Science News Archive

Is it one of your favourite things?

If raindrops on roses are some of your favourite things, then here is some news for you. A study has come out this week that reveals why it is that drops of water cling to rose petals in that most beautiful of ways.

Lots of flowers and leaves are covered in spines and a layer of wax which repel water and cause it to slide off taking dust with it, a process known as self-cleaning. But this doesn’t happen in roses, where water droplets cling on instead.

Now scientists from Tsinghua University in Beijing have worked out what is going on – rose petals are also covered in spines but they have no wax. Rows of spines along wide smooth furrows keep the water in spherical droplets and hold on to them

What’s more the team made a cast of a rose petal out of polyvinyl alcohol and found that this manmade substance had the exact same ability to cling onto water as a real rose petal. So, a bit like geckos feet, the stickiness of petals relies on their physical structure and not so much the chemical composition of the material they are made of.

It is thought that rose petals might benefit from holding water droplets because it makes them glimmer and attract pollinating insects. Scientists also think that understanding the rose petals’ stickiness could lead to some interesting developments in the lab, when tiny amounts of liquids need to be moved around without contaminating each other.

27th Apr 2008