Imagine you are looking after three young children. They discover a pile of discarded bread crates, office chairs and wooden planks, and want to play. How do you react?
Whatever your decision, you probably won't get it 100 per cent right — parents, teachers and others who work with children never can.
If they intervene, they are overprotective. If they don't, they are negligent.
In the scenario above, most adults would either stop the play or be very directive about how the play can occur, and what objects can be used.
Stopping or restricting play might seem reasonable in the short term, but research shows that, in the longer term, excessive safety can hinder children's opportunities for learning.
So, what's the best solution when children want to play with objects we would not normally think of as toys?
We've all heard the saying that one person's trash is another person's treasure. The adult who discovers the treasure might see beauty or functionality in the trash that wasn't apparent to the original owner.
For children, the trash-to-treasure transfer is a trigger for endless possibilities.
Child development researchers like me, and others who work with children, refer to the trash as "loose parts".
Research has revealed clear physical benefits as well as some social and some creative benefits of loose parts play.
With so many benefits and so much trash available, it seems an easy, fun and cost-effective way to promote children's development.
The main barrier is that adults often see this kind of play as too risky.
Where children imagine building boats and houses, adults imagine catastrophes.
Fostering creativity and breaking down barriers
As part of the Sydney Playground Project, we have introduced loose parts into school playgrounds and included risk-reframing workshops that brought parents and teachers together to consider the benefits of risky play.
Teachers are often concerned they will be seen as neglecting their duty of care if they allow children to take risks, so they restrict play that they know is beneficial for children.
That's why knowing that parents are in agreement about the importance of risky play is important.
Our results and those of a Melbourne-based study both showed an increase in children's play and physical activity, which is important because Australian children generally don't meet daily physical activity requirements.
In the Sydney Playground Project, teachers observing play commented on children's creativity.
What's more, some children who previously had difficulty getting involved in play with their peers, such as children with limited English, were able to join in.
Loose parts play is often discussed amid calls for parents to be less protective and allow their children to roam free.
There is evidence that overprotective parenting and helping children too much predicts child anxiety.
But that doesn't mean we must go to the other extreme of "free range", which doesn't suit all parents or children.
Count to 10 before you intervene
In the Sydney Playground Project, we recommend the 10-second rule.
Let's say we see children stacking some car tyres and climbing on top. The alignment isn't perfect and we can see potential for the tyres to fall and an injury to occur.
Our immediate response is to either tell the children to stop or help by holding the tyres in place.
But, if we do a slow count to 10 and watch what happens, we might be surprised.
Most likely, the children will manage the risky situation they have created.
We have seen some kids place mats under structures to ensure they land on a soft surface or take turns holding unstable structures in place to provide additional support.
Sometimes children ask for adult assistance. Children know that adults are generally stronger and taller, and that's a good opportunity to be involved without interfering.
It's also important to remember that risk-taking is relative to the child.
For one child, a small climb and jump may feel risky. Another child may need climb stacked objects above their height before they start to experience the feelings of uncertainty associated with risk taking.
Importantly, in loose parts play, all children can play together.
Unlike traditional play structures such as climbing frames, there are no clear goals to achieve. There is no pressure to take risks that children would prefer to avoid.
If there is potential for a serious accident, then of course it is important for adults to intervene.
But injury rates were monitored during the Sydney Playground Project loose parts play interventions and although the play was perceived as riskier by adults, it didn't actually result in an increase in injuries compared to play in normal playgrounds.
It's also important to remember that while we want to avoid anything serious, minor injuries that lead to cuts, scrapes and bruises are important in learning the consequences of actions.
There are very few flat, soft and predictable surfaces in the world.
Skills acquired on the playground can build the foundations for enjoying the pleasures of life, such as exploring old and modern cities, rural landscapes and the Australian bush.
Dr Shirley Wyver is a senior lecturer in child development at Macquarie University.