Transcript Chemical/Physical Changes

Physical
or Chemical
Change?
Chemistry
1.
Chopping wood
(Chopping = cutting into large
pieces)
2.
Wood becoming sawdust
(Sawdust is the small particles of
wood that fall to the ground when
you cut wood.)
2.
Physical change…
because the bits of dust
are STILL made of
WOOD.
1.
Physical change…
because after the wood
is chopped, it is STILL
made of WOOD.
1.
2.
Burned logs
2.
Sugar dissolved in water
(Dissolved = melted. When sugar
dissolves in water, you cannot see
the sugar anymore, but it’s there.)
Physical change…
because the sugar still
exists; it is just broken up
into bits in the drink.
1. Chemical change…
because the wood turns into
smoke & ash. It cannot be
changed back into WOOD.
1.
2.
Salt and pepper
mixed together
Physical change…
because the substances have NOT
changed into new substances.
2.
Putting salad dressing
on salad
1.
Physical change…
because the salt and
pepper still exist; they
are just mixed with
each other.
1.
2.
Fruit salad tossed together
(“Tossed together” = mixed
together)
2.
Rusting bike
(Rust occurs when metal reacts
with oxygen. The oxygen is
destroying the metal and breaking
it down into very small pieces.)
Chemical change…
because the metal is
CHANGED into a NEW
substance called
RUST.
1.
Physical change…
because the fruit has
not changed into
different substances.
Gasoline burning
(Inside an engine, gasoline
burns (combusts) to produce
energy so the car can go.)
1.
2.
Liquid water freezing
(Liquids freeze when they get cold
and turn into a solid.)
2.
Physical change…
because the
substance is STILL
water, even though
it’s frozen solid.
1.
Chemical change…
because when
something BURNS, it
turns into NEW
substances like smoke
and smog.
1.
2.
Rocket fuel igniting
(Ignite = to start a
fire. When rocket
fuel burns, it
produces energy to
make the rocket
go.)
2.
Ice melting
(Something melts when it
changes from a frozen solid to
a liquid.)
Physical change…
because it is STILL
made of the same
substance (water).
1.
Chemical change…
because when
something burns, it
turns into NEW
substances like smoke.
1.
2.
Minerals forming
(Minerals form deep within the
earth when certain elements
are changed due to the intense
heat and pressure inside the
earth.)
Glaciers melting
2.
Physical change…
Because it’s STILL
all water…nothing
new is made.
1.
Chemical change…
because NEW
substances are made.
plants decomposing
1. Dead
(Decomposing = the nutrients from
2.
something that was once alive, but
now is dead, are going back into
the ground and can be used again
by other plants.)
Chemical change
2.
Silver tarnishing
(Tarnish forms on silver when the
silver reacts with the oxygen in
the air. It forms a greenish-black
substance on the silver that can
be removed with special polish.)
1.
Chemical change
1.
2.
Firecrackers exploding
Physical change
2.
Ocean water evaporating and
leaving salt behind
(Evaporation occurs when water
molecules float up into the air to
form clouds. Anything that was
in the water will stay behind.)
1.
Chemical change
1.Saliva dissolving starch in food
(Saliva = the water your mouth
produces. To dissolve = to
break down into very small
pieces using water. Starch =
carbohydrates, a type of energy
in food.)
2.
Saliva breaking the chemical bonds
of meat protein
(The liquid in your mouth reacts
with the meat to separate the
protein so your body can absorb it.)
2.
Chemical change
1.
Chemical change
1.
A tree’s leaves changing color in the
fall
(The leaves turn color because they
are dying.)
2.
2.
Physical change
1.
Glass breaking
Chemical change
1.
2.
Baking Bread
Physical change
2.
1.
Paint Drying
Chemical change
1.
Making Kool-Aid
2.
Chemical change
2.
1.
Milk souring
Physical change
Good
→
Bad
1.
A rotting log
2.
Physical change
2.
Making an ice sculpture
1.
Chemical change
1.
Burning a candle
2.
Chemical change
Penny turns green
2.A
(Pennies are made of the element
copper. Copper reacts to oxygen in
the air by forming a green or brown
coating.)
1.
Chemical change
1.
An Alka-Seltzer in
water
(When the
chemicals in the
medicine combine
with the water,
carbon dioxide gas
is released and the
medicine dissolves
into the water.)
2.
Tearing a piece of paper in two
2.
Physical change
1.
Chemical change
1.
Reacting substances
2.
Physical change
2. Mixing blue and red paint to make
purple
1.
Chemical change
+
=
1.
A magnet sticking to a refrigerator
heat or electricity
2.Conducting
(The eye on the stove conducts
(carries) heat to the pan, and the pan
conducts heat to the food. The
molecules in air conduct (allow to
travel) lightening.)
2.
Physical change
1.
Physical change
1.
Cooking pancakes
2.
THE END
2.
1.
That’s all.
Chemical change