In your lab notebook, create a data table like this one to record your measurements. Measure the buoyancy of each boat hull. Fill the sink, tub, bucket, or dishpan with some water. The water level should be deeper than the height of the boat hulls so that they are able to sink.
Procedure a Measure the three dimensions of each regular object, repeating each measurement at two or more places. Depending on the size of the measurement, use the ruler, vernier callipers or a micrometer. Teaching notes 1 Students will need to have studied density previously and be familiar with the density equation.
Either sets of units are generally acceptable, but all length measurements must use the same unit.
If both methods are used for the same sample, students could compare their two values and decide which one is more accurate.
In this experiment choose materials whose density is known to quite a high degree of accuracy, so that it is possible for students to perform a numerical comparison between the 'true' and measured values. They could be expected to find this data themselves or be provided with it.
A good comparison will express the difference between the measured value and the true value as a percentage of the true value. As an extension activity, you could ask students whether or not they can be confident that two different objects are made of the same material.
Ask them to find the density of a sheet of aluminium cooking foil and compare it to that of the solid aluminium block. This same approach could be taken with a block of wood and a piece of paper.
You might say "isn't paper made from wood? Alternatively, you could give the students a sample of an unknown material and then samples of known materials, perhaps as a forensic test. The unknown object may need to be painted or coated in some way so that its surface does not provide other hints.
A critical point to make here is that, whilst they may be able to state with a great deal of confidence that two materials have the same density or notthis does not mean that they are made from the same material.
Further chemical testing would be needed to make an absolute statement of that kind. This experiment was safety-checked in December A very small dimension of a regularly shaped object may be determined using density and its other dimensions.
For example, the thickness of a piece of aluminum foil could be determined from length, width, mass, and density.
Archimedes' Principle leads to the concept of specific gravity. CHEMISTRY I LAB: DENSITY WHAT TO TURN IN: Hypothesis, Data Table 1, Data Table 2, Calculations, Graph, Questions # OBJECTIVES To measure the mass and volume of samples of two different metals To calculate the density of unknown metals.
calculate the volume of your head? What about rock? The volume of an irregularly shaped object can be found by measuring the amount of water it displaces. One way to do this is to place the object in a known quantity of water and measure the volume of the two combined.
From this new volume, subtract the original volume of the water. Illustrative Example. Calculate the moment of inertia of a flat solid disk ofradius R and mass M aboutanaxis throughits center of mass andperpendicular to the plane of the disk.
Let us suppose the disk to be of thickness a, and made of a homogeneous material of density p. To calculate . Procedure for determining the density of a regular shaped object: 1) Select the regular shaped object 2) Using a triple beam balance, record the mass of the object to the nearest tenth of a gram.
(Be sure to do this with a dry object) 3) Using a metric ruler, measure the length, width, and height of the object.
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