Why do we get wrinkled skin when we are in water?

by 5b at Eiksmarka primary school. This year's Nysgjerrigper 2005.

I wonder why!

The primary school pupils have a mail box in their classroom where they can put all the questions they might have. After a while the mail box is full, and at this point, they go through the questions. The teacher helps them to choose the questions that they can do research on. Three questions grab their interest: How can we make fresh bread stay fresh? Why do we have hair? Why do we get wrinkled skin when we are in water? The last question “wins” – the pupils imagine that they can do many fun activities when researching this question.

Why is it like this?

The pupils set up three hypotheses:

• The skin pulls itself together or is extended when it is in water
• Something under the skin pulls itself together so that the skin wrinkles
• The skin absorbs water

They limit the task by researching the skin on the hands alone.

Draw up a plan for the investigation!

Soon the list of activities grows big. The pupils want to do many experiments – both on land and in water. They plan a research session in the swimming pool, and they want to test how their skin reacts to water with different kinds of additives, for example Fairy liquid and food colouring. They also want to rub their skin with Vaseline and butter in parts of the experiments.

Before the swimming pool experiments are carried out, the pupils have done much planning. Amongst other things, they write an application for 800 kr. (about €100) from the class’ money box to cover the swimming pool fee. The application is directed to the leader of the parents’ group, and, luckily, the money is granted. The pupils also write letters to their parents to get transport to and from the swimming pool. They make detailed plans to coordinate the transport in the best way possible.

They want to contact experts on the field, and do this by e-mail or personal interviews.

The pupils are divided into several groups and have different areas of responsibility. To make sure that the research is appropriately documented, two of the pupils are in charge of photographing.

Gathering information!

In the swimming pool, they test what happens to their skin after they have been in water for five minutes, fifteen minutes, half an hour, and one hour. The results are carefully logged in tables with wrinkle-degrees from “not wrinkled at all” to “extremely wrinkled.” Most of the pupils have a stable and fairly similar wrinkle-development, with the exception of one of the girls - after 23 minutes she starts to feel her palate wrinkle!

They also do some experiments in a sauna, and register that the wrinkles quickly disappear here. With a measuring tape they measure around a finger to see whether it has grown larger or smaller. To have something to measure by, they mark their fingers with a waterproof pen. This experiment is not so successful – the waterproof pen turns out not to be completely waterproof after all.

Back in the classroom, the pupils test how their skin reacts to water at different temperatures and with different additives. They also prick themselves with needles to see if water trickles out of the wrinkles.

One of the skin doctors they contact invites them to Rikshospitalet, a university hospital in Oslo. They prepare fourteen questions, for example: Does the skin get damaged by chlorinated water? Why do we not get wrinkles on our stomachs? Why does the skin pinch when it is in 50º C?

Four other skin doctors answer their questions by e-mail. One group also interviews the proprietor of the Askepottsalongen, a local skincare salon.

What we found out!

Through their own experiments and answers from the experts (even though the answers differed somewhat!), the pupils conclude that we get wrinkles when we are in water because the layer of fat on the skin is rinsed off. The skin absorbs water and expands, and the fat on the so-called horned skin disappears. The horned skin is thickest on the fingers (and feet), this is why we get the most wrinkles there – or a swelling in the skin, as one of the skin doctors points out. Thus one of the hypotheses is falsified, while the hypotheses that the skin expands when it is in water and that the skin absorbs water are strengthened.

Tell everyone else!

The pupils document the process thoroughly and with great neatness in a huge report. The report is spiced up with pictures, drawings, and comprehensible tables from the research.

The fifth grade pupils win the Nysgjerrigper Prize 2005 for their research work. The jury stress that they have completed research of high quality in real Nysgjerrigper spirit. The experiments are highlighted as creative and good, and when the results turn out to be different than expected, the pupils show their ability to reflect over what went wrong.