Is there a way of saying that a small change will make a big difference? The current sentence doesn't sound very good. I do not want to say something along the lines of a domino effect.
I'd say pivotal fits the bill nicely.
Extremely important and affecting how something develops.
- A pivotal moment in the history of the Egyptian state
- He played a pivotal role in the negotiations.
- A pivotal figure/player in US politics
- Pivotal to: He sees these reforms as pivotal to our economic interests in Asia.
A pin, point, or short shaft on the end of which something rests and turns, or upon and about which something rotates or oscillates.
This is nothing but the butterfly effect.
The avalanche effect is signified by making a small change with a big difference in result.
By changing one function in my code I caused an avalanche effect. The function caused a loop therefor taking down the entire website.
Also if a small change creates incremental changes that ends up being a big change, you could refer to that as the snowball effect.
A well known phrase for a small action having a wide sphere of influence (change) is the ripple effect: a spreading effect or series of consequences caused by a single action or event. One small event spreads outwards involving more and more.
Think Rosa Parks: one woman who refused to give up her seat to a white man. She was arrested. It set off a widespread dissatisfaction, turned into indignation, the Montgomery Bus Boycott, gave a relatively unknown (Rev. Martin Luther King Jr.) a Montgomery platform which lead to a nationwide platform, and gave the entire Civil Rights movement a focus, an icon, and a needed boost.
Parks' quiet yet outrageous act of civil disobedience was a stone dropped into a pool that would soon grow turbulent. Its ripple effect led to significant changes in the social fabric of the United States over the next decade and ended segregation laws in the South.
...whatever your faith, you can believe in the spirit of strength, justice, and courage that prompted one small woman to take a big risk on a crowded bus on a December evening -- a shining moment that changed the world for the better. - Rosa Parks in 1988 © Angel Franco, New York Times
Or the domino effect - one small push and everything changes.
This is something of a tangent but since two copper coins would surely count as "small change" then what Jesus was recorded as saying seems relevant ...
As Jesus looked up, he saw the rich putting their gifts into the temple treasury. He also saw a poor widow put in two very small copper coins. ‘Truly I tell you,’ he said, ‘this poor widow has put in more than all the others. (Luke 21:1-3, NIV)
This is commonly referred to as the "widow's mite" and suggests that even small change can be a valued contribution that makes a significant difference.
A more direct phrase may be something similar to, "...seemingly insignificant change..." I can't think of much else along those lines, though I'm sure others can.
Otherwise, a "single wave which became a tsunami" (though scientifically incorrect) or, "the spark that ignited an explosion" "Every (vote, penny, other object?) counts" "feather that broke the camel's back"
The icing on the cake could be a small change that makes the whole much better if its worded right.
Something that is made a big deal of even though it is a small change might be made into a mountain from a molehill.