Kate also took part in an activity where students shared objects that represent something that makes them feel good.
The study, which will run until 2021, aims to give schools new, robust evidence about what works best for the mental health and well-being of students.
'This is a photograph of my family.
Middleton brought in the popular Christmas family photo to share with everyone and said her husband and children are what make her happy. "We like playing outside together and spending lots of time together. and that makes me feel very happy".
Matthew Kleiner-Mann, chief executive of the Ivy Learning Trust, who met with Kate, said afterwards to the Daily Mail that she told them how "One stirs the flour, one puts the milk and butter in, and they make salads and stuff".
Fans also drew comparisons to the children's character Evil Pea, who sports a furrowed brow which resembles the shape of Kate's pockets.
Kate looked impressed and replied: "This is what you can do if you don't use social media - a fantastic advert".
"As a society, we are much more open about our mental health than ever before, but the modern world has brought new pressures for children, while potentially making others worse", Hinds said. The duchess also found out more about how the school supports pupils and teachers, as well as joining a roundtable discussion about teacher wellbeing.
When Ms Zafirakou explained the different types of printing taught in her classes, Kate said with a laugh: "I'm desperate to go back to tie dye".
Saying hello to Herbie the school dog at Lavender Primary School!