2. does the amount of iron in the water affect plant growth?

hypothesis:

use if and then

Yes, the amount of Iron can affect the growth of plant.

Explanation:

Iron is essential micro-nutrient for the growth of plant but it is required only in small amount. Iron is required when plant produces chlorophyll and this gives plants oxygen and healthy green color but if a plant is suffering from iron deficiency then the plant's growth becomes stunted and leaves color changes to yellow. For plants requirement of iron is just 1 to 1.5 lb per acre whereas, requirement of nitrogen is 75 to 200 lb per acre.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it