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저작시기 2007.12 |등록일 2009.12.22 워드파일MS 워드 (docx) | 5페이지 | 가격 400원

소개글

When a charged body is brought near a razor blade gently placed on a water surface, the razor blade is repelled from the charged body. We decided to investigate how external electric fields affect the motion of materials when they are placed on a water surface.

목차

1. Introduction
2. Theoretical Backgrounds
3. Experiment
4. Discussion
5. Conclusion
6. Further Discussion

본문내용

5. Conclusion
The repulsive motion of a razor blade on water surface to a charged body can be observed and similar motion is observed for different materials that float on water. The main driving force of the repulsive motion is the surface tension gradient between two sides of an object due to the induced water surface curvature. In cases of very sharp objects such as needles, lots of electrons gather in a sharp region and thus increase electric attracting force and due to such objects’ geometry, surface tension is exerted on a very small length. Therefore electric force dominates surface tension gradient, so the object is attracted.

6. Further Discussion
In the previous discussion, we have ruled out water pressure as a possible candidate for the source of razor blades’ movement on water. However, considering the magnitude and direction of force due to water pressure on a tilted water surface, we concluded that water pressure would dominate other forces, mainly surface tension, in most situations. Since water pressure exerts normal to water surface, if water surface is tilted due to external electric field,
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