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## Measuring Matter: Mass, Volume, and Density

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**Measuring Matter: Mass, Volume, and Density**2 10/13/2014**Mass, Volume & Density**Questions Vocabulary words Formulas Main Ideas Possible Test Questions Notes Notes Notes Notes Notes Notes Notes Notes Notes Notes Summary of the notes and information learned**Today’s Warmup #1Intro to Measuring MatterDensity, Mass,**Volume**Today’s Warmup #2**This picture will NOT match our density column! • Liquid Density Column: • Work in two teams (I will assign.) • Small lab groups of 2-3 per material • Team with best result wins candy for all of their team members! • Record all data in lab-books**Density Column**• Materials Needed Per Large Group (entire class in two large groups) • graduated cylinder (100ml) • (10 ml) of each of the following (small groups of 2-3: one material/group) • water (red) • corn syrup (clear) • dish soap (green) • isopropyl alcohol (blue) • vegetable oil (yellow) • Procedure • Measure out 10 ml of your material • Find and record the density of your material in your lab-book • Gather with the rest of your large group; record density of all substances in your lab-book • Determine correct order to pour density column; record order in lab-book • Create density column using your data; pour slowly and carefully down side of 100 ml graduated cylinder for best results**Density Column- Instructions**• In your lab-book: • Was your group correct in its calculations?!? • Describe and explain what you see. Obviously the word “density” should be a part of your explanation.**Mass & Volume**• What is mass? • How do we measure mass? • Is it ever difficult to measure mass? When? • What is volume? • How do we measure volume? • Is it ever difficult to measure volume? When? • How would we measure the volume of an irregularly shaped object?**Water Displacement Chamber**• With simple shapes (like a cube) you can measure the outer surface and calculate volume (LxWxH). But what of you have an irregular object??? • What can we do to find the volume of an oddly-shaped rubber monkey-man???**Water Displacement Chamber**• There are two ways to calculate volume: • Direct measurement of surface area (LxWxH) • Water displacement • We can measure the amount of water an object displaces (pushes out of the way) to find its volume • What if our object floats? What do we have to do? 1 cm3 = 1 ml**Properties of solids/liquids- density**• Can we calculate the density of our irregular object? • Density is a property that describes the relationship between the volume and mass of an object • Density is amount of mass per volume (D = m/v) • Commonly expressed in g/cm3 D = m/v Mass (g) Density (g/cm3) Volume (cm3)**Manipulating the Density formula**The “magic triangle” way! D=m/v Place your finger onwhatever you want to find. D=? D=m/v m=? m=Dv v=? v=m/D m D v**Manipulating the Density formula**The “real math” way! D=m/v m=? Multiply both sides by v v x D = m/v x v/1 (v cancels out leaving only m) v x D = m/1 m = v x D**Manipulating the Density formula**The “real math” way! D=m/v v=? Multiply both sides by v v x D = m/v x v/1 (v cancels out leaving only m) v x D = m Divide both sides by D (D cancels out on left) v = m/D**Manipulating the Density formula**Let’s practice: density = 13.5 g/mLmass = 151 gramsvolume = ? density = ?mass = 325 gramsvolume = 375 mL density = 1.25 g/mLmass = ?volume = 45.0 mL 11.2 mL .867 g/mL 56.3 g**Properties of solids/liquids- density**• Density describes how tightly packed the atoms or molecules are in a substance • 1 kilogram of lead takes up much less space (volume) than 1 kilogram of Styrofoam D = m/v • What about the density of liquids? • Generally density decreases from solid to liquid to gas… What about water?!? Mass (g) Density (g/cm3) Volume (cm3)**Properties of solids/liquids- density**• Working with your lab partner: find the density of your object/cube (using both methods discussed) and record in you lab-book • Be sure to use proper units! • Questions: • Are both answers the same? • Should they be? • If they are, why? If they are not, why not?**Properties of solids/liquids- density**• Does density change with the size of a sample being measured? • Let’s find out. • No. Density is an intensive property (like temperature and color). It is the same for a given material regardless of the amount. 8.9 g/cm3**Buoyancy of fluids**• Have you ever noticed how easy it is to lift someone in the swimming pool? • Why is that the case? • How can an aircraft carrier made of 97,000 TONS of steel float???**The big boat build-off**• You and your lab partner have 10 minutes to construct a boat made out of aluminum foil. • The team whose boat holds the highest number of pennieswithout sinking willbe declared thewinners!**The big boat build-off**• What keeps the aluminum foil from sinking? • What shape allowed the greatest number of pennies to float? Why • Is there a maximum mass or size that a ship can be built? Why or why not?**Buoyancy of fluids**• The upward force that liquids exerts against gravity is called buoyancy. • Buoyancy- a measure of the upward pressure a fluid exerts on an object**Archimedes’ Principle**• 3rd century BC Greek mathematician/scientist • He found that the force exerted on an object is equal to the weight of the fluid displaced by the object… So if a aircraft carrier displaces an amount of water that weighs more than the carrier… it will float!**Archimedes’ Principle**• “Eureka!”(I’ve found it!)**Buoyancy and gases**• How does a hot-air balloon float? A helium balloon? • The principle of buoyancy also applies to gases. • Charles’ Law (Jacques Charles- 1787): The volume of a gas is relative to its temperature. The volume of a gas increases with increasing temperature and decreases with decreasing temperature.**Pressure and gases**• Why do your ears pop when you fly in a plane or drive up a mountain? • Pressure- the outward force exerted by molecules of gas: SI unit pascal (Pa); English unit pounds per sq. inch (psi)**Pressure and gases**• How are pressure and volume related? • What if we take the same amount of air (same # of molecules) and put it in a 60” beach ball and a 30” basketball?**Pressure and gases**• Boyle’s Law (Robert Boyle 1662): • As the pressure of a gas increases, its volume decreases proportionately. As the pressure of a gas decreases, it’s volume increases proportionately. P1V1 = P2V2 New pressure Initial pressure Initial volume New volume**Pressure and fluids**• Bernoulli’s Principle: The pressure in a fluid decreases as the fluid’s velocity increases. (hair dryer demo)**Pressure and fluids**• Pascal’s Principle: When there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. (glass bottle demo)**Viscosity- liquids & gases**• Viscosity- a measure of a materials resistance to flow… water is LESS viscous than maple syrup • Large, bumpy molecules increase viscosity… more friction means more resistance to flow • For liquids- as temperature increases, viscosity decreases. Increasing energy means molecules can slide past each other easier; loose bonds are broken. • For gases- increasing temperature increases viscosity!**Oobleck… solid? liquid?**We use the term “viscosity” to describe the resistance of a liquid to flow. Water, which has a low viscosity, flows easily. Honey, at room temperature, has a higher viscosity and flows more slowly than water. But if you warm honey up, its viscosity drops, and it flows more easily.**Oobleck… solid? liquid?**Most fluids behave like water and honey, in that their viscosity depends only on temperature. We call such fluids “Newtonian,” since their behavior was first described by Isaac Newton (when he wasn’t discovering the laws of gravity or developing calculus).**Oobleck… solid? liquid?**The cornstarch mixture, Oobleck, is called “non-Newtonian” since its viscosity also depends on the amount of force applied to the liquid or how fast an object is moving through the liquid.**Final Assessment**• Density Quiz • You may use: • Calculator • Formula sheet**Mass, Volume & Density**Questions Vocabulary words Formulas Main Ideas Possible Test Questions Notes Notes Notes Notes Notes Notes Notes Notes Notes Notes Summary of the notes and information learned