Robert is performing an experiment, testing to see if dissolving salt in water makes the water corrode steel rods more quickly. In this experiment, what are some values that Robert will want to hold constant. (check all that apply)

Question

the amount of salt dissolved in the water

the temperature of the saltwater

the amount of corrosion on each steel rod

the type of steel the rods are made from

the amount of time the rods spend in the saltwater

Answer 1

In Robert's experiment, it is crucial to hold certain variables constant to ensure that any changes observed in the rate of corrosion are due to the amount of salt dissolved in the water. Here are the values he will want to hold constant:

1. The amount of salt dissolved in the water - This is the independent variable that he is testing, so it should be controlled.

2. The temperature of the saltwater - Temperature can affect the rate of corrosion, so it should be kept constant.

3. The type of steel the rods are made from - Different types of steel may have different corrosion resistance, so holding this constant is essential.

4. The amount of time the rods spend in the saltwater - This allows for a fair comparison between the different conditions tested.

The amount of corrosion on each steel rod is not a value to hold constant. Instead, it is the dependent variable that Robert will measure to observe the effect of salt on the corrosion rate.

So, the values that Robert will want to hold constant are:

• The amount of salt dissolved in the water
• The temperature of the saltwater
• The type of steel the rods are made from
• The amount of time the rods spend in the saltwater