Unit A: 1.2Matter is made of atoms

•Identify the smallest particles of matter•How atoms combine into molecules

•How atoms and molecules move

Atoms

• The basic unit of matter

• All matter made of different types and arrangements of atoms

• Building blocks: atoms are the small parts that make up a larger structure.

• “Matter is not something that contains atoms. Matter IS atoms.”

Atoms• Extremely small: take above shape – pretend an

atom is blown up to this size, how large would the pin be?– It’d cover 90 mi2 (1/7 the area of London; Catalina Island

= 76 mi2), 80 miles high (15x Mt. Everest)• Too small for a light microscope• Spoonful of water contains

500,000,000,000,000,000,000,000 atoms• How to find the mass of an atom? • Find the mass of a large amount of a substance and

divide it by the number of atoms to estimate the mass of one atom– Add up mass of all atoms in the spoonful of water: m =

5g

(Unit B, Atomic Structure)

Mini-lab: How small is an atom?• How small is an atom? How small is a cell?• Investigate the world of the very small by cutting a 28 centimeter

(11 inch) strip of paper in half as many times as you can. If you can cut the strip of paper in half 31 times you will end up with a piece of paper the size of an atom!

• MATERIALS• 1 strip of paper 28 centimeters long (11" inches)• 1 pair of scissors• PROCEDURE

– Take your strip of paper and cut it into equal halves.– Cut one of the remaining pieces of paper into equal halves. (# each cut 1,

2, 3, 4…)– Continue to cut the strip into equal halves as many times as you can.– Make all cuts parallel to the first one.

How far did we get? Some comparisonsCut 1 14.0 cm 5.5" (inches) Child's hand, pockets

Cut 2 7.0 cm 2.75" Fingers, ears, toes

Cut 3 3.5 cm 1.38" Watch, mushroom, eye

Cut 4 1.75 cm .69" Keyboard keys, rings, insects

Cut 6 .44 cm .17" Poppy seeds

Cut 8 1 mm .04" Thread. Congratulations if your still in!

Cut 10 .25 mm .01" Still cutting? Most have quit by now

Cut 12 .06 mm .002" Microscopic range, human hair

Cut 14 .015 mm .006" Width of paper, microchip components

Cut 18 1 micron .0004" Water purification openings, bacteria

Cut 19 .5 micron .000018" Visible light waves

Cut 24 .015 micron .0000006" Electron microscope range, membranes

Cut 31 .0001 micron .0000000045" The size of an Atom!

Is there anything smaller?• Yes, an atom’s nucleus is ~41 cuts! Electrons are

9,000 times smaller than this! These things are far beyond the range of sensory perception, but not beyond the range of human understanding.

Molecules• What makes up substances besides

atoms and molecules?• Atoms (or combinations of atoms, molecules) are the

only matter in a substance…there is empty space between atoms but it is too small to see and has no mass

• When two or more atoms bond together– Atoms can be the same or different– Ex: water = 2 hydrogen atoms, 1 oxygen atom– Ex: hydrogen gas = 2 hydrogen atoms– Ex: Vitamin E = 29 Carbon, 50 H, 2 O

• Same atoms, different # = different substance– Oxygen (2 O O2) and Ozone (3 O O3)

• Particles + Particles = Atoms   

• Atoms + Atoms = Molecules   

• Molecules + Molecules = Matter

Motion of Atoms and Molecules• Atoms and Molecules are constantly

– in motion

– colliding with other atoms and molecules

• Not as obvious with solids, but they are still moving…• States of matter 1.4