Image source, Getty Images

As part of our investigation, reporters Harriet and Andy set up a profile for 'Ash', a 15-year-old from Bristol who loves the gym, gaming and music - especially drumming.

Despite showing no initial interest in violence, Ash was almost immediately shown disturbing YouTube videos reviewing different weapons and how they affect the human body.

TikTok also showed an array of worrying content, from "how to hide a dead body" to guides on how to hide drugs from police.

There were also hints of adult and potentially misogynistic videos, with later clips showing more and more women dancing suggestively and one post asking the user to choose whether they preferred "the girl or the car".

BBC Radio Bristol presenter: Joe Simspublished at 07:39 British Summer Time

07:39 BST

'We're out of our depth. This murky online world it does feel like the Wild West, it does feel relatively lawless, and we just wonder what we're exposing our kids to.

'It's shocking for you because you didn't grow up around it, but if this is something that teenagers are looking at on a regular basis then these kind of things are normalised. And there's an assumption, because they haven't got enough context, that it's something that adults have always done since time immemorial.

"As you're going and straddling that horrible world of adolescence then they're looking to culturally assimilate. And if that's what they're being shown then that's what they believe to be something that all adults are doing."

Image source, Getty Images

As part of our investigation, which you can read in full here, we set up Instagram and TikTok profiles for 'Sophie' - a 15-year-old from Dursley, who likes Taylor Swift and romance and fantasy books, as well as spending time with friends, cute animals and mindfulness content.

What stood out about her social media feeds was how quickly the posts turned to content about mental health, including several TikTok posts about young people who had taken their own lives after being bullied, showing their gravestones.

Sophie was also exposed to videos where people spoke about wanting to end their own lives, and others concerning self-harm - though many of these were celebrities urging fans not to harm themselves.

Image source, David Wright

Earlier this week we shared the findings of our investigation, in which we set up social media accounts for six fake teenagers, with David Wright, the director of the UK Safer Internet Centre at SWGfl, an online safety and security organisation.

He said the content we showed him "presents serious risks to children's mental health and wellbeing, and we have all too often seen the tragic consequences".

"Exposure to such material can, in some cases, normalise harmful behaviours, lead to emotional distress, and significantly impair children's ability to navigate the online world safely," he added.

Image source, Getty Images

Over the course of the day we will be hearing a lot about the harmful content children are seeing on social media platforms.

But actually getting inside the algorithms that dictate the content teens are seeing on their feeds was another challenge entirely. As BBC journalists, how could we possibly understand what kids in our area are really accessing online?

Well thanks to Sophie, Maya, Aisha, Harry, Ash and Kai - all of whom are 13 to 15 - we got direct access to the feeds of teenagers on Instagram, TikTok and YouTube.

We should say that none of these teenagers actually exist. All of them were set up by our journalists Harriet Robinson and Andy Howard as part of a week-long investigation into how teenagers see harmful content online.

For seven days, Andy and Harriet scrolled for 10 minutes a day as the teenagers - screen recording everything they saw.

Throughout the course of the day we'll hear about what these fictional teenagers were exposed to, from innocent scrolling to graphic videos on mental health and violent crime - and what social media companies are doing to try and limit harm.

Students from King's Oak Academy in Kingswood spoke to Amanda Parr about the sorts of things they are exposed to online and how it influences their real-life relationships.

Image source, Getty Images

We've been speaking to teenagers about the sort of material they are exposed to online, how it makes them feel and how it impacts their relationships and mental well-being.

Two of our reporters have spent the last few weeks creating fictional teenage profiles to show how the sort of content young people are shown on their accounts, even if they don't search for it.

Later in the day on BBC Radio social media experts will be offering their advice, solutions and analysis.

And tonight on BBC Points West we will have more practical advice for young people and their families to help keep them safe.

Stay with us throughout the day for updates and information.