Foundations of Physical ScienceWorkshop: Density of Fluids

Density of FluidsCPO Science

Key QuestionsCan you create a stack of liquids?

How do you find the density of a liquid?

Does the density of a liquid change as its temperature changes?

Overview Calculate the Density of various fluids

Construct Density column

Use a density column to predict the density of a solid

What is Density? Ratio of mass to volume-mass/vol.

Usually decreases as temperature increases

Water is a notable exception – it takes up less space in its liquid form than in its solid form; result – Ice (solid water) floats in liquid water

Measuring Density Calculate mass per unit volume for

each of the sample liquids

Record the density of each liquid

Rank the liquids according to density

Creating a Density Column A stack of liquids

Can you make one with your sample liquids?

What order would be best when pouring them into the cylinder?

Using a Density Column How can we use the stack

of liquids to estimate the density of objects?

Drop objects in cylinder and observe – Make Predictions First

How can we use this information?

Observations The object sinks all the way to the

bottom of the stack

The object floats on top of the stack

The object is suspended somewhere in the middle of the stack, between 2 layers

How did your predictions stack up?

Predicting Density The rubber stopper is suspended at the

border between glycerin and water

Its density must be less than that of glycerin and greater than that of water

.99 g/ml < density of the rubber stopper < 1.21 g/ml

Comparing Predicted and

Measured Values Stopper Mass – 4.2 g

Stopper Volume – 3.5 ml

.99 g/ml < density of the rubber stopper < 1.21 g/ml

4.2 g/3.5 ml = 1.2 g/ml BINGO!