ACT Practice Questions — All Questions

A student heats water and records its temperature. Time (min): 0, 5, 10, 15. Temperature (°C): 20, 30, 40, 50. If the trend continues, what is the predicted temperature at 20 minutes?

• a.70
• b.50
• c.55
• d.60✓

The temperature rises 10 °C every 5 minutes (a constant rate). Continuing the pattern from 50 °C at 15 minutes adds another 10 °C, giving 60 °C at 20 minutes.

A plant is given fertilizer and its height is measured. Fertilizer (g): 0, 2, 4, 6. Height (cm): 5, 9, 13, 17. If the trend continues, what height is expected at 8 g of fertilizer?

• a.19
• b.21✓
• c.20
• d.23

Height increases by 4 cm for every 2 g of fertilizer added (a constant rate). Continuing from 17 cm at 6 g adds another 4 cm, giving 21 cm at 8 g.

A student drops a ball from different heights and measures how high it bounces. In this experiment, which is the independent variable (the one deliberately changed)?

• a.bounce height
• b.air temperature
• c.ball mass
• d.drop height✓

The independent variable is the one the experimenter deliberately sets and varies. Here the student chooses the drop height, and the bounce height is the measured (dependent) result.