Investigation on whether Rubber obeys Hooke's Rule
Investigation on whether Rubber obeys Hooke's Rule Plan Introduction Hooke's Rule states that extension of a material is proportional to the tension force applied to it unless the elastic limit is reached, which is the point at which the material no longer obeys Hooke's Rule. There are only a few materials that obey this rule. In this investigation, we will find out whether rubber obeys Hooke's Rule. We will measure in detail the way in which the extension of a rubber band depends on the tension in the band. This will be done by applying various amounts of weights, as it is a continual variation. Hooke's Rule = F = ke * F = Force in Newtons * k = Spring constant * e = Extension in Centimetres Rubber is a natural polymer which is made up of long chains of molecules which are bent back and forth with weak forces acting between them. As the rubber band is stretched, molecules straighten out and allow the rubber band to become larger. Eventually, as the molecules become fully stretched, the long chains will become parallel to each other and can stretch up to ten times its original length. Extra force will make the rubber band break. If the rubber is not stretched to breaking, once the force is removed the molecules tend to curl back again into their original position because of the attraction and cross-links between adjacent molecules. The return is elastic. Hypothesis I
Properties of Waves.
Properties of Waves There are many different waves including water, sound, light and radio waves. All waves have the same range of properties, they can all be reflected, refracted, totally internally reflected, diffracted or interfere with each other. Waves are repeated oscillations (vibrations) which transfer energy from one place to another. Sound energy in the atmosphere is transferred by the oscillation of air molecules. Movement energy in water waves is transferred by the oscillation of water molecules. Amplitude is the measure of the energy carried by it. Frequency (f) is the number of complete wave cycles per second and is measured in Hertz (Hz). Wavelength (?) is the distance between two successive peaks or troughs and is measured in metres, m. Reflection Light waves travel in straight lines but reflecting them using mirrors can alter their direction. Reflection is the bouncing off of any type of wave from a surface. Reflection can be used to guide a laser past obstacles to a receiver. Shiny surfaces such as mirrors are smooth so reflect all light strongly as all the waves pass in one direction only. Rough surfaces look dull as they reflect light in many different directions causing it to scatter. This is called diffuse reflection. If light waves are reflected, the colour of the surface affects the colour of the reflected ray. Concave surfaces are used