Chapter 17 Notes

Properties of Solids Density- describes the relationship b/t mass and volume of homogenous material- tells how tightly molecules are “packed” Formula: D=m/v What are the units of density? Density stays the same no matter how large or small the sample is Heterogenous materials may not have the same density throughout

Other properties Hardness-resistance to scratching Elasticity-ability to stretch then return to original shape Brittleness-tendency to shatter on impact Malleability- ability to be pounded into sheets Tensile strength- measures how much tension a material can withstand without breaking

Density of Fluids Fluid- matter with the ability to flow (applies to gases too) How can a liquid form of the same material be less dense than the solid form? How does temperature affect density of solids? Why is ice less dense than liquid water? What would happen if ice became more dense than water?

Buoyancy The measure of the upward force a fluid exerts on an object Archimedes principle- the force exerted on the object is = to the weight of fluid displaced by the object

Sink or float? If buoyant force of fluid is greater than weight of object-object floats If buoyant force of fluid is less than weight of object- object sinks If forces are = will stay in place (neutral buoyancy Why is neutral buoyancy necessary for scuba divers?

Does shape matter? Yes, because the shape may displace more water. How can steel boats float, and steel cubes sink?

Viscosity Material’s resistance to flow Which has a higher viscosity: maple syrup or water? Why is viscosity important? Viscosity is determined by the shape and surface of molecules (friction)

Temperature and viscosity As temp increases liquids usually become less viscous Gases become MORE viscous with increasing temperature Why?