Lab 1

Exercise 1: Data Interpretation Dissolved oxygen is oxygen that is trapped in a fluid. Since many living organisms require oxygen to survive, it is a necessary component of water systems (streams, lakes, rivers, etc.). Dissolved oxygen is measured in units of parts per million (ppm). Examine the data in Table 4, which shows the amount of dissolved oxygen present in a body of water and the number of fish observed in the sample. Then, answer the questions below. Table 4: Water Quality vs. Fish Population Dissolved Oxygen (ppm) 0 2 4 6 8 10 12 14 16 18 Number of Fish Observed 0 1 3 10 12 13 15 10 12 13 What patterns do you observe based on the information in Table 4? As the parts per million dissolved oxygen increases, the number of fish increases to 15, and then decreases even as the dissolved oxygen continues to increase. Develop a hypothesis relating to the amount of dissolved oxygen measured in the water sample and the number of fish observed in the body of water. When the dissolved oxygen is at 12ppm, the number of fish observed will be at its greatest, and as the ppm increases past 12ppm, the number of fish will slightly decrease. What would your experimental approach be to test this hypothesis? Identify varying bodies of water with different levels of dissolved oxygen and determine whether the rate of fish decreases when the level passes 12ppm, and if the number of fish increases as the oxygen level increases until it reaches 12ppm. What would be the independent and dependent variables? The independent variable would be the dissolved oxygen level and the dependent variables would be the number of fish. What would be your control? The type of body of water used such as a stream, lake, river, or an ocean. Exercise 2: Testable Observations Determine which of the observations below are testable. For those that are testable: Determine if the observation is qualitative or quantitative. Write a hypothesis and a null hypothesis. What would be your experimental approach? What are the dependent and independent variables? What are your controls - both positive and negative? How will you collect your data? How will you present your data (e.g., charts, graphs, types)? How will you analyze your data? Observations A plant grows 3 cm faster per day when placed on a window sill than it does when placed on a coffee table in the middle of the living room. The observation is quantitative. The plant grows faster on the window sill because it has more sunlight, which is what causes plants to grow. The plant does not grow faster because it is on the window sill. The experiment would be to have two plants, one placed in the window sill and one on the coffee table. Over the course of two weeks, measuring the growth each day, we could determine whether the statement is true. The independent variable is the area in which the plant is placed and the dependent variable is how fast it grows in each place. The controls in the experiment is the amount of sunlight the two plants receive. The positive control is in the plant that sits on the windowsill and receives sunlight, and the negative control is the plant that sits on the coffee table and does not receive sunlight, thus concluding that it will not grow as fast. I will collect my data using a ruler to measure the growth each day and a table to record the data found. In will present the data, once collected, using a line graph to indicate which plant grew faster. I will analyze the data by looking at the graph and noting if the plant in the windowsill grew 3 cm faster, which will be easily identifiable due to the clearness of the graphed information. The bank teller with brown hair and brown eyes is taller than the other tellers. Not Testable. When Sally eats healthy foods and exercises regularly, her blood pressure is 10 points lower than when she eats fatty foods and does not exercise. The observation presented is quantitative. Sally’s blood pressure is affected by what foods she eats and the amount of exercise she has each day. Sally’s blood pressure is not affected by foods or exercise. The experiment that could be conducted to verify this observation would include monitoring Sally’s blood pressure for a month, and every other week would alternate Sally eating healthy and working out and eating fatty foods with no exercise. The independent variable is what Sally eats and whether or not she exercises, and the dependent variable is sally’s blood pressure. The controls would be the kind of food she eats, the positive being the healthy foods and the negative being the fatty foods. I would collect the data at the end of each day using a blood pressure monitor and chart it on a table. At the end of the month, I would chart the changes in a line graph with days on one side and blood pressure on the other. I will be able to analyze this data by noting if Sally’s blood pressure does in fact increase 10 points on the days she does not exercise or eat healthy. The Italian restaurant across the street closes at 9 pm, but the restaurant two blocks away closes at 10 pm. Not Testable. For the past two days, the clouds have come out at 3 pm, and it has started raining at 3:15 pm. Not Testable George did not sleep at all the night following the start of Daylight Savings Time. Not testable. Exercise 3: Conversion Use Figure 9 to convert each value into the designated units. Figure 9: Conversions for temperature, time, mass, and length. 