Simplify the following text for a Grade 9 native English-speaking person.
Original: Consumable electrode processes such as shielded metal arc welding and gas metal arc welding generally use direct current , but the electrode can be charged either positively or negatively . In welding , the positively charged anode will have a greater heat concentration , and as a result , changing the polarity of the electrode has an impact on weld properties .
Simplified: Because the electrode is consumed by the welding process , the electrode must constantly be fed into the weld .