10/05/2009 at 07:10 PM EDT
A month after their father was finally laid to rest
, Michael Jackson's children "are doing very good," a source close to the Jackson family tells PEOPLE, and enjoying time together outside their grandparents' home.
On Friday, Prince Michael I, 12, Paris, 11, and Prince Michael II (a.k.a. "Blanket"), 7, visited the California Science Center, a hands-on science education facility, in Los Angeles where they came in with a large group of kids, browsed the gift shop and watched a film in the IMAX theatre.
"They were running around, just having fun with the toys like any other kids would do," Brandon Smith, an employee at the science center's gift store tells PEOPLE. "[They were] real friendly. They said 'hi.'"
The family outing comes a few weeks after the Jackson kids visited L.A.'s famed La Brea Tar Pits and have been spotted in Las Vegas
with their grandmother.
"Katherine wants to give them a normalcy that they've never had," says the family source. "She wants them to adjust to a normal life. She wants to make sure they are grounded."
Reporting by CHAMP CLARK and NINA TYLER