The objective of this project is to
use paper chromatography to analyze the leaf pigments found in three different
types of plants.
Matter makes up everything in the
universe. Our body, the stars, computers, and coffee mugs are all made of
matter. There are three different types of matter: solid, liquid, and gas. A
solid is something that is normally hard (your bones, the floor under your feet,
etc.), but it can also be powdery, like sugar or flour. Solids are substances
that are rigid and have definite shapes. Liquids flow and assume the shape of
their container; they are also difficult to compress (a powder can take the same
shape as its container, but it is a collection of solids that are very small).
Examples of liquids are milk, orange juice, water, and vegetable oil. Gases are
around you all the time, but you may not be able to see them. The air we breathe
is made up of a mixture of gases. The steam from boiling water is water's
gaseous form. Gases can occupy all the parts of a container (they expand to fill
their containers), and they are easily compressed.
Matter is often a mixture of
different substances. A heterogeneous mixture is when the mixture is made up of
parts that are dissimilar (sand is a heterogeneous mixture). Homogeneous
mixtures (also called solutions) are uniform in structure (milk is a homogeneous
mixture). A sugar cube floating in water is a heterogeneous mixture, whereas
sugar dissolved in water is a homogeneous mixture. You will determine whether
the ink contained in a marker is a heterogeneous or homogeneous mixture, or just
In a mixture, the substance
dissolved in another substance is called the solute. The substance doing the
dissolving is called the solvent. If you dissolve sugar in water, the sugar is
the solute and the water is the solvent.
Matter is made up of small
particles called atoms. Each atom is made up of smaller, positively charged
particles called protons, neutral particles called neutrons, and even smaller
negatively charged particles called electrons. At the center of each atom is the
collection of protons and neutrons called the nucleus. Electrons spin around the
nucleus in different energy levels called orbitals. Each orbital corresponds to
a discrete amount of energy that the electron can have. A really excited
electron with a lot of energy is further from the nucleus. In the image below,
the electrons are yellow with a negative sign, the protons are green with a
positive sign, and the neutrons are red with no sign. Keep in mind that this is
a representation of what an atom looks like. Since atoms are so small, no one
has seen a full atom before with the electrons orbiting around the nucleus.