How to Calculate Density
How do we know the density of a substance? We can’t see the molecules inside a substance to know how dense it is. Instead we can calculate how dense something is. Remember, density is how much mass is in a certain space. Therefore…
Remembering Mass To get the density of an object you need to know its mass and its volume. Mass- the amount of matter in an object. To measure mass, we use a triple beam balance. Units for mass= grams
Unit with graduated cylinder-= mL Unit with displacement-= mL Remembering Volume Volume- the amount of space an object takes up. To measure the volume of a liquid, we use a graduated cylinder. To measure the volume of a solid, we calculate : L x W X H To measure the volume of an irregular solid we use volume displacement. Unit with graduated cylinder-= mL Unit with a ruler= cm3 Unit with displacement-= mL
Calculating Density Imagine you had a metal cube that has a mass of 20.0 grams and a volume 5.0 cm3. What is its density? D = M__ V D= 20.0 grams 5.0 cm3 D= 4.0 D= 4.0 _g_ cm3 SHOW ALL WORK!
You try… The mass of an object is 10.0 grams and its volume is 4.0mL. What is its density? D = M__ V D= 10.0 grams 4.0 mL D= 2.5 D= 2.5 _g_ mL SHOW ALL WORK!
The Density of Water THE DENSITY OF WATER IS 1.0! SHOW ALL WORK! The mass of water is 10.0 grams and its volume is 10.0mL. What is its density? D = M__ V D= 10.0 grams 10.0 mL D= 1.0 D= 1.0 _g_ mL THE DENSITY OF WATER IS 1.0! SHOW ALL WORK!
Will it sink or float? If an object has a density greater than water (1.0), it will sink. If an object has a density less than water (1.0), it will float. Less than 1.0 More than 1.0
Liquid Layers If you pour together liquids that don’t mix and have different densities, they will form liquid layers. The liquid with the highest density will be on the bottom. The liquid with the lowest density will be on the top.
Check out this picture 3 5 6 10 Which layer has the highest density? Which layer has the lowest density? Imagine that the liquids have the following densities: 10.0 g/cm3 3.0 g/cm3 6.0 g/cm3 5.0 g/cm3 Which number would go with which layer? 10 6 5 3