Renee rolls a steel ball down a ramp. She conducts multiple trials by releasing the ball from varying heights on the ramp. For each trial, she measures and records the release height of the ball and the distance the ball travels away from the ramp before falling to the ground. The figure below shows the experiment. In this experiment, which variable is the independent variable?

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Clara tests a hypothesis that the heavier of two materials will insulate cold drinks better than the lighter-weight material. She adds equal volumes of the same cold beverage to two cups. One cup is made of lightweight plastic foam, and the other cup is made of a heavier, ceramic material. She records her results in a chart. How are these experimental results valuable to Clara?

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Clara can change her experimental design or her hypothesis to identify possible future scientific investigations.

Marissa is conducting an experiment in which she is testing a substance she believes will turn green when put into different acid solutions. She finds that sometimes the substance turns green, but at other times it turns red. What would be a logical hypothesis for her to develop for a new experiment with the substance?

The substance will turn green when it is put into an acid solution with a pH between 3 and 4.

The school physician performed an experiment to investigate the effects of aerobic exercise on high school freshmen. He examined 25 student volunteers, and then he had each student perform aerobic exercises, such as jogging, swimming, and bicycling. The doctor recorded the students’ pulse rates before each activity, during each activity, and after each activity. Which is the dependent variable in this experiment?

the pulse rates

One benefit of using SI units is the convenience of converting between the units using prefixes. The distance between two cities is 256,000 m. This is a large number that is not convenient to report or manipulate. Use the table below to determine which unit is the best way to report the distance between the cities.

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What scientific tool would best be used to study your cheek cells?

Coral atolls are coral reefs that surround an ocean lagoon. Charles Darwin believed atolls began as reefs around volcanic islands that eventually eroded, leaving the reefs behind. Which of these features would provide the best evidence for Darwin’s theory?

volcanic rock under the lagoon and under a coral atoll that has formed

The students in Mrs. Dhaibar’s science class take a test. The results of the test are shown in the table below. Mrs. Dhaibar creates a circle graph to display this data. Which grade does the shaded region correspond to?

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35%

A student conducted an investigation to see how high a rubber ball bounced when dropped. He conducted six trials and got the following results:
Trial 1: 22 cm
Trial 2: 25 cm
Trial 3: 25 cm
Trial 4: 23 cm
Trial 5: 22 cm
Trial 6: 25 cm
What is the mode for this data set?

25 cm

Jenna is collecting temperature data. She wants to find out how many days in May have a daytime high temperature of 15°C, 16 °C, and so on. She decides to use a line plot to organize her data. Which describes the values she should include on the x-axis of her line plot?

temperatures in degrees Celsius

The students in a science class created a scatter plot to show the results of a race. They chose to have the axes represent the ages of the participants and the time in which they finished the race. Their scatter plot is shown below. The students in the science class plan to conduct the experiment again. What prediction can you make about the next race after analyzing the data in the scatter plot?

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In general, the older a runner is, the longer it will take him or her to finish the race.

A scientist graphs the mass and volume of three samples, as shown in the graph below. Which personal trait does the scientist need when attempting to analyze data like the information shown here?

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logic

Which of the following best supports a scientific explanation?

experimental data obtained by making objective measurements

Household waste and trash is a problem that is addressed by many groups of people. Which group of people would most likely be responsible for answering the question “How can we build a system to more efficiently recycle glass?”

engineers