Lab Report Sample (Page 2 of 2) in pdf

Name___________________________________________Period______Entry #_______

Data/Results:

Figure 1:

Number of Drops in Each Trial

Trial #

Plain Water

Soapy Water

Figure 1 shows the recorded numerical data for the number of drops in each trial of plain

water and soapy water.

Figure 2:

Number of Drops in Each Trial

Number of

Drops

Plain

Soapy

Trial Number

Figure 2 is a bar graph of the number of drops of plain water and soapy water. Each type

of water is shown plotted next to each other in 5 different trials.

Summary and Conclusion:

The purpose of this lab is to explore how soap added to water will affect cohesion of

water molecules. Drops of water were placed on a penny and counted, and this was

repeated with soapy water. The initial observation, as shown in the graph above, was

that the number of drops decreased when soap was added to the water, and therefore the

hypothesis was accepted. Soap has the ability to slide in between water molecules,

thereby decreasing cohesion because they lose the ability to stick to each other. This was

The hypothesis was observed and supported in the laboratory, and is now accepted as

truth based on the results. The experiment was performed in a non-controlled

environment, so there was some variance between drops. An improvement would have

been to use a drop counter, which is a device that controls the amount of liquid in each

drop and the time allotted between drops. To carry on with this experiment, another type

of soap could be tested, such as bar soap or laundry detergent, or even trying another

variable, such as changing the temperature of the soap and determining whether warm

soap or cold soap would make a difference in the drops allowed on the penny. A new

concept learned is that of the effect of a surfactant which is to reduce cohesion in

aqueous solutions. (A lab extension may be substituted for a new concept learned)

Lab Report Sample Page 2