Science Focus Lesson
SC.5.P.8.3
Mixtures
Polk County Public Schools
SC.5.P.8.3
Benchmark: Demonstrate and explain that mixtures
of solids can be separated based on observable
properties of their parts such as particle size, shape,
color, and magnetic attraction.
Essential Question:
How can mixtures be separated?
Vocabulary:
mixture
dissolve
physical properties
Physical Properties of Matter
Matter – everything that takes up space and has mass.
Let’s look at some physical properties of matter that you
can observe:
SIZE
MAGNETIC
ATTRACTION
SHAPE
VOLUME
COLOR
SINK/FLOAT
Mass, density, texture, ability to
transfer heat and electricity,
ability to bend and transparency
are more examples of physical
properties of matter.
A mixture is when two or more substances are physically but NOT
chemically combined and can be separated again.
The substances in a mixture are not permanently combined, and their
properties don’t change. They can be separated(taken apart) from each
other again. The change can be reversed. A new material is not formed.
Sometimes it’s easy to see the parts of a mixture. If you mix sand and water
and shake it up, the water looks cloudy. If you let the sand and water
mixture sit for awhile, the sand will fall to the bottom.
Granola
Sand & Coins
Water & Sand
Metal & Sand
Salad
These mixtures can be easily separated.
Minerals
At other times, it is hard to see the parts that were mixed. If you mix salt
with water and shake it up. The salt dissolves. It will not fall to the
bottom. This kind of mixture is called a solution.
Dissolve means to form a solution with another substance. The
substances are spread out evenly and you cannot see the separate
substances in this mixture.
Salt Water-Ocean
Food Coloring & Water
Water & Salt
Lemonade
Coffee
Water & Sugar
These mixtures cannot be separated easily.
With your shoulder partner, complete the following 3-2-1
summary:
3 – Name and discuss 3 physical properties
of matter
2 – Name and discuss 2 mixtures. Choose 2 that are
easily separated
1 – Name and discuss 1 mixture that is not easily
separated. Include the word dissolve in your
discussion
How can we separate mixtures?
You now know that some mixtures are easy to separate and some
are not. For example, you can separate the cereal from the milk
by passing it through a strainer. The cereal pieces would get
“caught” in the strainer while the milk would pass through the
holes. Separating the salt from salt water would be
much more difficult.
Forceps
Other tools you may use to separate
mixtures are shown here. Think
about which one you might use to
separate the salt from the salt
water.(collaborative pairs discuss)
Share your answer.
Strainer
Magnet
Funnel & Filter
Heat for evaporation
Talk to your shoulder partner and decide how you would
separate the substances in these mixtures.
Tools
Mixtures
sand and water
oil and water
iron filings and sand
trail mix
Salt and water
Forceps
Sieve
Heat or
evaporation
Funnel with filter
magnet
How can we speed up or slow down how a material
dissolves in water?
1.
Temperature – if you increase the temperature of the water by heating it
up, the material(salt, sugar, etc.)will dissolve FASTER because molecules
move faster in hot water than in cold.
2.
Stirring – if you stir the mixture, the material will dissolve
FASTER because the particles will connect faster with all
the movement the stirring causes.
3.
Surface Area – if you take two of the same size sugar cubes and put one
of the cubes in water and then divide the other sugar cube into 4
pieces(increasing its surface area) and put it in a different container of
water, the 2nd cube will dissolve FASTER because it had more surface
area than the cube that wasn’t divided up in pieces.
ROUND TABLE:
Starting with the shortest person in your group,
name and discuss the 3 conditions that speed up
the dissolving process. If there is a 4th person in
your group, they have to review all 3 conditions
again for the group.
Guided Practice
Work with your shoulder partner to answer each question
1. Kate had two cups of water. She added a tablespoon of sugar to one
cup and mixed it. She put a tablespoon of sand in the second cup
and mixed it. What happened to the sugar and sand when Kate
mixed them with water?
A. The sand dissolved forming a solution; the sugar did not dissolve.
B. The sand dissolved forming a solution; the sugar evaporated.
C. The sugar dissolved forming a solution; the sand did not dissolve.
D. The sugar melted; the sand did not melt.
Kate observed that the sugar
dissolved but the sand did not.
Guided Practice
2. Juan was hungry. He put cheese, ham, tomato, and
pickle on a slice of bread. He folded the bread in half
and ate it. Which of the following describes what Juan
made when he combined all these ingredients?
A. a solution
B. a change of state
C. a chemical change
D. a mixture
Juan made a mixture when he
combined the ingredients.
Guided Practice
3. Joey’s teacher asked him to combine several
substances to make a solution. Which picture shows
what Joey made?
A.
B.
C.
D.
Joey made lemonade. The sugar and
flavoring dissolved in the water to make
a solution.
With your shoulder partner, write the
definition of dissolve and make a list of
common materials that will dissolve in
water and those that will not.
Check Your Understanding
Record your answers. Check them at the end.
1. Sam made iced tea for his mom. He added sugar. The
sugar was at room temperature. He stirred the iced tea
until the sugar dissolved. Which property of sugar
stayed the same when Sam added sugar to the iced
tea?
A .taste of the sugar
B. grains of the sugar
C. temperature of the sugar
D. texture of the sugar
Check Your Understanding
2. Which of the following lists of materials would ALL
dissolve in water?
A .salt, oil, chalk, flour
B. salt, soil, sand, sugar
C. salt, sugar, coffee, flour
D. salt, pepper, sugar, oil
Check Your Understanding
3. If your science teacher asked you to separate a mixture
of sand and iron filings, which would be the best
method to use?
A . Use tweezers
B. Use a magnet
C. Use a filter
D. Use evaporation
Check Your Understanding
4. Which action below would be the fastest way to
dissolve a sugar cube in a cup of water?
A . Put the cup in the refrigerator
B. Let the cup sit still for 10 minutes
C. Add more water to the cup
D. Break the sugar cube up into smaller pieces
before putting it in the water
Check Your Answers
1. A
2. C
3. B
4. D
Write a summary paragraph explaining
what you know about mixtures and
how they can be separated. Include the
following vocabulary: physical
properties, mixture, dissolve.