IF you can't decide what to give that special child for the holidays, why not give him or her the entire planet? SimEarth, a new computer program introduced this month, is a planetary construction kit. More than a computer game, this program brings a complex simulation of geology, weather, and life to home computers.
Using SimEarth, children can create a prehistoric model of the Earth, complete with single-celled life forms. Then they can speed up time, sit back, and watch evolution happen. By changing the flow of magma under the surface, children can make mountains and earthquakes. The simulation even lets them introduce higher life forms or give high technology to the simulation's neolithic natives.
``It's as accurate as we can get it,'' says Sally Vandershaf, a spokeswoman for Maxis, the California company that designed the system. SimEarth is based on scientist James Lovelock's Gaia hypothesis, the idea that the Earth is a single organism, its geology, geography, and life shaping and interacting with each other. The program even simulates continental drift.
``I think that it is really good,'' says Natalie Rusk, the education coordinator at the Boston Computer Museum. ``One of the most important things about computers for scientists ... is simulation. This gives people a feeling for that.''
SimEarth is one of a bounteous crop of computer programs for children that have sprung up in computer stores this fall. The better programs, says Ms. Rusk, stay away from arcade-like graphics and instead encourage exploration and creativity.
Other experts agree. ``A game like `Invaders' will teach them eye-hand coordination,'' says Elaine Poltz, a mother of two and a specialist on educational software for the Boston Computer Society. ``But it won't teach them about anything.''
Parents should also be wary of ``drill and practice'' programs designed to ``make learning fun,'' says Rusk. She advises parents to stay away from ``medicine that is sugar-coated.''
``Some of the math drill programs try to take `five times three' and make it fun with spaceships: If you answer `five times three' correctly, you are allowed to shoot a spaceship,'' she says. These programs set the computer up in the child's mind as infallible teacher, rather than a tool for exploration and empowerment.
Children who are interested in ecology but not yet ready to run the world with SimEarth will likely enjoy EarthQuest, a science and geography game introduced last fall for the Apple Macintosh computer. EarthQuest lets a child explore the planet, its peoples, and the environmental problems that we now face. One of the program's screens shows the child a variety of animals and plants; when the child ``clicks'' on an animal with the computer's mouse, the program displays information about the animal, plays a recording of the animal's noises, or shows a tiny movie.
The program has on file the sound of human languages like Croatian and Swahili, music from around the world, and an encyclopedic database on subjects ranging from the problems caused by oil spills to the orbit of Jupiter around the sun.
EarthQuest also has a trivia game that tests young minds about science, history, and geography. ``It's challenging and you learn stuff,'' says Tom McArdle, 9, who used the program at the Boston Museum of Science.
A moment later, the program asked Tom for the name of the lowest layer of the atmosphere. Tom clicked his answer: Troposphere. ``Oh, we're learning that stuff in school,'' he explained.
But unlike school - and the majority of so-called educational software - the best software for kids lets them choose what they want to do and the order they want to do it in.
``A lot of parents think that `anything that is going to teach my kids something is going to be good.' That's not always the case,'' says Rusk. Many programs for children take a directed, step-by-step approach in the information that they present. ``The kids soon figure out that the program is trying to get them to do something'' and lose interest, she says.
There's only one reliable way to tell a good program from a bad one, says Rusk: ``You have to try it. I don't know how much you can tell from the package.''
Some of the newest and most exciting software for very young children - ages 2 to 6 - is by Walt Disney Computer Software in Burbank, Calif. The programs combine music, recorded speech, and animation to let a preschooler explore and solve games.
In ``Mickey's ABCs,'' the child directs Mickey Mouse around his house. Press ``B'' and a woman's voice says ``B is for Bathroom,'' and Mickey walks into his bathroom. Press ``B'' again and Mickey brushes his teeth as the woman says ``B is for Brush.''
``That's better!'' says Mickey, when his teeth are clean.
All the Disney music and voices come out of a $29.95 ``sound source'' that plugs into the back of a standard IBM PC computer. Disney has a whole series of programs that use the sound source, ranging in price from $14.99 to $39.99.
``This sells very well, and it is not expensive,'' says Berge Jololian, assistant manager at Egghead Software in Cambridge, Mass. ``I would say if you are looking for a game for a child, this is the game - provided that you have a [color] monitor.''
Parents shouldn't worry about buying a program that is a little too difficult or advanced for their child:
``One of the things that I have found is that [computer software] provides an excellent opportunity for an adult and a child to work together,'' says Joan Milman, manager of the Computer Discovery Space at the Boston Museum of Science. Parents can make programs with a lot of reading more approachable by doing the reading with the child, says Ms. Milman. If the program is about geography or history, the parent can take out a map.
``People tend to think of a computer as a one-on-one activity,'' says Milman. But in the Computer Discovery Space, there are several stools in front of each computer because ``people want to work together. ... The interaction, that time spent, is invaluable.''
BEFORE rushing out to buy software, the Boston Computer Society's Poltz suggests that families look at the wide array of public-domain software that is available. Many public-domain programs are just as good as commercial ones; moreover, children can freely and legally make copies of public domain software for their friends or to take to school. Public-domain software is available at many computer clubs, as well as some computer stores and libraries.
Lastly, Rusk says that parents shouldn't overlook word-processing programs and paint systems when thinking about software for their children. ``What do adults want to use computers for? The most popular thing is word processing. ... I don't think that it is different for kids,'' she says. Children might need a simplified program with fewer formatting options, and there are many such programs available.
Playing with computer games in the Egghead Software store, Ben Spatz-Rabinowitz, 11, agrees: ``I want something that draws graphics. I want to try to make a computer comic book. You know, like that Batman thing that's out? I want to make something like that. It's not going to be nearly as good, though.''
Just wait and see.