Kadyn Kirby

Mathematics

1 September, 23:56

Selma hypothesizes that the mass of a sample of water will not change if it is frozen. She conducts an experiment to test her hypothesis. Her experimental steps are as follows:

1. Fill a beaker with 500 mL of water.

2.

3. Place the beaker in the freezer.

4. After the water freezes, place the beaker on the balance and measure its mass.

Which of the following steps is missing from Selma's experiment?

Place the beaker on the balance and measure its mass.

Run the water through a filter to make sure there are no impurities in it.

Set a timer for 2 hours.

Use a thermometer to measure the water's temperature.