Investigating the effects of different lead chloride concentrations on the growth of cress seedlings

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A-Level Biology Coursework:

Investigating the effects of different lead chloride concentrations on the growth of cress seedlings

Ying-Jun Ng

Candidate number: 2135

Aim

To investigate the effect of different lead chloride concentrations on the growth of cress seedlings

Background Information

Lead (Pb) is the heaviest non-radioactive metal with an atomic number of 82 and atomic weight of 207. Lead is a soft, malleable but dense, ductile heavy metal with poor electrical conductivity. It is highly resistant to corrosion, and because of this property, it is often used to contain a variety of corrosive liquids. Lead is commonly used in building construction, paints, batteries, plumbing, ammunition and fusible alloys.

Metallic lead does occur in nature, but it is rare. Lead is usually found in ore with zinc, silver and copper, and is extracted together with these metals. Apart from how it is found naturally, lead is released into the environment by mining and smelting before it makes its way into the air, soil, and water. Lead can also remain in the environment as dust and as compounds in soil or water. Soils near roads and smelting facilities have higher