Science 2 Reviewer

1) Matter

Definition: Anything that has weight and takes up space.

Examples (10): water; air; rock; book; table; juice; milk; chair; food; ball

2) States of Matter

Solid — has a definite shape and size

Examples (10): book; table; chair; pencil; rock; bag; phone; shoes; cup; toy

Liquid — takes the shape of its container

Examples (10): water; milk; juice; oil; coffee; tea; vinegar; soda; soup; lotion

Gas — no definite shape or size; spreads out

Examples (10): air; oxygen; carbon dioxide; helium (balloons); water vapor/steam; perfume smell; natural gas; car exhaust; breath; wind

3) Characteristics of Matter

Malleable — can be hammered/pressed into a new shape

Examples (10): clay; play dough; aluminum foil; copper sheet; gold; silver; modeling wax; putty; bread dough; soft plasticine

Elastic — can stretch and return to original shape

Examples (10): rubber band; balloon; coil spring; hair tie; elastic waistband; bungee cord; slingshot band; silicone wristband; exercise resistance band; trampoline mat

Viscous — thick liquid that flows slowly

Examples (10): honey; maple syrup; molasses; glue; motor oil; shampoo; liquid soap; lotion; thick paint; chocolate syrup

Brittle — breaks or shatters easily

Examples (10): glass; chalk; ceramic plate; cracker; cookie; dry twig; seashell; dried clay; hard candy; potato chip

Flexible — bends easily without breaking

Examples (10): rope; rubber hose; cable wire; plastic straw; bendy straw; thin plastic ruler; cloth; pipe cleaner; rubber glove; jump rope

4) Changes in Matter

Physical Change — size/shape/state/appearance changes; no new substance

Examples (10): molding clay; tearing paper; folding clothes; melting ice; freezing water; stretching a rubber band; crumpling foil; cutting vegetables; sharpening a pencil; evaporating water (wet clothes drying)

Chemical Change — a new substance is formed; hard to reverse

Examples (10): burning paper → ash; rusting iron; frying an egg; baking a cake; cooking rice; souring milk; burning wood → charcoal/smoke; decaying leaves; molding bread; fireworks burning

5) Observation Guide — “What changed?”

PHYSICAL CHANGES (no new substance)

Change in Size (10): cutting paper; chopping carrots; slicing an apple; trimming nails; sawing wood; breaking a stick; grinding pepper; grating cheese; cutting cloth; crushing a can (without tearing it)

Change in Shape (10): molding clay into a ball; folding paper; crumpling paper; kneading dough; stretching a rubber band; twisting a towel; rolling dough into a log; bending a soft wire; shaping putty; making a paper airplane

Change in State (10): ice melting to water; water freezing to ice; puddle evaporating; steam condensing on a cold glass; butter melting; juice freezing into popsicles; wax melting and solidifying; dew forming on grass; frost forming on a cold surface; ice cream melting

Change in Color (still physical—mixing/coating/appearance) (10): adding food coloring to water; mixing blue and yellow paints to make green; coloring paper with crayons; painting a chair; adding chocolate syrup to milk; diluting juice (lighter color); tie-dyeing a shirt; coating wood with varnish; mixing colored sand; placing colored cellophane over a flashlight beam

Change in Texture (10): sanding wood (rough→smooth); grinding rice to flour; crushing cookies to crumbs; mashing banana; pounding peanuts; grating coconut; whisking cream to make it thicker; stirring oatmeal until smooth; shaving chocolate into flakes; erasing pencil marks (surface changes)

CHEMICAL CHANGES (new substance formed)

Change in Color (10): iron turning reddish-brown (rust); banana browning; toast darkening; meat browning when cooked; leaves turning brown/yellow as they decay; silver tarnishing; copper turning green (patina); onions turning golden when fried; cookies turning golden brown; sugar turning brown when caramelized

Change in Smell (10): milk turning sour; garbage rotting; cooking fish smell; burning paper smell; spoiled fruit odor; bread molding smell; vinegar + baking soda (faint vinegar smell remains while reaction occurs); fermented dough smell (yeast); burnt toast smell; burned plastic smell

Gas/Smoke/Bubbles Produced (10): vinegar + baking soda → bubbles; lemon juice + baking soda → bubbles; antacid tablet in water → bubbles; yeast dough rising (CO₂); burning wood → smoke; burning candle → CO₂ and water vapor; fireworks → smoke/gases; decomposition of food waste → gas; rust remover reacting with rust (bubbling) ; sparkler burning → smoke

Heat/Light Produced (10): candle burning (light/heat); wood fire (light/heat); gas stove flame; fireworks (light/heat); glow stick (chemical light); charcoal burning; kerosene lamp; matchstick burning; hand warmer (iron oxidation heat); campfire cooking flame