I am trying to create a project in which I need to increase and decrease the length of a sprite i.e. a rod.
can we do that in scratch?
please help!

You can use the Size blocks although the width of the rod will change as it gets longer.

only the length of the sprite must change.not along with its breadth.

IndianCircus wrote:

only the length of the sprite must change.not along with its breadth.

Not possible using a single sprite costume. You can only change the size in both dimensions.

dogman785 wrote:

Please don't spam or necropost.

@OP, if you're still looking for an answer:
To my knowledge, there's no way to stretch a sprite in one direction using Scratch blocks. However, you could try animating the stretching-out using multiple costumes or rendering the bar using stamping or pen.