46,756,790 mg = 46.75679 kg 5.6 hours = 20,160 seconds 13.5 cm = 5.3 inches 47 °F = 8.3 °C Exercise 4: Accuracy and Precision Determine whether the following statements are accurate, precise, both, or neither. Circle your answer. 203200081089500 During gym class, four students decided to see if they could perform the norm of 45 sit-ups in one minute. The first student did 64 sit-ups, the second did 69, the third did 65, and the fourth did 67. Accurate Precise Both Neither 127000062357000The average score for the 5th-grade math test is 89.5. The top 5th graders took the test and scored 89, 93, 91, and 87. Accurate Precise Both Neither 303530061722000Yesterday the temperature was 89 °F, tomorrow it’s supposed to be 88 °F, and the next day it’s supposed to be 90 °F, even though the average temperature for September is 75 °F. Accurate Precise Both Neither Four friends decided to play horseshoes. They took a picture of their results: 393700180467000 Accurate Precise Both Neither 306070081280000A local grocery store held a contest to see who could most closely guess the number of pennies inside a large jar. The first six people guessed the numbers 735, 209, 390, 300, 1005, and 689. The grocery clerk said the jar actually contains 568 pennies. Accurate Precise Both Neither Exercise 5: Significant Digits And Scientific Notation Part 1 Determine the number of significant digits in each number, and write the specific significant digits. 405000 The Three significant figures are 405 0.0098 The two significant figures are 98 39.999999 The eight significant figures are 39999999 13.00 The four significant figures are 1300 80,000,089 The eight significant figures are 80000089 55,430.00 The seven significant figures are 5543000 0.000033 The two significant figures are 33 620.03080 The eight significant figures are 62003080 Part 2 Convert each number into scientific notation. 70,000,000,000 7 x 1010 0.000000048 4.8 x 10-8 67,890,000 6.789 x 107 70,500 7.05 x 104 450,900,800 4.509008 x 108 0.009045 9.045 x 10-3 0.023 2.3 x 10-2 Exercise 6: Percentage Error Determine the percentage error in each scenario. Show your work on all problems. A dad holds five coins in his hand. He tells his son that if he can guess the amount of money he is holding within 5% error, he can have the money. The son guesses that dad is holding 81 cents. The dad opens his hand and displays 90 cents. Did the son guess close enough to get the money? No, the son did not guess close enough to get the money from his father. His percent error is 10. |90-81|/90 x 100 = 10 A science teacher tells her class that their final project requires students to measure a specific variable and determine the velocity of a car with no more than 2.5% error. Jennifer and Johnny work hard and decide the velocity of the car is 34.87 m/s. The teacher informs them that the actual velocity is 34.15 m/s. Will Jennifer and Johnny pass their final project? Jennifer and johnny will pass their final project because their percent error was 2.1%. |34.15-34.87|/34.15 x 100 = 2.1 A train is on its way from Chicago, IL to Madison, WI. The trip is said to last 3.15 hours. When the train arrives in Madison, the conductor notices the trip took 3.26 hours. The train company prides itself on always having its trains arrive within a 3% error of the expected time. Will the train company live up to its reputation on this trip? No, the train company will not live up to its reputation on the trip because the percent error was 3.5% |3.26-3.15|/3.26 x 100 =3.5 A coach tells his Little League players that hitting a 0.275 batting average, within 7% error, means that they had a really great season. Seven-year-old Tommy ended the season with a 0.258 batting average. According to his coach, did Tommy have a great season? Yes, Tommy did have a great season because his percent error was 6.7% |0.275-0.258|/0.258 x 100 =6.7 Exercise 7: Experimental Variables Determine the variables tested in each of the following experiments. If applicable, determine and identify any positive or negative controls. A study is being done to test the effects of habitat space on the size of fish populations. Different sized aquariums are set up with six goldfish in each one. Over a period of six months, the fish are fed the same type and amount of food. The aquariums are equally maintained and cleaned throughout the experiment. The temperature of the water is kept constant. At the end of the experiment, the number of surviving fish are surveyed. A. Independent Variable: The size of the aquarium B. Dependent Variable: The number of surviving fish C. Controls: The temperature and food, and cleaning of each aquarium To determine if the type of agar affects bacterial growth, a scientist cultures E. coli on four different types of agar. Five petri dishes are set up to collect results: • One with nutrient agar and E. coli • One with mannitol-salt agar and E. coli • One with MacConkey agar and E. coli • One with LB agar and E. coli • One with nutrient agar but NO E. coli A. Independent Variable: The type of agar B. Dependent Variable: Bacterial Growth C. Controls: The petri dish with nutrient agar but no E. Coli