Introduction: This experiment was done to carry out an investigation to testthe

Question

Introduction:

This experiment was done to carry out an investigation to testthe affect of temperature on the viscosity of engine oil.

Viscosity is the internal property of a fluid that resists theforce tending to cause the fluid such as liquids and gases toflow. In liquids, both molecular interchange and cohesioncontribute to viscosity. Cohesion refers to the cohesive forcewhich is a physical property of a substance, caused by theintermolecular attraction between like-molecules within that bodyor substance. Alternatively, molecular interchange is the rate atwhich molecules of that substance move.

Viscosityis measured by the following formula:

where,

delta p = difference in density between the sphere and theliquid

g = acceleration of gravity

a = radius of sphere

v = velocity = d/t = (distance spherefalls)/(time of it takes to fall)

Pascal-second (symbol: Pa·s) is the SI unit of viscosity,it is equivalent to newton-second per squaremetre (N·s m–2).

Thermal energy is the internal energy of an object. It consistsof kinetic and potential energy. When these two types of energieschange the internal energy of the object changes consequentlychanging the thermal energy. Temperature is the measure ofthe average kinetic energy of the molecules of a substance. Thegreater the kinetic energy the higher the temperature. Thus whenthe thermal energy increases the temperature increases too.

When particles receive more thermal energy (i.e.their temperature increases) they move more rapidly and become moremobile. As a result, the attractive binding energy betweenlike-molecules is lessened and therefore the cohesive force isreduced. In contrast, the rate of molecular interchangesimultaneously increases when the temperature of that fluid rises.The former effect tends to cause a decrease of shear stress, whilethe latter causes it to increase. The net result is that liquidsshow a reduction in viscosity with increasing temperature.

shear stress is a stress state in which the shape of a materialtends to change (usually by "sliding" forces -- torque bytransversely-acting forces) without any particular change involume.

In this experiment, the heat is conducted to the engine oilbeing heated using the hot plate as a source of heat. This type ofconduction is direct contact and is referred to as thermalconductivity.  

When an object changes medium (i.e. loose bead changing from airto engine oil medium), its velocity changes (i.e. either accelerateor decelerate).This happens because the object encounter adifferent resistance. At a particular speed, the drag forceproduced by the new medium will equal the object's weight(mg) (i.e. mass × gravity). At this instant, theobject stops to accelerate altogether and continues falling at aconstant speed called terminal velocity.

Explanation / Answer

Hi,

           Your introduction is good.

            I hope that no changes are necessary.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.