5 Things to Watch for Day 2 of DNC

— -- Democrats brought the drama to Pennsylvania, and we’re only a day in.

Big name political stars — including Hillary Clinton’s former rival Sen. Bernie Sanders, Sen. Elizabeth Warren and first lady Michelle Obama — took the stage Monday, but it was the action on the floor that created the most fireworks.

Reeling From the Fallout

The Democratic National Convention did not get off to a smooth start on Monday.

The bumpy ride began with a last-minute switch of the opening speaker. Democratic National Committee Chairwoman Debbie Wasserman Schultz — who had announced that she would be stepping down after the convention because of the drama surrounding the leak of DNC emails, which appear to show party officials supporting Clinton over Sanders — was originally set to gavel the convention into session but then bowed out.

Instead, Baltimore Mayor Stephanie Rawlings-Blake formally started the convention. And at first, she forgot to use the gavel.

After that, the first three hours were full of outbursts and boos from Sanders supporters.

Roll Call Could Get Raucous

The first hours of the convention were rowdy as the floor broke into jeers throughout several speakers’ addresses.

The very first mention of Clinton sparked a round of “Bernie!” chants, which continued for much of the early part of the program.

The state roll call vote on the nomination, scheduled for late this afternoon, is going to pose and even bigger opportunity for any disgruntled Sanders voters to show their displeasure.

Both Clinton and Sanders have had their names placed into nomination for president at the convention.

This is largely a technicality, since bound delegates will vote for their candidates even if a name isn't in nomination. But it's a symbolic gesture for his supporters, and per party rules, it means more Sanders time on the convention floor today.

Maternal Movement

One of the more emotional moments among tonight’s speeches will likely come when the Mothers of the Movement take the stage.

The group, consisting of women who have lost their children to gun violence or excessive police force, includes Trayvon Martin’s mom, Sybrina Fulton; Michael Brown’s mother, Lezley McSpadden; and Eric Garner’s mother, Gwen Carr.

The circumstances of their children’s deaths may be different, but all the women have endorsed Clinton’s campaign.

Protests in Philadelphia

Hundreds of protesters took to the streets in Philadelphia on Monday, and the drama in the city and outside the convention center seems unlikely to let up.

The demonstrations have generally been bigger than the ones held last week during the Republican National Convention. As in Cleveland, there have not been significant reports of violence.

There were no arrests as of Monday night, but multiple people were detained, police told ABC.

Bill Clinton Takes the Stage

One of Hillary Clinton’s most active surrogates was been her husband, former President Bill Clinton, and now he’s headed to the main stage.

He arrived in Philadelphia on Monday and attended a reception for members of Congress.

Clinton has a history of making an impact at Democratic conventions. In his lauded speech at the 2012 gathering in Charlotte, North Carolina, he made a 48-minute, wonky case for President Barack Obama’s re-election.

ABC News’ Rick Klein and Ryan Struyk contributed to this report.