Sci-ber Text - 7th Grade

Matter - Fill It Up!

Volume is a measure of the amount of space that something takes up.

Volume can be measured in the following ways.

If an object is rectangular, the length, width and height can be measured directly with a metric ruler. The three numbers multiplied together give the volume in cubic centimeters.
For irregularly shaped solids, water displacement can be used. The volume of a certain amount of water in a graduated cylinder or other measuring device is first measured. The object is dropped in. The change in water level is its volume.
If an overflow jar is available, the jar is filled; a graduated cylinder is placed under the spout, the object is dropped in and the overflow is measured.
The volume of containers can be measured indirectly by filling them with water, then pouring the liquid into a graduated cylinder or beaker for measurement.

Useful hints for measuring volume:

The smaller the graduations on the measuring device the more accurate your measurement will be. A milliliter is the same amount of volume as a cubic centimeter.
The volume of air in sand can be calculated by adding 40 ml of water to 40 ml of dry sand. The water will fill the air spaces in the sand and the top surface will be at about 65 ml. Since it would have been 80 ml without the air, the air must take up 15 ml of the sand. By dividing the volume of air by the volume of dry sand, the percentage of air in sand is found.

Question:
Once you find out how to measure mass and volume, can you determine how much air is in sand.

Hypothesis:
Write your own idea about how you can find out how much air is in sand.

Materials:

Small rock
Marble
Wood block
Baby food jar or any small container
Two100- mL graduated cylinders
Ruler
sand
A-50 mL beaker
A-250 mL beaker

Procedure:

Use the ruler to directly measure the length, width, and height measurements to find the volume of the wood block.
- Be sure to use centimeters (cm) so that the volume measurements will be easy to compare with the fluid volume measurements.
- Remember that the volume of any box shape is l * w * h; or length * width * height.
Use the graduated cylinder and the water displacement method for finding the volume of the marble.
- The amount of water you start with does not matter; just leave room for it to rise.
- Record the starting volume of water.
- Drop the marble into the graduated cylinder. To reduce the amount of splash and to avoid breaking the cylinder, tilt the cylinder on an angle and slide the marble down the side into the water.
- Record this final volume in the data below.
- Subtract the beginning volume from the final volume. The difference is the volume of the marble!
Repeat the same steps above to find the volume of the small rock. Record your data as you go.
Try the water displacement method to find the volume of the marble again, this time using a beaker instead of the graduated cylinder. Repeat the same steps above.
Use direct measurement to find the volume of the baby food jar:
- Fill the jar with water.
- Pour the volume of water into a graduated cylinder, and record it's volume.
- If the jar can hold more water than the graduated cylinder, place as much water as you can measure into the cylinder, record the volume, pour the water into the sink, and measure the rest of the water in the jar. Add these volumes together for a final volume measurement.
Find the volume of air in sand.
- Measure 40 mL of sand into the 50 mL beaker.
- Measure 40 mL of water into a graduated cylinder.
- Carefully pour the sand into the water in the graduated cylinder. Try not to get any sand stuck on the sides.
- Allow the sand to completely submerge in the water. Make sure there are no air bubbles left!
- The total volume of the sand and water should be 80 mL, since you added 40 mL of one into 40 mL of the other. Record the final volume of the sand/water mixture. If there is a difference between the final volume and 80 mL, this difference is the volume of air in the sand!

Safety concerns: Be sure to follow all glassware safety rules that are specified by your teacher in all general laboratory experiences. Because graduated cylinders may break, make sure the rocks are not too big to fit in the cylanders. Tilt the graduated cylinders of an angle and slide the marbles or pebbles down the side for the water displacement method. This will reduce the amount of spash produced and reduce the chances of the graduated cylander breaking. Remember that you should not put a stopper into any flask unless given direct instruction to do so by your teacher.

Data:

1. Wood block:

length__________ cm
width__________ cm
height__________ cm
volume (l*w*h) = __________ cm³

2. Marble (using graduate):

final volume of water__________ mL
beginning volume of water__________ mL
subtract beginning from final
volume =__________ mL

3. Rock (using graduate):

final volume of water__________ mL
beginning volume of water__________ mL
subtract beginning from final
volume =__________ mL

4. Marble (using beaker):

final volume of water__________ mL
beginning volume of water__________ mL
subtract beginning from final
volume =__________ mL

5. Baby food jar =__________ mL

6. Volume of air in the sand:

beginning: sand + water = _____________mL
final volume = _____________ mL
subtract final from beginning
difference = _____________ mL of air in the sand

Analysis:

Which had the greater volume - the marble or the rock?
Which had the greater volume - the wood block or the baby food jar?
How close were the volume measurements for the marble using the graduated cylinder and the beaker in the water displacement method? Which method do you think is most accurate?
What percentage of the sand is air? Divide air space (from #5) by the amount of sand (40 mL) and multiply by 100%.
What is the relationship between mL and cubic centimeters?
Which volume measurement method would you use to find the volume of:
- a glass of milk?
- a book?
- a pencil?
What are two things that you learned from this lab?
Which method was the easiest to use?
Which was the most difficult method to use?