If you're not entirely sure what the difference between simmering and boiling water is, this analogy will give you a much better idea.
Photo by Stacy Spensley.
Scientifically speaking, simmering is when your water is roughly 94 degrees Celsius. Water starts to full-on boil at around the 100 degree point, depending on your elevation. If a recipe calls for simmering, boiling will likely be too harsh and ruin your food, so it's important to know the difference. If you don't have a thermometer, however, it can be a little tricky to determine. Fortunately, this great analogy that appeared on The Kitchn can help you to figure it out:
When I taught cooking classes I always told my students that a simmer was like an occasional giggle with the bubble occasionally bursting forth. But a rolling boil was like a full blown belly laugh. Students never forgot that analogy.
So is your water laughing uncontrollably? Or just giggling occasionally? It might seem a little silly, but this little trick can keep your cooking on track.