This we know: Facebook is to political outrage as, say, water is to otters. It's a matter of survival.

CNN and Facebook are teaming up to harness that emotion, for the first Democratic presidential debate on Tuesday night, when Bernie Sanders and Hillary Clinton face off and emotions are likely to be high.

CNN and Facebook hope to have the viewer surrounded. CNN has the first screen — television — while Facebook has the second screen, the social networks where people go to comment on what they're seeing. The two will work together in real time, with CNN measuring viewers’ reaction to the biggest moments using Facebook and incorporating that data both during the primetime debate and in post-debate analysis on the network’s airwaves and digital properties. CNN will get access to Facebook's viewer metrics during the debate and anchor Don Lemon will ask the candidates questions submitted through Facebook.

In other words: old media and new media are making friends.

Call it enlightened self-interest. According to the Pew Research Center, Facebook was the second most popular source of political news among Internet users, with local television coming in first.

Andy Mitchell, Facebook’s director of News and Global Media Partnerships told Mashable that the company is working with CNN to make the social website the "richest second screen experience."

"Being able to represent the political discourse is a big part of what people go to Facebook for," Mitchell said.

"The reality is, when people watch an event like a debate, it’s become an inherently social event," Andrew Morse, CNN’s Executive Vice President of Editorial, told Mashable last week. "You need a platform to do that. To be able to have that 'second screen' that is not a prosthetic limb, [that is] seamlessly flowing between TV and happening on Facebook — it’s a really neat concept. It’s a really elegant dance in certain ways."

The dance floor is a crowded one. Since January 1, Facebook has seen more than 1 billion interactions — posts, comments, likes and shares — related to the 2016 presidential race.

CNN, which has nearly 19 million fans on Facebook, will be the first page, as opposed to an individual, to use the social network's new video streaming function.

The ability to stream live video from Facebook Mentions, which was introduced in an August update to the app, had been exclusively restricted to public figures with verified Facebook pages.

CNN senior digital correspondent Chris Moody will host roughly a half-dozen livestreams leading up to Tuesday’s debate that will take viewers “behind the scenes” of the experience. Representatives from both CNN and Facebook declined to provide specific advance details about the content of the broadcasts.

Earlier this month, CNN also introduced the "#CampaignCamper," an Airstream with a video booth that recently completed a cross-country tour to engage with voters on political issues ahead of the debate.

Described by CNN as a "rolling production studio," the camper made stops in cities like Ferguson, Missouri; Des Moines, Iowa and Lafayette, Louisiana and allowed voters to record video questions that may be aired in future presidential primary debates or uploaded to the CNN Facebook page. The stops were picked, in part, by Facebook’s data surrounding political conversation.

This election season, CNN and Facebook bring you the ultimate vehicle to make your voice heard: the... Posted by CNN Politics on Saturday, October 3, 2015

The two are fending off increasing competition. The debate partnership could make Facebook, for instance, seen as more of a destination for video and current events, a competitive market with already popular apps like Twitter, Periscope — which is owned by Twitter — and Snapchat.

Facebook also partnered with news organizations in the last presidential election but has tightened its ties with CNN, in particular. The Oct. 13 debate is the first in a series of co-branded Facebook and CNN debates throughout the remainder of the primary season.