3B Scientific Device for Archimedes' Principle User Manual
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3B SCIENTIFIC
Device for Archimedes' Principle U40875
Operating instructions
04/08 ALF
®
PHYSICS
1 Handle
2 Bucket
3 Cylinder
1. Description
The device for Archimedes' Principle is used to
demonstrate Archimedes' Principle of buoyancy in
liquids. It can also be used to determine the density of an unknown fluid.
It consists of a bucket with a handle and a hook, as
well as a precisely fitted solid cylinder with a ring.
There are division marks on both the cylinder and
the bucket which allow the user to perform experiments with different volumes. Each division
mark represents one quarter of the total volume.
2. Basic principles
According to Archimedes' Principle, if an object is
immersed in a fluid, the force F
exerted on the
B
object by the fluid is equal to the weight of the
fluid F
displaced by the object, FB = FW.
W
Archimedes' Principle is valid in fluids as well as in
gases.
Since the volume of fluid V
is just equal to the volume of the object V
mass of fluid m
object V
m
multiplied by the density of the fluid ρ.
K
= ρ VK (1)
F
displaced is the volume of the
F
The weight of the displaced fluid F
displaced by the object
F
is this mass mF
W
the
K
multiplied by the acceleration due to gravity g.
mgF
(2)
FW
Therefore the buoyant force F
is given by the fol-
B
lowing formula
F
= ρ g VK (3)
B
The density ρ of an unknown fluid can therefore be
calculated by the formula:
F
B
=ρ (4)
V
1
3. Technical data
VoIume of cylinder: approx. 100 cm3
Mass of cylinder: approx. 120 g
Volume of bucket: approx. 100 ml
Dimensions: approx. 55x55x 55 mm
3
Net weight: approx. 150 g
4. Operation
4.1 Verification of Archimedes' Principle
Additionally required:
1 Dynamometer 250 g / 2,5 N U40810
1 Vessel with overflow U8411310
1 Beaker from U14210
1 Stand base U8611160
1 Steel rod, 750 mm U15003
1 Clamp with hook U13252
4.1.1 Experiment 1
• Set up the stand and suspend the dynamome-
ter from the hook.
• Insert the cylinder in the bucket to verify that
the volume of the cylinder is equal to the volume of the cylindrical cavity of the bucket.
• Attach the cylinder to the bucket and suspend
both from the dynamometer.
• Read and write down the weight.
• Fill the beaker with water and place it under
the cylinder.
• Lower the dynamometer until the cylinder is
immersed in the water up to the first division
mark.
• Read the new value for the weight.
• Fill the bucket with water to the first division
mark.
The dynamometer shows the initial value.
• In further steps lower the cylinder up to the
second division mark, than third and finally
until it is completely immersed in the water.
With each step pour the corresponding amount
of water into the bucket
Thus Archimedes' Principle is confirmed.
• Place the beaker next to the vessel with over-
flow so that the overflowing water can be collected.
• Lower the dynamometer until the cylinder is
completely immersed in the water. Collect the
overflowing water in the beaker.
• Read the new value on the dynamometer.
The difference between the two readings is the
buoyant force F
• Carefully pour the water from the beaker into
on the cylinder.
B
the bucket. Make sure no water is left in the
beaker.
The dynamometer displays the initial value. Thus
Archimedes' Principle is confirmed.
4.2 Determination of the density of an unknown fluid
Additionally required:
1 Ruler
• Use the ruler to measure the diameter d and
height h of the cylinder and calculate its volume (V = ¼ π d
• Determine the buoyant force F
2
h).
(ref. to point
A
4.1.2) with the unknown fluid in place of water.
• Use formula 4 to determine the density of the
unknown fluid.
4.1.2 Experiment 2
• Set up the stand and suspend the dynamome-
ter from the hook.
• Attach the cylinder to the bucket and suspend
both from the dynamometer.
• Read and write down the weight.
• Fill the vessel with overflow to such an extent
with water that it just stops to overflow.
3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com
Technical amendments are possible
© Copyright 2008 3B Scientific GmbH
Fig. 1 Experimental set-up
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