A student records the color, smell, and texture of ten soil samples from a school garden and writes the observations in a data table. No variable is changed. What kind of investigation is this?

A class measures the mass of five different rock samples on a balance and puts the results side by side to see which is heaviest. Nothing is changed by the students. What kind of investigation is this?

A student waters identical bean plants with 2 g and 4 g of fertilizer, keeps every other condition the same, and includes a plant with no fertilizer. What kind of investigation is this?

A team tests how the length of a pendulum string affects the number of swings in 30 seconds. They try strings of 20 cm, 40 cm, and 60 cm. What is the independent variable?

A team tests how the length of a pendulum string affects the number of swings in 30 seconds. They try strings of 20 cm, 40 cm, and 60 cm. What is the dependent variable?

A student tests whether warmer water dissolves salt faster. She uses 100 mL of water in every cup, stirs each cup 20 times, and sets the water at 10 C, 30 C, and 50 C. Name one controlled variable.

A class tests whether a new plant food helps radish seedlings grow taller. Which setup is the control group?

A student wants to test whether a thicker sleeve keeps a drink hot longer. He uses a thicker sleeve AND a lid on one cup, and a thin sleeve with no lid on the other. Why is this not a fair test?

Three trials measured the temperature of a cooling cup of water after 10 minutes: Trial 1: 42 C, Trial 2: 44 C, Trial 3: 43 C. What is the mean of these three readings?

A class repeats a bouncing-ball measurement five times and takes the mean instead of using one measurement. Why do they do this?

A student times how long an ice cube takes to melt and gets 240 s, 250 s, 245 s, and 60 s. She notices the 60 s cube was placed on a sunny windowsill. What best explains the odd trial?

A student writes: 'The pond water smelled musty and looked cloudy green.' What type of data is this?

A student needs to measure the volume of an irregular pebble by water displacement. Which tool is correct for the measurement?

A student must measure the force needed to drag a wooden block across a bench. Which tool gives that measurement in newtons?

A student writes down: 'Do plants grow better with music?' A classmate says this is not investigable yet. What change makes it an investigable question?

A graph shows that as a town's ice-cream sales rose, pond water temperature also rose. A student claims ice-cream sales warm the pond. What conclusion do the data actually support?

A student plans to pour a warm liquid into a beaker on a hot plate. What safety procedure should come first?

A student notices a cracked thermometer on the lab bench during an investigation. What is the correct action?

Two websites report on a lake's water quality. One shows five years of measured oxygen readings from a university lab. The other is a boat company saying the lake is fine. Which source is more credible?

If one experiment supports a hypothesis, the hypothesis has been proven true.