Viscosity Lab
Sally Student Period 9
November 8, 2006 Lab Report
I – The Problem
Does the temperature of a liquid affect its viscosity?
II – Background Information
The lab was designed to study the effects of changing a liquid’s temperature and its overall viscosity. A liquid’s viscosity is its ability to resist flow. In this lab, a liquid’s viscosity was determined by how fast a nut traveled through the corn syrup; the faster the speed, the less viscous the liquid. Liquid corn syrup will be manipulated to three separate temperatures, a hot trial, room temperature trial, and a cold trial. The speed with which a nut will travel through the corn syrup in those three trials will be measured and recorded.
III – Hypothesis
If the temperature of liquid affects its viscosity, then increasing the liquid’s temperature will decrease its viscosity.
IV – Apparatus
1 - 1000 mL Beaker
2 – 100mL graduated cylinders
1 – Ringstand
1 – Bunsen burner
1 - cooler
3 – metal nuts
1- stop watch
V – Materials
200mL of corn syrup
800mL of water
150cm of string
matches
ice
10cm of masking tape
VI – Procedures
1. Take the two graduated cylinders and with the tape, mark the distance from the 70mL line to the 10mL line. This will be the start and stop points. Measure and record this distance.
2. Pour 100mL of corn syrup in both graduated cylinders.
3. Take one graduated cylinder and place it in the ice cooler.
4. With the second graduated cylinder, complete the first temperature trial. Record the liquid’s temperature with a Celsius thermometer. With approximately 50cm of string tied to the nut, drop the metal nut into the corn syrup. When it passes the first taped marker, start timing with the stopwatch. When it passes the second taped marker, stop timing. Record your data.
5. Repeat timing for four more trials.
6. When complete with the room temperature trials, place the graduated cylinder in approximately 800ml of water and place on the ring stand to heat.
7. While the hot temperature trial is heating, proceed with the cold temperature trial. Record the liquid’s temperature. Drop the metal nut and record the time it takes to travel through the corn syrup. Complete five separate trials.
8. Complete the final trial by removing the beaker form the heat and recording the temperature of the corn syrup. Drop the metal nut and record the time it takes to travel through the corn syrup. Complete five separate trials.
VII – Observations
The data shows a relevant effect between the temperature of a liquid and its overall viscosity. Data collected shows that as the temperature increased the time it took the nut to travel a set distance decreased. Similarly, as the temperature decreased, the time it took the nut to flow through the liquid significantly increased. Five trials were completed at each temperature and all of the trials resulted in similar times. A particularly significant result was seen in which the speed of the nut nearly doubled when in room temperature corn syrup to hot corn syrup.
Does Temperature Effect Viscosity?
Trial / Hot Bath(sec.) / Room Temperature (sec.) / Ice Bath
(sec.)
1 / 3.9 / 8.9 / 19.8
2 / 2.7 / 7.7 / 22.1
3 / 3.5 / 6.7 / 24
4 / 3.7 / 6.8 / 26
5 / 3.5 / 6.6 / 21.7
Does Temperature Effect Viscosity?
Speed = distance/time
Temperature / Distance traveled(cm) / Average time
(sec) / Average Speed (cm/sec)
Cold (9˚C) / 7.0 / 3.36 / .48
Room Temp. (21˚C) / 7.0 / 6.7 / 1.50
Hot (32˚C) / 7.0 / 23.5 / 3.09
VIII – Conclusion
Answer:
A lab was performed in order to study the concept of viscosity. Specifically, the effects of temperature on a liquid’s viscosity were researched. The hypothesis previously stated was, “If the temperature of liquid affects its viscosity, then increasing the liquid’s temperature will make it less viscous.” Viscosity is the property of a liquid to resist its ability to flow. By increasing or decreasing a liquid’s temperature it was predicted that the liquid’s viscosity would be affected. It was found that temperature did affect a liquid’s ability to flow. As temperature increased, its viscosity decreased. The liquid was placed in three different temperature trials and the speed with which a metal nut traveled through it was measured. The faster that a nut traveled would correlate to how thin the liquid got which, in turn, would mean that the liquid was less viscous.
Interpret:
Based on data collected, the hypothesis was supported. The speed at which the nut traveled through the corn syrup cooled to 9˚C was .48 cm/sec while the nut traveled at a speed of 1.50 cm/sec at 21˚C and finally at a significantly higher speed of 3.09 cm/sec at 32˚C (see graph). As the temperature of the liquid was raised, the nut traveled more quickly through the corn syrup. The liquid was becoming thinner as molecules spread out. The thinning of the liquid allowed the nut to drop at such an increased rate. In contrast, as the liquid was cooled, it became thicker as its molecules slowed. The metal nut measured average times of 22.7 sec. to travel the distance of 10.8cm (see graph).
Prediction:
Trials performed by other students in class further supported these findings. Some students found difficulty in accurately measuring the times of the metal nut drop, but overall the class data was similar. Further study could be done as to how temperature affects other types of liquids such as motor oil or shampoo. It is predicted that similar results would be found and that temperature would also affect the viscosity of those liquids.
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