When you whip egg whites, you're creating a network of bubbles that get trapped in a mesh of protein. It's like a tiny, edible game of Jenga! As you add sugar, it helps to strengthen this structure, making it more stable. But if you're not careful, it can quickly become a soggy mess.
To avoid this, you need to stabilize your meringue with a little help from some trusty friends: cream of tartar and salt. These guys help to strengthen the bonds between the egg whites and sugar, making it more resistant to collapsing. It's like having a team of tiny, molecular bodyguards!