The video of a child’s birthday party — complete with a clown and what seems to be the Israeli version of the hokey-pokey — is sweeter than ice cream cake.

Because of this — and because it is shown by Noam Bedein, who almost eagerly announces “I’m from Sderot, Israel” — one knows the sweetness won’t last.

Just as the clown puts her left foot in and takes her left foot out, a rocket warning blares over the town’s P.A. system — and shakes everyone about. Children, adults and even the clown frantically clamor for shelter; residents know they have only about 15 seconds until rockets or missiles fired from Gaza will fall on them. Bedein hammers this point home by inserting a countdown into the top of the frame.

And at zero, carnage commences. Bedein splices together images of several of the fires and explosions he’s personally filmed — “This one was right behind my house,” he calmly intones as the film rolls on.

Flames leap high into the dark, hot night. Children and adults weep or, even more disturbing, experience epilepsy-like fits of shaking due to the shock. Medical personnel retrieve a body part — who can tell what? — out of the bloody street.

Bedein grimaces at the film he created. He moved to Sderot to attend Sapir College. Instead he’s ended up becoming “a rocket chaser.”

The 25-year-old founder of SderotMedia.com — which began 18 months ago as a handful of college students toting video and still cameras in a beat-up old car — visited San Francisco this week as part of an aggressive Zionist Organization of America itinerary in both Northern and Southern California. Locally, Bedein visited five high schools and colleges and three Jewish community events over a few days.

On the face of it, his message sounds contradictory. In one breath he notes that he’s had the opportunity to shepherd reporters from the world’s biggest newspapers and television stations through Sderot, yet he then complains bitterly that Sderot’s story is not being told.

It’s a claim that requires some explanation. Sure, Bedein concedes, the plight of Sderot as a virtual bombing range is well reported. How the attacks affect the city’s 20,000 residents is not.

“Every day there are reports of how two Kassams [rockets] hit Sderot, there was no harm done and off to the weather report. Can they understand the shock and trauma of that? Only when it bleeds it leads,” he says in perfect,

accent-free English (he is the son of American-born journalist David Bedein and grew up in a settlement near Jerusalem).

“Once you have experienced a rocket landing nearby, your life is changed from that moment.”

And everyone in Sderot has had that experience. Bedein recalls visiting a kindergarten class in which a teacher was showing her students a snail. When she asked the class why the snail had a shell, the response was instantaneous: “To protect from the Kassams!”

Life in Sderot has become one vast waiting game, he explains. Drivers habitually roll down their windows and lower their radios, so they’ll hear the warning sirens. No one wears a seat belt anymore — no one wants to take that extra second to unbuckle it when the siren wails — but since drivers tend to hit the brakes once the alarm sounds, belt-less motorists are being injured more frequently.

Through ZOA tours, Bedein has been on more U.S. college campuses than the ESPN Gameday crew. And it shows — he expertly spouts memorized talking points of how many rockets have been launched toward Israel in various intervals (4,500 since disengagement, incidentally, with about 50 percent aimed at Sderot, only a mile from Gaza).

Coupled with his arresting films and photographs, Bedein advocates a military intervention in Gaza sooner rather than later. The terrorists — 97 percent of whom fire their projectiles from civilian centers, he notes — are only getting stronger. Barrages of rockets are timed around major dates such as Israel’s upcoming 60th anniversary, or in the morning hours when children walk to school and their parents travel to work. Sooner or later the terrorists will wipe out a bus or classroom full of kids and Israel will be forced to react. Bedein wonders: Why wait?

Israeli military and political leaders “see charts in front of their eyes. They’re weighing the sacrifice of soldiers, [Palestinian] lives, civilian lives. It’s too great a scale for them to deal with.

“But it’s just a matter of time” before the terrorists “score a direct hit on a kindergarten classroom — and then Israel will have to go to Gaza.

“Until then,” he says, “we have to wait. The hardest thing about living in Sderot is knowing that.”