How do I get more equidistant barlines?

Is there a way to set a score so that the distance from barline to barline is as near as possible to being constant?

And secondly, can I add lyrics without the distances becoming very uneven again?

I have just presented a piece to children and one thing that confused them was that one stave had just one bar in it whereas the next stave had three in it, the difference being particularly confusing because of the lyrics.

Thanks in advance.