Question:How Will Increasing Amounts of Laundry Detergent Affect the Temperature of Water?

How Laundry Detergent Affects Water Temperature

Answer Key

Question:How will increasing amounts of laundry detergent affect the temperature of water?

Hypothesis:

Varies______

Materials

Graduated cylinderWater (100mL for each beaker)

5 beakers (250 mL)Stirring rod or coffee stirrers

Thermometers or temperature probes and LabQuest

Dry Laundry detergent (use the same brand for each group)

Triple Beam Balance ScalePan or container to hold detergent

Procedures

Set up 5 beakers and label them A – E.
Using a graduated cylinder, pour 100 mL of water (room temperature)into each beaker.
Using a thermometer or temperature probe, measure the temperature of the water in Celsius for each beaker, A – E, and record in the table.
Using the Triple Beam Balance Scale, measure out 5g of laundry detergent using a pan or container. Be sure to include the mass of the container.
Add the 5g of laundry detergent to cup A, stir for one minute and take the temperature using a thermometer or temperature probe. Record in table.
Repeat steps 4 & 5 using 10g of laundry detergent for cup B, 15g of laundry detergent for cup C,

20g of laundry detergent for cup D, and 25g of laundry detergent for cup E.

Observations

Describe what you observed. Be sure to include discussion of chemical change/s.

___Answers will vary but should indicate a slight increase in temperature with an increase in the amount of detergent added.______

Which chemical is producing the temperature change—the solid or the water? How do you know?

Dissolving powders and temperature changes.When the detergent is added to the water, the powders break apart and spread out in the water (i.e., they dissolve in the water). This causes the solution temperature to change.When it dissolves, each powder molecule detaches from other powder molecules and becomes surrounded by water molecules. This change in arrangement either absorbs or releases energy. The exchange of energy causes the temperature of the solution to change. When the powder molecules release energy in the solution, it heats up. You can use the temperature of the water to see the change of energy transferred.______

Which chemical changes more when they are combined?

__If the water were to evaporate and all that was left was the laundry detergent, the laundry detergent would fail to maintain its properties because some of the chemical components in the detergent would attach to the water molecules making the water contaiminated.Specialnote- Teachers can refer to this article, “A Study on Chemical Contamination of Water Due to Household Laundry Detergents” by GeetuGoel and Surinderjit Kaur in the Journal of Human Ecology (2012), Volume 38, Number 1, pages 65-69._

DATA TABLE

Beaker / Amount of
detergent
added / Group Water
Temperature (°C) / Group Water
Temperature (°C) / Class Average
Water and
Laundry Detergent
Temperature (°C) / Class Average
Water and
Laundry Detergent
Temperature (°C)
A / 5g / 24.3°C* / 24.5°C* / varies / varies
B / 10g / 24.2°C* / 25.0°C* / Varies / Varies
C / 15g / 23.8°C* / 25.3°C / Varies / Varies
D / 20g / 23.8°C* / 25.9°C / Varies / Varies
E / 25g / 23.8°C* / 26.8°C / varies / varies

(*These can vary as well, what is shown is one sample)

Checklist for Graphs

□Export the chart above into Excel

□Create a scatter plot graph.

□Right click one of the points on the graph, and choose “AddTrendline”.

□Make sure you click “Display Equation on Chart”, and “Display R squared value on Chart”.

□ Choose Linear to check if the graph has linear or nonlinear associations.

□Export the data into GeoGebra and check for outliers and clusters.

Excel Sample:
Beaker / Amt of Det / Water / Water & Det / Water T / Water & Det T
A / 5g / 24.3°C* / 24.5°C* / 24.3 / 24.5
B / 10g / 24.2°C* / 25.0°C* / 24.2 / 25
C / 15g / 23.8°C* / 25.3°C / 23.8 / 25.3
D / 20g / 23.8°C* / 25.9°C / 23.8 / 25.9
E / 25g / 23.8°C* / 26.8°C / 23.8 / 26.8
Amt of Det / Difference of T
5 / 0.2
10 / 0.8
15 / 1.5
20 / 2.1
25 / 3

Example of Scatter Plot showing Trendline with y intercept, R squared value, linear trend of values

Example using Water Temperature A3, A7 and Detergent with water

Temperature B3, B7

Conclusion

Answers can vary but should include support/failed to support the hypothesis and use a discussion of the data. Example - Although the data support my hypothesis that the detergent would increase the temperature, no chemical reaction is occurring. The powders don’t change into something new, and neither does the water. Instead the molecules are just arranged in a different way, and, in moving to their new arrangement, they either release or absorb energy.