1. Chapter 11 Surface tension and viscosity
Google-youtube: How to demonstrate surface-tension property of water DIY Garage Oil Basics AOL Autos Motor oil: Understanding the numbers

2. Chapter 11 Surface Tension
Surface tension is the energy required to increase the surface area. Forces surround molecules within a liquid (such as water) but NOT at the surface. Surface tension arises from these top sideways forces. Surface tension can cause a paperclip to seem to “float” on water which in reality is a water- paper clip contact failure. Detergent companies add surfactants to maximize water – object contact .

3. Chapter 11 Surface Tension
Like dissolves like: Notice that both detergents have an end that is non-polar (to dissolve non-polar oils) and an ionic end to interact with water( a polar solvent ).

4. Chapter 11 viscosity
The rate of fall of metal spheres measures the oil viscosity. Engine oil viscosity (flow resistance)depends on temperature. SAE 50 oil (highest viscosity) would be used at high temperatures; SAE 20 would be used at low temperatures.

5. Chapter 11 viscosity
Multi-grade, synthetic oil is probably the best engine oil available. Multi-grade means low viscosity at low temperatures (“SAE 10W”)and high viscosities at high temperatures(“SAE 30”). ALWAYS BUY THE BEST ENGINE OIL.