To learn ow to measure the density of different metal.
volume of the stone = difference between the levels
(about 260- 200 = 60mL)
INTRODUCTION - fill the blank for full credit
bank: matter, volume, space, density, property, lighter
DEnsity is the amount of __________ (mass) contained in a unit of ____________. Density is a physical ________
of matter. Consider 2 identical boxes, one filled with Styrofoam and one with stones. They both occupy the same amount of _________ so they have the same _________. But the box filled with Styrofoam is _________. We say
Styrofoam has a smaller __________.
PROCEDURE
you will need: one graduated cylinder having 1mL graduations
scale plate sensitive to 1g, 4 metal objetcts.
UNDERSTAND : 1mL (one milliliter ) is the same as 1 cm3. 1 cm3 is the space taken by the small cubes you played with.
step1: Fill the cylinder with water to V1= 30mL mark.
step2: The scales are fragile. be gentle. Turn on the scale. Don't put anything on it yet.
and wait to see 0 on the scale. If you don't get 0, push the zero button. weigh the metal object.
mo = ________g
step3: Carefully add the metal object to the graduated cylinder. Don't spill any water.
Measure new volume reached by the water. (with the object inside) V2 = _____mL (it has to be greater than 30mL of course)
Find the volume of the cylinder Vo = V2 - V1 = __________mL
Fill the TABLE below : for row 1 to 3
step4: repeat step1 to step3 for 3 other objects.
TABLE 1
| object1 | object2 | object3 | object4 | |
| (describe color) = | ________ | ____________ | _______________ | _______________ |
| mass mo (g) = | _______________ | _______________ | _______________ | _____________ |
| volume Vo (mL) | _______________ | _______________ | _______________ | ______________ |
| density (g/mL) = | _______________ | _______________ | _______________ | ______________ |
| Find the metal = | _______________ | _______________ | _______________ | ____________ |
ANALYSIS
1) Find the density of the material that makes up the object1: density = mo/Vo = __________g/mL (or g/cm3)
That means that if you cut out 1 unit cube, 1x1x1, or cm3 , out of the object, it mass is __________g.
Fill the TABLE 1 above row 4
2) Use this TABLE 2 below to find out what the object is made of. tSometime, it is hard to tell because the density of 2 different
metals are too close. In that case, use the fact that steel contains iron and should be attracted by a magnet.
Ask DL for a magnet. Then Fill the TABLE 1 above row 5.
TABLE 2. density of some metals
| aluminium | brass | copper | steel |
| 2.7 g/cm3 | varies . about 8.4 . | 8.9 g/cm3 | varies about 7.7. ... |
3) repeat 1) and 2) for the other objects.
GOING FURTHER for HW (try without hints. will be on your next QUIZ ?)
1) TO determine the density of a liquid , an empty graduated cylinder is placed on a balance, and its mass is found to be m= 120g. THe liquid is the added, up to V= 100cm3 mark. The cylinder is placed back of the balance. If the balance reads now M = 265g, what is the density of the liquid ?
hint: density = mass liquid / volume = (M-m) / V
2) A stone of mass 30 grams is placed in a measuring cylinder containing some water. The reading of the water level increases from 50cm3 to 60cm3. WHat is the density of the stone?
hint: density = mass of the stone/volume of the stone
3) A clump of metal weighing m= 351.4 g is dropped into a cylindrical container, causing the water level to rise
H= 1.1 cm. The radius of the base of the container is R= 3cm.
A) find the volume of water displaced. (use only H) You should remember how to find the volume of a cylinder.
\B) What is the density of the metal ?
hint: density = mass(g)/volume(cm3 )
C) Given the the table, and assuming the metal is pure, what is the metal ?
| Metal | DEnsity | Metal | DEnsity |
| Aluminum | 2.81 g/cm3 | Nickel | 8.89 g/cm3 |
| Copper | 8.97 g/cm3 | Platinum | 21.40 g/cm3 |
| Gold | 19.30 g/cm3 | Potassium | 0.86 g/cm3 |
| Lead | 11.30 g/cm3 | Silver | 10.50 g/cm3 |
| Lithium | 0.54 g/cm3 | Sodium | 0.97 g/cm3 |
4) When you put a rock into a container of water, it raises the water level H= 3cm. If the container is a rectangular prism
whose base measures 15cm x 15cm (width x length) . What is the volume of the rock ?
(find the volume of water displaced).
hint: volume of a box = W x L x H
5) You drop a solid glass ball into a cylinder with a radius of R= 6cm, raisin the water level H =1cm.
WHat is the volume of the glass ball ?
hint; volume of water displaced = base x height = пR2 x H
6) A fish tank 10 (W) by 14 (L) by 12 inches (H) high is the home of a large goldfish named columbia. She is taken out when her owner cleans the tank, and the water level in the tank drops h= 1/3 inch. What is Columbia's volume ?
7) Sherlock Holmes rushes to his chemistry lab, takes a mysterious medaillon from his case, and weighs it . It weighs 3088g.
Next, he found its volume. He pours water into a graduated glass container with a 10 by 10 square base, and records the water level, which is 53cm. He places the medaillon into the container and reads the new water level, 54.6 cm.
He enjoys a few minutes of mental calculations, then turns to Dr. Watson. "THis confirms my theory"
"Holmes, you amaze me. Is is gold ? questions the good doctors.
"If it has a density of 19.3 grams per cubic centimeter, it is gold "smiles Mr. Holmes.
What do you think? Is it gold ?
