Skills And Processes Of Science, Quiz 1

1. Two students placed drops of water on an old penny and a new penny. They recorded how many drops could be placed on each. What is the dependent variable?

The number of students

The number of drops of water

The type of penny

The dependent variable in this experiment is the number of drops of water. The number of drops of water is being measured and recorded based on whether they can be placed on an old penny or a new penny. The dependent variable is the variable that is being affected or influenced by the independent variable, which in this case is the type of penny.

Explanation

The dependent variable in this experiment is the number of drops of water. The number of drops of water is being measured and recorded based on whether they can be placed on an old penny or a new penny. The dependent variable is the variable that is being affected or influenced by the independent variable, which in this case is the type of penny.

2. The following table provides data on the population growth of bacteria over time.

According to the data table, which of the following is true?

The graph of data would be a straight line with a slope of 2.

The number of bacteria doubles every twenty minutes.

At 140 minutes, there should be about 96 bacteria.

Based on the given data table, the number of bacteria consistently doubles every twenty minutes. This can be observed by comparing the population at each time interval. For example, at 20 minutes, the population is 48, and at 40 minutes, it is 96, indicating that it has doubled. This trend continues throughout the data, confirming that the number of bacteria doubles every twenty minutes.

Explanation

Based on the given data table, the number of bacteria consistently doubles every twenty minutes. This can be observed by comparing the population at each time interval. For example, at 20 minutes, the population is 48, and at 40 minutes, it is 96, indicating that it has doubled. This trend continues throughout the data, confirming that the number of bacteria doubles every twenty minutes.

3. Two students placed drops of water on an old penny and a new penny. They recorded how many drops could be placed on each. Before they write their results, they need to make a table. They decided to make a chart with two columns. What do the two columns represent?

Student 1 student 2

Old penny new penny

Drops of water drops of oil

The two columns in the chart represent the different types of pennies being tested - the old penny and the new penny. The students are recording the number of drops that can be placed on each type of penny.

Explanation

The two columns in the chart represent the different types of pennies being tested - the old penny and the new penny. The students are recording the number of drops that can be placed on each type of penny.

4. Students studied a species of fish. They wanted to find out if these fish grow faster in warmer water. The students designed an experiment to determine how different water temperatures affect the growth of the fish. They placed one fish in a tank at 26°C and another fish in a tank at 22°C. The fish were fed the same amount of food during the experiment. The mass of each fish was recorded at the beginning and at the end of the experiment. The data the students collected are shown in the table below.

The students concluded that warmer temperatures did increase growth in fish. However, they forgot to keep another factors constant. Looking at the students' data table, what is another possible conclusion they might have reached?

Small fish grow at a faster rate than large fish

Large fish grow faster than small fish

Guppies grow faster than angelfish

Angelfish grow faster than guppies

The possible conclusion that the students might have reached is that small fish grow at a faster rate than large fish. This conclusion can be drawn from the data table, as the fish in the tank at 26°C (warmer temperature) had a smaller starting mass but a larger ending mass compared to the fish in the tank at 22°C (cooler temperature).

Explanation

The possible conclusion that the students might have reached is that small fish grow at a faster rate than large fish. This conclusion can be drawn from the data table, as the fish in the tank at 26°C (warmer temperature) had a smaller starting mass but a larger ending mass compared to the fish in the tank at 22°C (cooler temperature).

5. Two students placed drops of water on an old penny and a new penny. They recorded how many drops could be placed on each. What data was being recorded as the results?

How many students were participating

The color of the penny

The number of drops of water

The age of the penny

The data being recorded as the results is the number of drops of water that could be placed on each penny.

Explanation

The data being recorded as the results is the number of drops of water that could be placed on each penny.

6. Two students placed drops of water on an old penny and a new penny. They recorded how many drops could be placed on each. What data was being recorded as the results?

How many students were participating

The color of the penny

The number of drops of water

The age of the penny

The data being recorded as the results is the number of drops of water that could be placed on each penny.

Explanation

The data being recorded as the results is the number of drops of water that could be placed on each penny.

7. To determine the mass of a snail, a student will place it on a glass dish and weigh the dish and snail. What should the student do first?

