Density Notes Science Tennessee SPI Objective: Apply an equation to determine the density of an object based on its mass and volume. Check for Understanding Calculate the density of various objects. Essential Question(s) 1) What is density? 2) What is mass, and how do I measure it? 3) What is volume, and how do I measure it? 4) How do I calculate density? 5) How do I multiply and divide with decimals without a calculator?

SPI 0807.9.7 Notes Density Demonstration: What is density? Science What is density? Density is the amount of matter (mass) you have crammed in a given space (volume) Reminder: mass is how much matter is in an object The unit for mass is grams (mg or g or kg) Reminder: volume is how much space it takes up (size) Unit for solid volume is cubic meters (cm3 or m3 or km3) Unit for liquid volume is liters (mL or L or kL) Demonstration: Demonstrate with wadded up paper in a trash can Can about 1/4 full-explain that the density is low Can about ¾ full…explain that the density has increased Explain-density can be increased by putting in more paper

SPI 0807.9.7 Density Notes Density Example: Science Density Example: Here are two objects that are the same size. (1) Bowling Ball and (2) Soccer Ball One of these objects contains more matter (mass). With two same-sized objects like this (volume), the object with more mass has greater density than the other object. Less Dense More Dense

Example: Oil floats on top of water Density in Liquids Lower density liquids will float on top Higher density liquids with sink downward Designation Substance Density Liquid 01 Water 1.0 g/mL Liquid 02 Liquid Mercury 13.6 g/mL Liquid 03 Turpentine 0.8 g/mL Example: Oil floats on top of water 1) Identify which liquids would occupy levels A, B, and C according to their density. Level C Level B Level A SPI 0807.9.7 (Density) ANSWERS Turpentine (0.8 g/mL) Water (1.0 g/mL) Mercury (13.6 g/mL)

View this YouTube Video Clip: Link: 7-Layer Density Column SPI 0807.9.7 Density Notes Science Density In Liquids Lower density liquids float on top of liquids with higher density Higher density liquids will sink below lower density liquids View this YouTube Video Clip: Link: 7-Layer Density Column

or or Calculating density divide the mass by the volume of the object Density Formula Density = mass divided by volume M V D = D= M V or or Density = volume mass Dividend is the number being divided. In this case it will be number for mass. Math Vocab: Dividend and Divisor Divisor is a number that divides into another number In this case…it will be the number for volume. Memory Trick Soon you will get your first driver’s license (scary!) The place where you receive your driver’s permit is called the DMV (Department of Motor Vehicles) Think of DMV for density D= M V

Solve the Density Problem Shown Below Go ahead and use a calculator (for now) Round to the tenths place 1) Calculate the density of an object with a mass of 25g and a volume of 10cm3 Example: 25 (mass) divided by 10 (volume) Units… g/cm3 Density= 10 25 Answer 25 g ÷ 10 cm3 = 2.5 g/cm3 Don't Forget Your Units! Example: grams/centimeter cubed Written like this…g/cm3

Solve the Density Problem Shown Below Go ahead and use a calculator (for now) Round to the hundredths place 2) Calculate the density of an object with a mass of 45kg and a volume of 43m3 Example: 45 (mass) divided by 43 (volume) Units… kg/m3 Density= 43 45 Answer 45 kg ÷ 43 m3 = 1.05 kg/m3 Don't Forget Your Units! Example: kilograms/meters cubed Written like this…kg/m3

Solve the Density Problem Shown Below Go ahead and use a calculator (for now) Round to the hundredths place 3) Calculate the density of an object with a mass of 350g and a volume of 95cm3 Example: 350 (mass) divided by 95 (volume) Units… g/cm3 Density= 95 350 Answer 350 g ÷ 95 cm3 = 3.68 g/cm3 Don't Forget Your Units! Example: grams/centimeters cubed Written like this…g/cm3

SPI 0807.9.7 Density Notes 4 g/cm3 2.71 g/cm3 3.6 g/cm3 4.6 g/cm3 Which cube below has the GREATEST density? Again…go ahead and use a calculator (for now) Notes Science Mass: 12g Volume: 3cm3 Mass: 19g Volume: 7cm3 (A) (B) 4 g/cm3 2.71 g/cm3 Mass: 11g Volume: 3cm3 Mass: 23g Volume: 5cm3 (C) (D) 3.6 g/cm3 4.6 g/cm3

Density = Mass divided by volume Volume = Density divides Mass SPI 0807.9.7 Density Notes Science Note: The density formula can be rearranged to find the mass or volume. Density = Mass divided by volume M V D= or Mass = Volume x Density m = V x D or M D V= Volume = Density divides Mass or Memory Trick: DMV to MVD to VDM A) Start with DMV for density B) Move the first letter (D) to the end C) Now you have MVD for mass (think M for multiply!) D) Move the first letter (M) to the end E) Now you have VDM for volume

1) DMV 2) MVD 3) VDM SPI 0807.9.7 Density Science Notes Memory Trick: DMV to MVD to VDM Now let’s practice this with the small dry-erase boards 1) DMV Question: What does DMV stand for? 2) MVD Question: What does MVD stand for? Remember: Think M for multiply! 3) VDM Question: What does VDM stand for?