How compact is the material? Density How compact is the material?

Density is the measure of the “compactness” of a material How close the atoms or molecules are to each other More than“heaviness”- density includes how much space an object takes up! All substances have density including liquids, solids, and gases Bread slice and compacted bread in large flask of water

“Compactness” Hot air balloon - Describe how a hot air balloon works. Defend your argument.

Density Density describes how much mass is in a given volume of a material.

Mass is the amount of matter in an object (usually measured in grams) Volume is the amount of space an object takes up (usually measured in ml or cm3)

Density Equation D = m v

Word problems Given: mass = 1500 g; volume = 1700 mL Equation: D = m/v A solid wax candle has a volume of 1,700 mL. The candle has a mass of 1.5 kg (1,500 g). What is the density of the candle? Given: mass = 1500 g; volume = 1700 mL Equation: D = m/v Solve: 1,500 g ÷ 1,700 mL = 0.8823529 g/mL = .88 g/mL

increase decrease What do you think? If the volume stays the same and the mass increases . . . the density will If the mass stays the same and the volume increases . . . The density will increase decrease What do you think?

For liquids use units of grams per milliliter (g/mL) Units for density The units used for density depend on whether the substance is solid or liquid. For liquids use units of grams per milliliter (g/mL) For solids use density in units of g/cm3 or kg/m3.

Density of common materials Liquids tend to be less dense than solids of the same material. Ex. solder

Density of common materials Water is an exception to this rule. The density of solid water (ice) is less than the density of liquid water.