. ''This is carnage,'' said Joseph al-Hashem, a Christian member of the Cabinet, after inspecting the burned buildings and twisted steel in the suburb, Ain al Rummaneh. Hours after the blast, which occurred during the morning rush hour, a large cloud of smoke hung over the area as workers searched for civilians who might still be trapped in the rubble. Firefighters struggled against flames that destroyed three blocks of apartments. The police declared as many as 30 other buildings within 500 yards of the bombing uninhabitable. #7 Blasts This Year It was the seventh explosion in Christian districts this year, and the most devastating. No group has taken responsibility for the previous six explosions, in which 60 people were killed and 350 wounded.

Secrets gleaned from rocks on land and vents on the ocean floor, from probes far into space and deep inside living cells are producing what researchers call an exciting and dynamic new phase in the search for the origin of life. Many experts say that the insights arising from this research are certain to change the understanding of mankind's place in the universe and of the nature of life itself. Scientists describe the emergence of life as one stage in a history of cosmic change, a result of the constant reassembly of matter since it was created in the ''Big Bang'' that scientists believe gave birth to the universe some 15 billion years ago. It is a history of physical and chemical evolution that eventually, on earth and presumably on other heavenly bodies, gave rise to organic molecules and then to living organisms.

Battered by imports and slack demand, many of the nation's largest steel companies looked to labor three years ago to cut costs and help them become more competitive. After painful negotiations, the United Steelworkers of America reluctantly agreed to as much as $1.8 billion in concessions. This year, with the industry in even more woeful shape, the companies have come back for more. But while the union's strength has weakened along with that of the companies, the steelworkers, under a new president, Lynn R. Williams, are struggling this time around to get something in return. Still willing to grant concessions, the union is demanding that the companies open their books to prove ''dire'' need, and provide stock, profit sharing or other compensation for any new givebacks. And it contends that new cuts are only part of the solution, stressing the need for other kinds of company efficiencies and for greater protection against imports.

Consumers in the Northeast and the Middle West are feeling the effects of the great Southern drought as the prices of poultry, eggs and many vegetables and fruits have reached the highest levels in months. The drought, the fourth to hit the region in seven years, in combination with the heat has caused wholesale poultry prices to increase 25 percent since May, according to the Department of Agriculture. To the consumer, this means the retail price of chicken is expected to rise 5 to 10 cents a pound in the coming weeks. The increase reflects depleted supplies and increased prices for a number of commodities produced in the arc of drought that stretches from Alabama to southern Pennsylvania.

DISASTER in the classroom often results when school administrators translate educational research into standardized teaching programs. This warning is issued by Miles Myers, president of the California Federation of Teachers and former administrative director of the National Writing Project at the University of California at Berkeley. He urges teachers to ''resist the efforts of researchers and school administrators to pose as the architects of lesson design.'' In an article, ''When Research Does Not Help Teachers,'' in the summer issue of American Educator, a publication of the American Federation of Teachers, Mr. Myers says research findings can be useful to teachers, but only when the decision of how to adapt them to particular classroom needs is left to teachers.