6th Grade · Science · Reading Passage · shared by Luke Morgan
Explore chemical digestion with this 6th Grade Science reading passage on The Cracker Experiment, covering starch, enzymes, and maltose.
Have you ever wondered why a plain saltine cracker can start to taste sweet if you chew it for a long time? This common classroom experiment shows how your body begins to break down food right in your mouth. When you first bite into a cracker, it tastes rather plain and salty. But if you keep chewing it slowly, without swallowing, you might notice a surprising change in its flavor. The cracker gradually becomes noticeably sweeter the longer it stays in your mouth.
This interesting change happens because of a special process called chemical digestion . Crackers, like many other foods such as bread and potatoes, contain a complex carbohydrate called starch . Starch is made of many sugar units linked together in long chains, but it doesn't taste sweet on its own. Your body needs to break these large starch molecules into smaller, simpler sugars before they can be absorbed and used for energy. This is where the magic of your saliva comes in.
Your saliva, which is the watery liquid in your mouth, holds tiny helpers called enzymes . These enzymes are special proteins that speed up chemical reactions in your body. One important enzyme found in your saliva is called salivary amylase . As you chew the cracker, your saliva mixes thoroughly with the food. Amylase then starts to break apart the long chains of starch molecules.
The amylase enzyme specifically breaks the bonds holding the starch units together. It chops these long, complex starch chains into smaller, simpler sugar molecules. These smaller sugar units are called maltose . Unlike starch, maltose is a type of sugar that tastes sweet. So, as the amylase in your saliva works, more and more starch turns into maltose, and that's why the cracker starts to taste sweet in your mouth. This initial breakdown is just the first step…