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Expanding Science Labs into Science Projects

LAB III: MASS, VOLUME, AND DENSITY OF LIQUIDS

Problem: What is the density of some common liquids?

NOTE: DO NOT START YOUR EXPERIMENT UNTIL EACH PERSON IN Y0UR GROUP HAS READ THE BACKGROUND AND ANSWERED THE BACKGROUND QUESTIONS.

Background and Inquiry: You are already familiar with density. Density can be calculated using the formula D=Mass/Volume. Volume of a liquid can easily be found using a graduated cylinder. To find the mass of the liquid you must first find the mass of the liquid and graduated cylinder together. To find the mass of the liquid alone subtract the mass of the graduated cylinder alone from the mass of the graduated cylinder with the liquid.

Many liquids have different densities. You already know oil is less dense than water. This causes oil to float on water. Other liquids that are less dense than water are alcohol, gasoline, and many soaps. Different types of soap can be used to break up fats and oils.

Background Questions:

1)The mass of an empty graduated cylinder is 70 grams. When it is filled with 50 ml of liquid it's mass 120 grams. What is the mass of just the liquid? What is the density of the liquid?

2) Oil does not mix with water. When an oil tanker spills oil the oil floats on the surface of the ocean. Why does oil float and not sink?

Hypothesis: In this lab you will calculate the density of three different liquids: water, oil and corn syrup. Discuss with your group what you might expect each of the densities to be and why.

Materials: Triple beam balance, beakers, graduated cylinder, water,corn oil, corn syrup

Procedure:

IMPORTANT: Only fill the labeled graduated cylinders with the designated liquid. Only put water in the graduated cylinder that is labeled for water.

Use the following steps as a working guide Then complete the Tables shown below.

Find the Density of water

1)Find the mass of the empty graduated cylinder that has the label "water".. Mass of cylinder = _____grams.

2)Fill the graduated cylinder with water to the 50 ml. level. The water now has a Volume=_____ cu.cm.

3) Find the mass of the water and graduated cylinder. The mass is = ______ grams.

4) Find the mass of just the water (#3-#1). Mass of just water = ______ grams.

5)Find the density of water at room temperature. Density= Mass / Volume. D= _____g/cu.cm.

Note: Be sure and return the corn oil and corn syrup to their original containers after the experiment is complete

Find the Density of corn syrup

1)Find the mass of the empty graduated cylinder that has the label "corn syrup".. Mass = _____grams.

2)Fill the graduated cylinder with corn syrup to the 50 ml. level. The corn syrup now has a Volume=_____ cu.cm.

3) Find the mass of the corn syrup and graduated cylinder. The mass is = ______ grams.

4) Find the mass of just the corn syrup (#3-#1). Mass of just corn syrup = ______ grams.

5)Find the density of corn syrup at room temperature. Density= Mass / Volume. D= _____g/cu.cm.

Find the Density of corn oil

1)Find the mass of the empty graduated cylinder that has the label "corn oil".. Mass = _____grams.

2)Fill the graduated cylinder with corn oil to the 50 ml. level. The oil now has a Volume=_____ cu.cm.

3) Find the mass of the oil and graduated cylinder. The mass is = ______ grams.

4) Find the mass of just the oil (#3-#1). Mass of just corn oil= ______ grams.

5)Find the density of oil at room temperature. Density= Mass / Volume. D= _____g/cu.cm.

Results:

Complete the following table:
Table I.

 Water Corn Oil Corn Syrup 1) Mass of empty graduated cylinder 2) Mass of graduated cylinder and 50 ml of liquid 3) Mass of 50 ml liquid alone (subtract 2-1=) 4) Density of Liquid

Part II. Complete the following table using water. Measure mass for each volume using the triple beam balance to the nearest tenth of a gram.

Table II.

 Volume in ml. Mass in grams 0 10 20 30 40 50

Make a graph of your results. Mass on the vertical axis (y-axis) and Volume on the horizontal axis (x-axis). Find the slope of the line. Use your math book to find out what slope is if you are not sure!

Table III. Complete the following table using corn oil. Measure mass for each volume using the triple beam balance to the nearest tenth of a gram.

 Volume in ml. Mass in grams 0 10 20 30 40 50

Make a graph of your results. Mass on the vertical axis (y-axis) and Volume on the horizontal axis (x-axis). Find the slope of the line. Use your math book to find out what slope is if you are not sure!

Discussion:

1) Compare the densities of the three liquids in this experiment.
1) Is it possible to estimate densities of liquids in a container by holding them in your hand?Explain?
2) What is the relationship between the slope of your two graphs and the density of the liquid used.

Applications:
Design an experiment using just the liquids and a graduated cylinder that would demonstrate the different densities of the liquids.See page 21 of the Glencoe textbook for a hint.