Weigh the dish before placing the snail on it and add this to the weight of dish and snail.

Weigh the dish before placing the snail on it and subtract this number from the weight of dish and snail.

Weigh a different dish and subtract its mass from the mass of the dish and snail.

Weigh a different snail and add its weight to the weight of the first snail.

The student should weigh the dish before placing the snail on it and subtract this number from the weight of dish and snail. This is because by weighing the dish before adding the snail, the student can determine the weight of just the snail by subtracting the weight of the empty dish from the combined weight of the dish and snail.

Explanation

The student should weigh the dish before placing the snail on it and subtract this number from the weight of dish and snail. This is because by weighing the dish before adding the snail, the student can determine the weight of just the snail by subtracting the weight of the empty dish from the combined weight of the dish and snail.

8. In an experiment, a set-up used to compare to the experimental set-up is called ________.

A control

A hypothesis

The independent variable

The dependent variable

A control is a set-up used in an experiment to provide a baseline for comparison. It is used to ensure that any changes or effects observed in the experimental set-up are due to the independent variable being tested, and not due to other factors. The control group is kept unchanged or given a standard treatment, allowing researchers to compare the results with the experimental group. This helps in determining the cause and effect relationship between the independent variable and the dependent variable.

Explanation

A control is a set-up used in an experiment to provide a baseline for comparison. It is used to ensure that any changes or effects observed in the experimental set-up are due to the independent variable being tested, and not due to other factors. The control group is kept unchanged or given a standard treatment, allowing researchers to compare the results with the experimental group. This helps in determining the cause and effect relationship between the independent variable and the dependent variable.

9. Dreissena polymorpha, the zebra mussel, is a species of mussel that is native to East European waterways. They are not native to the Great Lakes, but they have been introduced there. Researchers believe that zebra mussels are ten times more effective in removing toxic contaminants from polluted water than are native mussels. Which of these experiments would test this hypothesis?

The correct answer is to place 20 zebra mussels in a tank with PCBs and 20 native mussels in another tank with PCBs, and then test the PCB levels of each tank after one week. This experiment would test the hypothesis because it would allow for a direct comparison between the zebra mussels and the native mussels in the same conditions. By testing the PCB levels in each tank, researchers would be able to determine if the zebra mussels are indeed more effective in removing toxic contaminants compared to the native mussels.

Explanation

The correct answer is to place 20 zebra mussels in a tank with PCBs and 20 native mussels in another tank with PCBs, and then test the PCB levels of each tank after one week. This experiment would test the hypothesis because it would allow for a direct comparison between the zebra mussels and the native mussels in the same conditions. By testing the PCB levels in each tank, researchers would be able to determine if the zebra mussels are indeed more effective in removing toxic contaminants compared to the native mussels.

10. Students crossed male and female flies that had red eyes and recorded the eye color of their offspring. Their data are shown below. Using the data in the table, what is the approximate ratio of red-eyed offspring to brown-eyed offspring?

1:1

2:1

3:1

4:1

The data in the table shows that out of the total offspring, there are 3 red-eyed offspring for every 1 brown-eyed offspring. This means that the approximate ratio of red-eyed offspring to brown-eyed offspring is 3:1.

Explanation

The data in the table shows that out of the total offspring, there are 3 red-eyed offspring for every 1 brown-eyed offspring. This means that the approximate ratio of red-eyed offspring to brown-eyed offspring is 3:1.

11. The graphs below show the effects of temperature and pH on the reaction rate of an enzyme. Food will stay fresh longer when enzyme activity is slowed. Which of the following conditions would most likely slow enzyme activity?

Reducing pH from 8 to 7 by adding a weak acid

Increasing pH from 5 to 6 by adding a weak base

Reducing temperature from 30°C to 20°C by refrigeration

Increasing temperature from 30°C to 40°C by heating

Lowering the temperature from 30°C to 20°C by refrigeration would most likely slow enzyme activity. Enzymes are sensitive to temperature changes, and lowering the temperature decreases the kinetic energy of the enzyme molecules, reducing their ability to collide with substrates and catalyze reactions effectively. This decrease in enzyme activity would result in slower degradation of food, allowing it to stay fresh longer.

