Tom wants to find out whether the amount of sunlight changes how tall bean plants grow. He sets up four bean plants. To make it a fair test, which one thing should be different for each plant?
Sana put identical ice cubes on same-sized plates made of different materials, in the same warm room, and timed how long each took to melt. The more easily heat passes through a plate, the faster the ice cube on it melts. She then tested a stone plate, and its ice cube melted in 16 minutes. Which list orders all five materials from the one heat passes through most easily to the one it passes through least easily?
Ella hung a weight on a string and let it swing. She counted how many full swings (there and back) it made in one minute, using strings of different lengths. Her results are in the table. If the same pattern continues, about how long would the string need to be for 15 full swings in one minute?