During this lab activity, my partner and I will test the effectiveness of different hand-washing times, techniques, and materials. The objective of this activity is to answer the question: How long does it take to effectively wash your hands? I hypothesize that it takes around 35 seconds to effectively wash your hands, because it takes a while to rub off all the germs on your hands. I think the longer you wash your hands for, the cleaner they will get. Safety Notes: -be sure you are using washable paint that can be removed with soap and water. Wash your hands carefully after completing the lab activity -be sure that you eave permission and supervision from a guardian before completing this lab activity -do not touch your face with paint and avoid getting paint in your eyes protect the work surface, using newspaper or other covering, and wear an apron or old clothes Materials: -timer or watch that counts seconds -sink -blindfold -washable paint or food coloring -paper towels -soap -partner (this can be a friend or family member) -newspaper to protect the work surface (optional) Proceed re: 1.
Pick one person to be the hand washer and one person to be the timekeeper. You will both have the opportunity to complete each of the experiments, so you ill each be washing your hands two times. 2. Washer #1 should put a small amount (about a tablespoon) of washable paint on the palm of one hand and spread it evenly over both hands. Be sure to cover the backs of the hands and the skin next to and under the fingernails. Allow the paint to dry completely. 3. Go to the skink and blindfold Washer #1 so he or she can’t see his/her hands. Turn on warm water.
Have washer #1 wash with just water for one second. After one second, have the timekeeper blot dry the washer’s hands by very lightly touching the paper towel to the skin. Use the scoring guide to record the lankiness on the “water only’ data table in the row marked ‘Washer #1. ” Do not let Washer #1 see his/her hands, and be sure that you do not give away any hints about how clean they are. 4. Have the washer wash for four more seconds with just water. Again, lightly blot the washer’s hands and record their cleanliness in the data table. Have the washer wash for 15 seconds more with water. Once again, blot and record the cleanliness on the data table. 6. Take the blindfold off and allow the washer to completely clean his/her hands. 7. Change roles and repeat steps 2 through 6 with washer #2. Record these results on the second row of the data table under Washer #2. 8. Now change roles again so that washer #1 is back to the role of hand washer. Repeat steps 2-6, having the washer use soap each time. Record the results in the appropriate row of the data table. 9.
It is now time for Washer #2 to repeat steps 2-6 using soap each time. Record these results in the second row of the data table. Scoring Guide: Completely Dirty Very Dirty Somewhat Dirty Slightly Dirty Clean 4 3 2 Data and Observations: Water Only: Total Wash Time (in seconds) O Seconds 1 Second 5 Seconds 20 Seconds Washer #1 Washer #2 Average Cleanliness Score 3. 5 Soap and Water: 1. 5 Data Analysis: Just water: With Soap and Water: Conclusion: 1. How do the results of the four trials compare? In all four trials, they all started out at O seconds with a cleanliness score of 4.
As time went on, the hands got cleaner and cleaner. The hands were much cleaner when people used soap. When you use just water, your hands leave a lot of paint on them, and are much dirtier than when you used soap. 2. What, if any, errors or inconsistencies may have occurred in this experiment? Some inconsistencies may have been a slightly different amount of paint during each experiment and the speed of washing your hands would be different each time you wash them. The amount of soap could have been a little different each time, along with the water pressure. 3.
What suggestions do you have for improving this lab and minimizing errors or inconsistencies? Be specific. To improve this lab and minimize errors or inconsistencies could be to set an amount of soap to use during each washing. Also, you should set an amount of water pressure (such as turning the sink knob all the way), because the more water, the cleaner the hands will be. Also, set an exact amount of paint you need each time. 4. Based on these results, what is the importance of soap and time for effective hand washing? Based on these results, soap and time are needed for effective hand washing.
When soap was used, it got off much more of the paint than when only water was used. The paint is like germs, so more germs will wash off your hands when you use soap. The hands were significantly cleaner the longer they were washed for. When washed for the longest time period, there was a significant difference in the amount of paint left to be washed off. When you wash your hands longer, you are allowing many more germs to be washed off your hands. Using a combination of soap and time, you will be able to get your hands very clean. 5.
What areas of the hands retained the paint the longest, requiring careful scrubbing to get clean? Around the fingernails took a very long time to get clean and required careful scrubbing Also, the skin around the joints in the finger were hard to get clean. 6. Analyze the graphs. What do they indicate about the time it may take to effectively wash your hands? The graphs show that it will take 20 or more seconds to effectively wash your hands. When the line graph reaches the x-axis that is when the hands are completely clean, because that would mean he cleanliness score is O.