Rewrite the sentence using commas.

Some scientists in San Francisco California filmed skateboarders in action.

I wrote...
Some scientists in San Francisco, California filmed skateboarders in action.

You need a comma after California.

Thank you...I wasn't sure about after Calif. or not

You're welcome.

To rewrite the sentence using commas, you correctly placed a comma after "San Francisco." This is because "San Francisco" is a specific location and should be set off by commas to indicate additional nonessential information.