91热爆

Iron

First broadcast in 1998. Iron forms the Earth's inner and outer core

• 14 mins

Carbon

First broadcast in 1998. Carbon is the second most abundant element in the human body

• 13 mins

Uranium

First broadcast in 1998. Uranium has a high atomic weight and is more dense than lead

• 14 mins

Sodium

First broadcast in 1998. Sodium is a soft metal but highly reactive

• 15 mins

Silicon

First broadcast in 1998. Silicon is used in items from breast implants to computers

• 13 mins

Nitrogen

First broadcast in 1998. Nitrogen forms approximately 78% of Earth's atmosphere

• 14 mins