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Transcript of Toothbrush Lab
The amount of water you collected is referred to as the volume of water. You should have noticed a change in the volume of water between Part 1 and Part 2. You will now calculate the average amount of water used in each part. Remember to set up the problem correctly, using units of measurement and showing all steps of the work.
To calculate an average, you must add together all of the values you collected and divide by the number of samples you obtained. An example of an average of sample data is shown below:
Objectives: After doing this lab, you should be able to
•explain how small individual changes in water use can have significant cumulative effects
•propose specific ideas for water conservation
•convert volume quantities over different time periods and include cost calculations
•plastic bucket or bowl
•timer, stopwatch or clock
1.Convert your units to gallons of water by choosing the appropriate conversion ratio. ◦1 gallon of water = 16 cups
◦1 gallon of water = 128 fluid ounces
◦1 gallon of water = 3,785 mL
2.Determine the number of samples you have. In this example, there are three samples.
3.Add the converted volumes together as follows:
Example: 0.1875 gallons + 0.21875 gallons + 0.203125 gallons = 0.609375 gallons
4.Divide the result by the number of samples. ◦ Example: 0.609375 ÷ 3 = 0.203125 gallons
◦This is the average of the three samples in the example. If desired, you can convert the information back to cups so it is easier to visualize. In this case, the average is 3 ¼ cups.
5.Now it is your turn. Calculate the average for Part 1 and Part 2.
6.Use the averages from Part 1 and Part 2 to determine the volume difference in water use between the two methods of tooth brushing. To calculate the volume difference, subtract the average in Part 2 from the average in Part 1.
On average, we could save 3,075.3121 mL of water by turning of the faucet when un-necessary.
2.If your town or city has a population of 70,000, how much water, in gallons, would be used daily if people allowed the water to run continuously while brushing their teeth? Assume people brush their teeth twice each day.
About 142,916 gallons of water per day. (not everyone has the same water flow, so the number varies)
3.How much water, in gallons, could be saved if all the townspeople conserved water while brushing by turning off the faucet? (Assume the same population size and that people brush their teeth twice each day.)
If using the conserving way of brushing teeth. The town would use about 29,167 gallons of water. Saving 113,749 gallons of water in a day.
4.In 2009, the state of Florida had a population of approximately 18,500,000 people. How much water, in gallons, could be saved if all Floridians were to conserve water while brushing? Assume the averages you collected in the lab reflect the state's average.
14,666,800 gallons of water saved (per day, brushing twice a day)
5.The values you calculated above represent one day's worth of water savings. Now calculate the yearly water savings, in gallons, for Florida, assuming 365 days in a year.
5,353,382,000 gallons saved in a year.
6.Assuming the average cost of water is approximately $0.04 per gallon, what would be the yearly economic savings in Florida if all Floridians were to conserve water while brushing?
Amount of Water
Amount of Water (when necessary)
Trial- Me: Saved 3,075.3125 mL of water
Trial- Person #1: Saved 3,193.5938 mL of water
Trial- Person #2: Saved 2,957.03 mL of water
16.5 cups/16 = 1.03125 gal X 3,785 = 3,903.28125 mL
3.5 cups/16 = 0.21875 gal X 3,785 = 827.96875 mL
Subtract: 3,903.28125 - 827.96875 = 3,075.3125 mL Saved
1.In thinking about the experimental design, why is it important to average the water use of at least three people?
To create a more accurate number of water saved. An average is more accurate because it helps broaden the numbers out. Only one trial is not a very scientific way to do an experiment.
2.Using your family as a model, show the calculations for the amount of money your family could save in one year by reducing its use of water during tooth brushing. Show your work. For this example, assume the cost of water to be $0.10 per gallon.
There are 7 people living at home right now. So, on average we could each save 228.125 gallons in a year. Multiplied by , that's 1,596.875 gallons a year. Saving us $159.69 in a year.
Households can save $60-$200 a year by fixing leaky faucets and conserve up to 1,660 gallons of water (one leaky faucet).