Water Density Lab Report

I. Introduction
A. Purpose The purpose of this lab was to practice measuring the mass and volume of different samples and to calculate the density and specific gravity of those samples using the measurements.
B. Equipment
1. Electronic balance- The electronic balance is a device used to measure the exact mass of an object
2. Graduated cylinder- The graduated cylinder is a tool used to measure the volume of a liquid
3. Pipets- Pipets are small tubes that suck up and contain liquids
C. Technique
1. The water displacement technique is used to measure the volume of a solid object using a graduated cylinder and water. This works by filling up a graduated cylinder about halfway with water and then measuring the volume by looking at the lowest
point of the meniscus, or the curved top of the liquid. Then, slightly tilt the graduated cylinder sideways so that the solid object that is being measured for volume can slide down into the graduated cylinder without splashing water out. After this, the volume is measured again. In order to find the volume of the solid by itself, the volume of the water is subtracted from the volume of the solid in the water.
I.
Data tables
A. Qualitative table\
Sample number and name Color
Solid # 1 (Al Shot) Silver
Solid # 2 (Steel Shot) Brown/Copper water Clear
Vegetable oil Light Yellow
Mineral oil Clear Color/ Appearance of Samples

B. Quantitative
Liquid Data Table Water Vegetable Oil Mineral Oil
Mass of empty pipet (g) 0.87 0.80 0.88
Mass of pipet and liquid (g) 6.27 5.78 5.45
Mass of liquid (g) 5.40 4.98 4.57
Volume of liquid (mL) 5.32 5.21 5.31
Density of liquid (g/mL) 1.02 0.956 0.861
Specific gravity of liquid No specific gravity for water .937 .844

C. Quantitative
Solid Data Table Solid 1 Solid 2
Mass of solid (g) 18.35 49.57
Water volume at start (mL) 31.3 29.2
Water volume after solid is added (mL) 37.9 35.7
Volume of solid (mL) 6.6 6.5
Density of solid
(g/mL) 2.78 7.63
Specific gravity of solid 2.73 7.48
II. Computations
A. Volume of water displaced (Solid 1) Water volume with solid - Water volume at start = Volume of solid 37.9mL – 31.3 mL = 6.6 mL
B. Density = Mass/ Volume
1. H20 5.40g/5.32 mL= 1.02g/mL
2. Vegetable Oil 4.98g/5.21mL= 0.956g/mL
3. Solid 1 18.35g/6.6mL= 2.78g/mL C. Specific gravity = density of substance/ density of standard (water)
1. Vegetable
Oil 0.956g/mL = .937 1.02g/mL
2. Solid 1 2.78g/mL = 2.73 1.02g/mL IV. Error
A. Percent Error = I Experimental Value – Accepted Value I x 100 Accepted Value
1. Vegetable Oil
I 0.956g/mL - 0.952g/mL I x 100 = 0.4% Error 0.952g/mL

V. Conclusion This lab exemplified different methods of collecting data such as mass and volume and using formulas to calculate density, percent error and specific gravity from that data. Throughout this experiment we measured the mass and volume of two liquids and two solids. From this information we were able to calculate the density of these samples, the specific gravity and percent error. Percent error is the difference of a sample’s known value and the measured value divided by the known value and multiplied by one hundred. This formula gives you the percentage of human error in measurement which is always bound to happen because humans are not perfect. By simply measuring two types of data (mass and volume) we were able to calculate many other types of data such as density, percent error and specific gravity.
1.
Both of the liquid samples, vegetable oil and mineral oil, would float on water, whereas both solids one and two would not. The liquids would float on water because their densities are smaller than that of water and therefore water would sink to the bottom. Meanwhile, both of the solids have densities that are higher than water and therefore the solids would sink.
2. If you wanted to make layers of four liquids in a graduated cylinder you would have to put them in from highest density to lowest density because the higher the density the closer it will be to the bottom of your graduated cylinder.
3. Specific Gravity has no units, unlike density. In the calculation for specific gravity both of the units cancel each other out. Working with specific gravity would be different from working with density because there are no units to cancel out or to
convert.
4. In order to measure the density of a solid that floats on water you would first measure the mass of that object using an electronic balance. Then you would use the water displacement technique to measure the volume of the solid, but since the solid floats you would need to find something to push the solid down to submerge it in the water and then collect your data.

Advanced study questions answered on worksheet