A firefly and you are built from the same small handful of pieces. Here's how they stack up, from the atom to the four kinds of molecules that make up every living thing.
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Students will learn how atoms build up into elements, compounds and molecules, and then see how the compounds in living things divide into inorganic and organic.
Matter is anything with mass that takes up space. It is made of atoms, and an element is one kind of atom. When atoms of two or more elements bond together they make a compound, and the smallest piece of a compound that still acts like it is a molecule.
Compounds in living things come in two families. Organic compounds contain carbon and make up foods and cell membranes, and they fall into four groups: carbohydrates, lipids, proteins and nucleic acids. Most inorganic compounds are made from elements other than carbon, and water is the most important one.
Keep the ladder in order: atom, element, compound, molecule. A student who has the order can rebuild any definition from it.
Water is the example the book uses to hold the whole lesson together, so come back to it every time a new word appears.
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Before You Start
The words this lesson uses. Tap a card to see what it means, then come back to them whenever a question uses one.
Part One
Questions about the story you just read. Pick your answer straight off, or press Find it in the story if you would rather hunt for the sentence first.
Part Two
The word cards are at the top of this page. Look back at them as often as you need, then answer.