Explanation

Lowering the temperature from 30°C to 20°C by refrigeration would most likely slow enzyme activity. Enzymes are sensitive to temperature changes, and lowering the temperature decreases the kinetic energy of the enzyme molecules, reducing their ability to collide with substrates and catalyze reactions effectively. This decrease in enzyme activity would result in slower degradation of food, allowing it to stay fresh longer.

12. Students studied a species of fish. They wanted to find out if these fish grow faster in warmer water. The students designed an experiment to determine how different water temperatures affect the growth of the fish. They placed one fish in a tank at 26°C and another fish in a tank at 22°C. The fish were fed the same amount of food during the experiment. The mass of each fish was recorded at the beginning and at the end of the experiment. What was the independent variable?

The amount of food given to each fish

The percent change in mass of the fish

The starting mass of the fish

The temperature of the water

The independent variable in this experiment is the temperature of the water. The students wanted to determine how different water temperatures affect the growth of the fish, so they manipulated the temperature by placing one fish in a tank at 26°C and another fish in a tank at 22°C. They kept all other factors constant, including the amount of food given to each fish, the starting mass of the fish, and the percent change in mass of the fish. By changing the temperature of the water, the students were able to observe and measure the effect of temperature on the growth of the fish.

Explanation

The independent variable in this experiment is the temperature of the water. The students wanted to determine how different water temperatures affect the growth of the fish, so they manipulated the temperature by placing one fish in a tank at 26°C and another fish in a tank at 22°C. They kept all other factors constant, including the amount of food given to each fish, the starting mass of the fish, and the percent change in mass of the fish. By changing the temperature of the water, the students were able to observe and measure the effect of temperature on the growth of the fish.

13. Cheryl wants to perform an investigation that requires using hazardous chemicals. The following steps of the investigation are not in the correct order. 1. Perform the investigation. 2. Design the investigation. 3. Put on gloves, goggles, and an apron. 4. Dispose of waste materials. Which of these is the correct sequence of steps to safely complete the investigation?

1-3-4-2

3-2-1-4

4-1-3-2

2-3-1-4

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Explanation

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14. When you make a graph of data, the independent variable ______________________.

Goes on the x axis.

Goes on the y axis.

Can go on either axis.

When you make a graph of data, the independent variable goes on the x-axis. The x-axis represents the horizontal axis and is used to plot the independent variable, which is the variable that is being manipulated or controlled in the experiment. The dependent variable, on the other hand, goes on the y-axis, which represents the vertical axis. This is because the dependent variable is the variable that is being measured or observed and is expected to change in response to changes in the independent variable.

Explanation

When you make a graph of data, the independent variable goes on the x-axis. The x-axis represents the horizontal axis and is used to plot the independent variable, which is the variable that is being manipulated or controlled in the experiment. The dependent variable, on the other hand, goes on the y-axis, which represents the vertical axis. This is because the dependent variable is the variable that is being measured or observed and is expected to change in response to changes in the independent variable.

15. The chart below is the nutrition facts found on a bag of pretzels.

How would you determine the total number of calories in the entire bag?

Multiply 25 and 10

Multiply 25 and 120

Multiply 10 and 120

Multiply 120 and 23

To determine the total number of calories in the entire bag, you would multiply the serving size (10) by the number of calories per serving (120). This calculation gives you the total number of calories in the entire bag.

Explanation

To determine the total number of calories in the entire bag, you would multiply the serving size (10) by the number of calories per serving (120). This calculation gives you the total number of calories in the entire bag.

16. Two students placed drops of water on an old penny and a new penny. They recorded how many drops could be placed on each. What is the independent variable?

The number of students

The number of drops of water

The type of penny

The independent variable in this experiment is the type of penny. The students are testing how the type of penny (old or new) affects the number of drops of water that can be placed on it. They are not changing the number of students or the number of drops of water, so these variables are not independent variables in this experiment.

Explanation

The independent variable in this experiment is the type of penny. The students are testing how the type of penny (old or new) affects the number of drops of water that can be placed on it. They are not changing the number of students or the number of drops of water, so these variables are not independent variables in this experiment.