Physics
Momentum Conservation
Quick fact
The conservation of momentum is a direct consequence of Newton's third law: for every action, there is an equal and opposite reaction. No external force means total momentum stays the same.
Why this is interesting
Have you ever wondered why a cannon recoils backwards when it fires a cannonball forward, or why a figure skater spins faster when pulling their arms in? The answer lies in a hidden quantity that nature insists on keeping constant: momentum.