Unit 1: Science, Technology, & Engineering

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. In this experiment, which variable is the independent variable?

• distance traveled by the ball
• path of ball once it leaves the ramp
• height from which the ball is released
• time is takes the ball to hit the ground

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?

• The results explain why the materials perform differently.
• Clara can use a different heavier material to see if she obtains results that further support her hypothesis.
• Clara can change her experimental design or her hypothesis to identify possible future scientific investigations.
• The results can be communicated with others through newspapers, magazines, and the Internet to increase the validity of her results.

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 red whenever it is put into an acid solution.
• The substance will never turn green when it is put into an acid solution.
• The substance will not change colors when it is put into an acid solution.
• 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 exercises
• the pulse rates
• the volunteers
• the physician

Which of the following describes a qualitative observation?

• a measurement
• a numerical observation
• a non-numerical observation
• an observation that includes units

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.

• gigameter (Gm)
• megameter (Mm)
• kilometer (km)
• meter (m)

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

• a hand lens
• a microscope
• a metric ruler
• a graduated cylinder

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?

• coral reefs near the edges of a volcanic island
• hardened lava mixed with the coral reef of an atoll
• fossils of reef animals and plants found on volcanic islands
• volcanic rock under the lagoon and under a coral atoll that has formed

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?

• 6
• 3 cm
• 24 cm
• 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 Fahrenheit
• temperatures in degrees Celsius
• number of daylight hours
• number of days that have each temperature