**Lab – Introduction to Science**

**Exercise 1: Data Interpretation**

Dissolved oxygen is oxygen that is trapped in a fluid, such as water. Since many living organism requires oxygen to survive, it is a necessary component of water systems such as streams, lakes and rivers in order to support aquatic life. The dissolved oxygen is measured in units of ppm—or parts per million. Examine the data in Table 4 showing the amount of dissolved oxygen present and the number of fish observed in the body of water from which the sample was taken; finally, 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 |

1. What patterns do you observe based on the information in Table 4?

2. 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.

3. What would your experimental approach be to test this hypothesis?

4. What would be the independent and dependent variables?

5. What would be your control?

6. What type of graph would be appropriate for this data set? Why?

7. Graph the data from Table 4: Water Quality vs. Fish Population table (found at the beginning of this experiment).

8. Interpret the data from the graph made in Question 7.

**Exercise 2: Testable Observations**

Determine which of the following observations are testable. For those that are testable:

· Determine if the observation is qualitative or quantitative

· Write a hypothesis and 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 (charts, graphs, types)?

· How will you analyze your data?

1. A plant grows three inches faster per day when placed on a window sill than it does when placed on a on a coffee table in the middle of the living room.

2. The teller at the bank with brown hair and brown eyes is taller than the other tellers.

3. When Sally eats healthy foods and exercises regularly, her blood pressure is 10 points lower than when she does not exercise and eats fatty foods.

4. The Italian restaurant across the street closes at 9 pm but the one two blocks away closes at 10 pm.

5. For the past two days, the clouds have come out at 3 pm and it has started raining at 3:15 pm.

6. George did not sleep at all the night following the start of daylight savings.

**Exercise 3: Conversion**

For each of the following, convert each value into the

designated units.

1. 46,756,790 mg = _______ kg

2. 5.6 hours = ________ seconds

3. 13.5 cm = ________ inches

4. 47 °C = _______ °F

**Exercise 4: Accuracy and Precision**

For the following, determine whether the information is accurate, precise, both or neither.

1. During gym class, four students decided to see if they could beat the norm of 45 sit-ups in a minute. The first student did 64 sit-ups, the second did 69, the third did 65, and the fourth did 67.

2. The average score for the 5th grade math test is 89.5. The top 4th graders took the test and scored 89, 93, 91 and 87.

3. Yesterday 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 for September is only 75 °F degrees!

4. Four friends decided to go out and play horseshoes. They took a picture of their results shown to the right:

5. A local grocery store was holding a contest to see who could most closely guess the number of pennies that they had 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.

**Exercise 5: Significant Digits and Scientific Notation**

**Part 1:** Determine the number of significant digits in each number and write out the specific significant digits.

1. 405000

2. 0.0098

3. 39.999999

4. 13.00

5. 80,000,089

6. 55,430.00

7. 0.000033

8. 620.03080

**Part 2:** Write the numbers below in scientific notation, incorporating what you know about significant digits.

1. 70,000,000,000

2. 0.000000048

3. 67,890,000

4. 70,500

5. 450,900,800

6. 0.009045

7. 0.023

**Exercise 6: Percentage Error**

In the questions below, determine the percentage error. Show your work on all problems.

1. 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 he is holding 81 cents. The dad opens his hand and displays 90 cents. Did the son guess close enough to receive the money from his father?

2. A science teacher tells her class that their final project requires the 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?

3. A locomotive 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 it actually took them 3.26 hours. The train company prides itself on always having its trains to the station within a 3% error of the expected time. Will the train company live up to its reputation on this trip?

4. A coach tells his little league players that hitting a .275 batting average, within 7% percentage error, means that they had a really great season. Seven year old Tommy ended the season hitting a .258 batting average. According to his coach, did he have a great season?

**Exercise 7: Experimental Variables**

Determine the variables tested in the each of the following experiments. If applicable, determine and identify any positive or negative controls.

Observations

1. 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 is surveyed.

A. Independent Variable:

B. Dependent Variable:

C. Controlled Variables/Constants:

D. Experimental Controls/Control Groups:

2. 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*

All of the Petri dishes received the same volume of agar, and were the same shape and size. During the experiment, the temperature at which the Petri dishes were stored, and at the air quality remained the same. After one week the amount of bacterial growth was measured.

A. Independent Variable:

B. Dependent Variable:

C. Controlled Variables/Constants:

D. Experimental Controls/Control Groups:

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