Volume and Density LabName ____Answer Key______
7th Grade Environmental Science
Mrs. KrempaName______
Date & Section ______
PURPOSE: The purpose of this lab is to calculate the volume and density of a solid object.
PROCEDURE: You must find the volume of 9 objects by measuring the amount of water displaced
when the object is submerged in a beaker or graduated cylinder.
1. Fill the beaker or cylinder with enough water cover the object completely.
Initial (starting)volume is the first reading without anything in the cylinder/beaker.
2. Carefully put the object in the cylinder/beaker, making sure that the water covers ALL ofit.
This is your Final (end) volume.
3. Subtract your initial volume from your final volume to get your Sample (object, thing) volume.
Completethe table below with your measurements. * Be sure to include all units!*
Sample / Initial Volume / Final Volume / Sample Volume1) / Aluminum rod / 24 mL (22 to 26)
2) / Paper Clip (pink) / .1 mL (.2)
3) / Large green rubber stopper / 60 mL (50 to 70)
4) / Copper weight with hook / 7 mL (6 to 8)
5) / Wood Block / 150 mL(140 to 160)
6) / Golf Ball / 45 mL (35 to 55)
7) / Small Black rubber stopper / 2.8 mL (2.6 to 3.0)
8) / Wood Screw / .6 mL (.4 to .8)
9) / Blue Bead / .2 mL (.1 or .3)
4. You can also find the volume of an object by measuring it. Use the formula to find
the volume of the box. (Use centimeters as your unit).
Volume = length x width x height
6cm x 2.4cm x 2.2cm
Volume = 31.68 cm3 (don’t forget units)
*Answer range from 27.25 cm3 to 35.07 cm3
5. Convert the volume of the box you just measured to milliliters.
31.68 mL (same exact answer as #4, but with mL, not cm3)
6. Remember that the density of an object can be calculated with the following equation:
Density (D) = Mass
Volume
Calculate the density of the following objects or liquids. Use your Mass Lab to find the mass, and be sure to include the correct units! Some masses are given.
Show your work below!
Work:
*Must have the work for at least two problems shown!!
D = M = 68.7 g = 2.86 g / mL
V 24 mL
D = M = 94.4 g = .67 g / mL
V 150 mL
ANALYSIS & CONCLUSIONS : Answer the following questions in full sentences. Be detailed!
If you need more room please continue on the back of this lab.
Watch your wording! No it, them or they.
Do NOT start with Because, or Yes, because…
1. What objects floated? Looking at the object’s density, why (or why not) does it makesense
that this object(s) were able to float?
The wood block was the only object that floated. It makes sense that the wood block floated because it’s density is less than 1, which means it will float in water.
2. Why was #5 in procedures (bottom of front page) a trick question? (technically speaking…)
#5 was a trick question because no conversion was needed. 1 mL = 1 cc, so your answer
was exactly the same number, just with different units.
3. Briefly explain how you find the volume of a solid. NOT (L x W x H), but what you actually
did in the procedures of the lab!
~ Filled beaker/graduated cylinder with enough water to cover object. Record volume.
~ Put object in beaker / graduated cylinder. Record volume.
~ Subtracted the two volumes to get the volume of the object.
4. List and explain at least three sources of error and how those problems could be fixed.
Source ___Splashing – splashing changes the initial volume___
Fix ___ Don’t splash! Carefully lower object.___
Source ___ Mis-reading the beaker / graduated cylinder___
Fix ___ Make sure you understand the scale you are reading.___
Source ___ Do the math wrong___
Fix ___ Make sure you record the numbers correctly and use a calculator if needed.___
**Other sources of error… estimating the beaker volume wrong, not reading at eye level,
not reading from the bottom of the meniscus… there are others…
*5. Challenge! How can you find the density of water? Calculate your answer and briefly
explain how you got it below. Use the density data table to record your numbers. There is equipment set upin the lab to help you. What could be the cause of the difference in your answer and the known density of water? Use the back of this sheet if you need more room! ~No calculations (work) shown? NO CREDIT!
1. Find the mass of the empty beaker
2. Find the mass of the beaker with water
3. Subtract the two to get the mass of the water
4. Look at the beaker to get the volume of the water
5. Plug the numbers into the Density equation
6. Answer should be very close to the actual density of water (which is 1 g/mL)
Why the difference? Why didn’t you get exactly 1 g/mL? You found the mass of two different beakers – even though the beakers are the same size made by the same company – chances are they do NOT have the exact same mass. You could have mis-read the triple beam balance. Did you zero the scale before you started? I tried to put exactly 30 ml of water in each, but maybe I didn’t… AND you had to estimate the volume in the beaker. What else?
Calculations:
D = M = 34.2 g = .98 g / mL
V 30 mL