By AMY HARMON


DEER PARK, New York - Her grandfather wanted to play tea party, but Alexandra Geosits, 2, insisted she had only apple juice. She held out a plastic cup, giggling as she waited to see if he would accept the substitute.

That they were over a thousand kilometers apart, their weekly visit unfolding over computer screens in their respective homes, did not faze either one. Like many other grandchildren and grandparents who live far apart, Alex and Joe Geosits, 69, have become fluent in the ways of the Web cam.

“Delicious,” Mr.Geosits exclaimed from Florida, pretending to take a sip from the cup, which remained clasped here in Alex’s small hand. Video calling, long anticipated by science fiction, is filtering into everyday use. And two demographic groups not particularly known for being high-tech are among the earliest adopters.

In a way that even e-mailed photos never could, the Web cam promises to transcend both distance and the inability of toddlers to hold up their end of a phone conversation.

Some grandparent enthusiasts say this latest form of virtual communication makes the actual separation harder. Others are so sustained by Web cam visits with services like Skype and iChat that they visit less in person. And no one quite knows what it means to a generation of 2-year-olds to have slightly pixelated versions of their grandparents as regular fixtures in their lives.

But at a time when millions of people around the world are beginning to beam themselves across the ether, the Web cam adventures of the nursery school set and their grandparents offer a glimpse at what can be gained - and what may be lost - by almost-being there.

“We would be strangers to them if we didn’t have the Web cam,” said Susan Pierce, 61, of Shreveport, Louisiana, about her grandchildren in Jersey City, New Jersey.

Over the last year, Ms.Pierce and her husband watched Dylan, 17 months, learn to walk and talk over the Web cam, and witnessed his 4-year-old sister Kelsie’s drawings of people evolve from indeterminate blobs to figures with arms and fingers and toes.

But the powerful illusion of physical proximity also sharpens their ache for the real thing.“You just wish you could reach out and cuddle them,” said Ms.Pierce, a nursing professor.“Seeing them makes you miss them more.”

Nearly half of American grandparents live more than 320 kilometers from at least one of their grandchildren, according to American Association of Retired People. Professor Merril Silverstein, a sociologist at the University of Southern California, has found that about two-thirds of grandchildren see one set of grandparents only a few times a year, if that.

But many grandparents find that the Web cam eases the transition during in-person visits, when grandchildren may refuse to sit on their laps or may reject their hugs because they do not recognize them. As one Web cam evangelist wrote on her blog, www.nanascorner.com: “You’ll be able to pick up where you left off without those warming up to you, awkward moments.”

The adult children in a family have their own reasons for encouraging the Web cam enthusiasm of the younger and older generations. When Martha Rodenborn discovered that Elena, now 4, would sit happily in front of the computer in their New York City apartment while her grandmother read her piles of picture books from Ohio, the Web cam quickly became a vehicle for remote baby-sitting.

“It was a lifesaver,” said Ms.Rodenborn, who graduated from Columbia Law School in New York last spring.

Because the Web cam connection is free, parents often keep it on as long as a grandparent is willing to make funny faces and animal sounds. The recent inclusion of Web cams in most laptops helps account for the 20 percent growth in video calling over the last year, said Rebecca Swensen, an analyst at the technology research firm IDC.

About 20 million people around the world have made a video call for personal communication in the last month, Ms.Swensen said. American soldiers in Iraq beam themselves home over Web cams; parents on business trips (including President-elect Barack Obama) bid goodnight to their children, faceto- onscreen-face.

Barbara Turner once sang her fussing newborn grandson to sleep from Ottawa, watching as her son rocked him in Indiana. She said she could almost feel the baby snuggling against her shoulder.

But recently Ms.Turner and her husband rushed to Indiana to be on hand for the birth of her second grandchild.“Some things you just can’t do over the Web cam,”she said.“You make the trip.”