Described as the worlds first ionised Christmas tree, the Singing Christmas Tree has become the major attraction for both adults and kids at Sydney's award winning Powerhouse Museum this Christmas.

The tree is shaped by more than 50 lineal metres of hand-worked glass, and stands over 4 metres (14 ft) high and 5 metres (16 ft) wide.

The decorations are filled with gases such as argon, xenon, krypton, neon and helium. When the gases are activated, they cause the decorations to glow and flash. When touched, they activate choral voices so the tree can sing in rich harmonious tones.

Behind its dazzling decorations is the most common state of matter in the universe: Plasma. When energy is introduced into a gas, electrons are separated from the atoms and molecules to become positively charged ions. These charged ions go to make up the plasma. During the excitation process, electromagnetic radiation (such as visible light) is given off, resulting in the dramatic effects of the ionised Christmas tree.

Visitors to the museum create their own plasma effects by touching the glass tubing and various displays decorating the tree. The decorations have been hand worked and blown into electronic icicles, plasma baubles, snowflakes and many other gas discharge displays based on traditional Christmas Tree decorations.

As if that weren't enough, electronic devices monitor the gas discharges for any changes caused by visitor interaction. Information about the changes is sent back to to central control units. In this way, visitors are able to control sounds and lighting effects by interaction with the tree.

Before you get the wrong idea, these are not just random sounds! The tree produces a full range of rich choral harmonies and a variety of accompanyments including wind chimes and bamboo flutes. The sounds are stored in a modified KORG M1 synthesiser whilst other computerised control equipment controls changes in pitch, decay and other sound properties. Another control unit monitors three large plasma touch panels at the base of the tree. This control unit makes sure that the variuos different sounds always blend together harmoniously - avoiding poor combinations of voices in different pitches.

Dr Jesse Shore, Science Currator at The Powerhouse Museum, commissioned a Sydney design group, the Studio of Arts And Sciences, to design and create the tree which is sponsored by Hardie Industries.

In the words of Doctor Shore, "The tree shows how a marriage of Art and Science can produce a truly wonderful experience for all."

Definitely a MUST to take the kids to this Christmas!