How to deal with change
But the National Children's Bureau has launched a campaign that highlights superficially good events which can leave primary pupils with a sense of loss.
Sacha Richardson, a psychotherapist who has helped the bureau with its campaign, said: "For children growing up, life is full of change. And change always involves some loss. It's helpful to have space to acknowledge it's not all wonderful."
A sense of loss at home can manifest itself at school. Children may become unsettled and insecure. Confidence may dwindle and they may cling to their carers.
The bureau has produced materials, including a DVD, to help teachers address childhood anxieties around bereavement and loss.
Alison Penny, of the bureau, believes adults often shrink from tackling difficult subjects directly. "Teachers need to find opportunities within the curriculum to deal with death and loss," she said. "If questions aren't acknowledged, children can think this is something they're not allowed to talk about."
Mr Richardson believes that teachers should be aware of the potential impact of change and help pupils to express negative emotions. "Reality is not all sweetness and light," he said. "You could say, 'That's good for some people, but others find it difficult'. That gives permission for both reactions."
And school can provide a sense of continuity that is lacking at home.
Teachers can offer children a level of choice in the classroom, which compensates for the loss of control elsewhere.
Mr Richardson said: "The more children learn that we all have different feelings and reactions, the more emotional understanding they'll have.
"If a child comes from a family where there's no place to express feelings around loss, school may be the only place they're able to think about it."