Why do some liquids flow more freely than others?
Liquids vary in their viscosity (resistance to flow).
A definition of viscosity; “Viscosity is a measure of a fluid's resistance to flow. It describes the internal friction of a moving fluid. A fluid with large viscosity resists motion because its molecular makeup gives it a lot of internal friction. A fluid with low viscosity flows easily because its molecular makeup results in very little friction when it is in motion. Gases also have viscosity, although it is a little harder to notice it in ordinary circumstances.” Some liquids flow more easily than others do. For example, honey is very “thick” and flows very slowly. Water is thin and flows very quickly. So honey is more viscous than water. Liquids that are made up of small molecules have a low viscosity and liquids with long chain molecules (such as plastics) have a much higher viscosity. For my experiment I am going to test the viscosity of some solutions which I can then analyse to test my hypothesis, so I will be measuring and comparing viscosities. Results for different liquids can be linked to science ideas about the structure and arrangement of particles within the liquids studied e.g carbon particles.
Hypothesis: the longer the carbon chain the higher the viscosity.
Risk assessment :
Goggles must be worn incase any of the liquids manages to get in the eyes. The hazards associated with every liquid used in these tests must be checked. For example, liquid hydrocarbons and alcohols are flammable (and many are harmful). No flames should be allowed in the laboratory when any of these are in use.
For the experiment I am going to use clamp a tile up at an angle and run different alcohols down it to investigate their velocity’s. The alcohols im going to test are methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol.
White tile- to release the liquid on and then time the distance it takes. Stopwatch- to time...
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