During puja ritual a lamp is offered at various steps of the ritual according to purpose. For example performance of arti. Two types of wicks are used in the lamp namely Puffed wick and straight wick. Nowadays a puffed wick is used in a ghee lamp or niranjan and used as lamp of worship. The wick is puffedup from below to offer it stability to stand in the center of niranjan. The puffed wick is used in a ghee lamp. This type of wick is relatively of recent origin.The second type of wick which we all are familiar with is straight wick. Two straight wicks are joined together like a thread and used in a lamp. Not only there is difference between the two on a gross form but also on spiritual level.
• The lower portion of the fulwat is puffed up while the straight wick is whole like a thread.• The fulwat is representative of various raja thoughts in the mind while straight wick is symbolic of detachment and also represents the thread which joins Panchaprans with Atamjyoti.• When a fulwat is kindled the inferior deities are attracted to it while the straight wick when kindled attracts principles of higher deities.• The frequencies emitted by the fulwat are of circular form while those emitted by straight wick are in the form of waves.

• The colour of the divine consciousness emitted by the fulwat is redish yellow while that emitted by straight wick is of yellow colour.

• Sattvik earth frequencies get attracted towards fulwat while more sattvik frequencies moving in the upward direction are attracted towards straight wick.

• The atmospheric frequencies get momentum due to fulwat while their momentum is slowed down by the use of straight wick.

• An armour of Pruthvi (absolute earth element) and Aap tattva (absolute water element) is generated around the worshipper by use of fulwat while straight wick generates an armour of Tej tatva (absolute fire element) around the worshipper.
According to science of spirituality Tej tattva is more powerful than either Pruthvi tatva or Aap tattva. As a result the use of fulwat imparts heaviness to the physical body while the use of straight imparts cheerfulness to mind.
Thus we have seen the difference between the fulwat and straight wick and also why it is important to use straight wick.
courtesy : www.hindujagruti.org