Monthly Archives: May 2013

How to make a paperclip float

One of the forthcoming activities we are creating is about testing things that float, so here’s an experiment of how to make something float that normally sinks.

All you need float is a bowl of water, a paperclip and some tissue paper.

If you try making a paperclip float in water simply by dropping it in, the chances are it will sink to the bottom, as in this photo.

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However, follow these steps and you may find it floats on the water for some time.

1)      Fill a bowl with water

2)      Place a single sheet of tissue paper flat on the surface

3)      Very carefully, lay the paperclip on the tissue

4)      Using a pencil or finger prod the tissue paper into the water

5)      Hopefully, the paperclip should rest on the surface

If the paperclip floats, this is because it is lying on the “skin” of the water. Water particles have a positive and negative static charge. Because opposites attract, they stick together and create the skin effect, known as surface tension. Simply dropping the paperclip into the water can disrupt this balance, but the gentle actions of lowering the tissue and then the clip, then removing the tissue, allow the surface tension to be maintained.

ImageIn this image, you can see the gentle imprint the clip makes in the water. You might see a similar effect with water insects, especially now it’s spring time. In the below picture, see how the pond skaters’ legs gently depress the surface. The skater uses the water’s skin to its advantage, enabling it to travel over the surface of the pond without sinking.

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Let us know if you have any luck with it or capture any good pond skater photos!

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Scientist under the microscope: Marie Curie

We Love Science wishes to commemorate an exciting historical scientist – Marie Curie. She’s a well-known figure (she even has a charity shop named after her!) but what exactly did she do?

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Curie was an admirable scientist for many reasons. Not only was she a woman facing great opposition in the male-dominated world of science, her efforts helped save and treat many injured people in the First World War. Curie was the first woman to be awarded the Nobel Peace Prize, and the only person to win it twice.

Working with her husband, Pierre, she discovered that when nuclei break down they produce radiations. This means that they are radioactive, a term the Curies coined. They discovered two radioactive elements – polonium and radium.

Following Pierre’s death and during the First World War, Marie worked to develop mobile X-ray units that could be used to diagnose injuries at the battlefront. The International Red Cross made her head of its radiological service and she held training courses for doctors.

During their research, the Curies fell sick and physically exhausted. These effects have been retrospectively diagnosed as symptoms of radiation sickness. They nonetheless persevered, often with raw and inflamed hands caused by handling radioactive material. Curie herself died of prolonged exposure to radiation.

Because of her research into x-rays and the treatment of cancer, the charity Marie Curie Cancer Care was named after them.

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