2. What is the difference between a mixture and a compound?
Chemical Relations
What is the difference between a mixture and a compound?

3. Chemical Relations
Elements
combine

7. separating with hands
straining
filtering
evaporating

8. Chromatography- the science of separating colors.

9. Brass- an alloy of copper and zinc.

12. Read online article on science site on mixtures.
Add additional information to your 
class notes.
Complete the worksheet Chemical 
Relations 1-12 for homework.
Eat fruit cocktail!!

13. Why do some things float
and some things sink?

14. Light bulbs contain a 
partial vacuum, usually 
backfilled with argon, 
which protects the 
tungsten filament.
Single-barrel vacuum 
pump milking machine

15. The pressure pushing up on 
an immersed object is 
greater than the pressure 
pushing down on it. This 
difference results in the 
buoyant force.
Weight is a force in the downward 
direction. The buoyant force is in 
the upward direction. An object 
will float if the upward force is 
equal to the downward force.

16. the buoyant force on an object in a
Archimedes, a Greek 
mathematician who lived in the 
third century B.C., made a 
discovery about buoyancy.  
According to Archimedes’ principle,
the buoyant force on an object in a
fluid is equal to the weight of the
fluid displaced by the object.
If you place a block of pinewood in water, it will push water 
out of the way as it begins to sink-but only until the weight of 
the water it displaces equals the block’s weight.
The block floats at this level.

17. The amount of buoyant force determines 
whether an object will sink or float in a fluid.
If the buoyant force is
less than the objects weight,
the object will sink.
If the buoyant force equals or is greater the 
objects weight, the object floats.

18. Sometimes the buoyant force on an object is greater 
than the weight.
This force is what seems to
pull a helium-filled balloon
upward in the air.
When the balloon is released,
the unbalanced buoyant force
causes the balloon to accelerate upward.

19. Mixtures: Homogeneous & Hetergeneous
THINK, THINK, THINK
Archimedes' Principle
and
Buoyancy Force
Mixtures: 
Homogeneous & 
Hetergeneous

21. Separating Mixtures
Mixtures are separated by taking advantage of differences in the 
properties of the substances that make up the mixture. There 
are many ways to separate mixtures, as we have discussed in 
class. Discuss with your partner some ways to separate a 
mixture. Observe the plastic beads on the lab table and suggest 
some ways to separate the beads into groups.
Today we are going to separate a mixture by using density. 
Everything has its own characteristic density, just as the 
colored plastic pieces have. Follow the procedure below to 
easily separate the different pieces from each other.

22. Procedure:
Put a sample of the mixture (about a tablespoon) into a 250 mL beaker.
Add water until the beaker is about half full. Stir the mixture so that any plastic piece 
that ends to float will not be held down by other pieces. (Sometimes small objects 
may float even though their density indicates they shouldn’t. Air bubbles and the 
water’s surface tension may keep objects afloat that should sink. Force the plastic 
pieces under the water to make sure only the pieces with a density less than water is 
floating.)
Only one kind of plastic piece should be floating. Use the spoon to remove them and 
place them in one of the small cups provided.
Change the density of the water by pouring out about half the water into the water 
supply, and refill the 250 mL beaker about half way with the salt solution. Stir 
carefully and observe.
Remove the colored particles that are floating and put them into a small cup.
Add a measure of salt to the beaker and stir well. Remove the floating particles and 
put them into a small cup.
Strain the material in the cup and collect the last set of objects from the cup.
Put all your plastic pieces into the strainer that is provided, and rinse carefully with 
pure water. Drain well. Put the plastic pieces back in their original container, clean off 
table and sit down.

23. Particles are denser than the fluid, they all sink.
D
E
N
S
I
T
Y
Particles are denser than 
the fluid, they all sink.
Red articles are less dense than 
the fluid, they float, while the other 
particles all sink.
Blue particles are suspended 
in the fluid. They are equal in 
density to the fluid.
Blue, red and green particles are 
less dense than the fluid. The black 
particle is more dense than the fluid.

24. Also read Lab Procedure for tomorrow.
THINK, THINK, THINK
READ, HIGHLIGHT, LEARN
Archimedes' Principle
and
Buoyancy Force
Packet
Also read Lab Procedure for tomorrow.

25. PLease place your outdoor observation project on the correctly numbered lab table. Be sure your self evaluation sheet is included.

26. The density of the fluid is less than 
the density of the beads.
All the beads are on the bottom of 
the beaker, because they are more 
dense than the fluid.
The buoyancy force is greater 
pushing down than pushing up so 
all the bead sink.

27. The red beads are less dense 
than the fluid, while the blue and 
green beads are more dense.
Anything less dense than the 
fluid will float.
The buoyancy force pushing down on the 
red beads is less than the force pushing up 
so the beads float.
The force pushing down on the blue and 
green beads is greater than the upward 
force, so these beads sink

28. The blue beads are suspended 
in the fluid.
The density of the blue beads is 
equal to the density of the fluid.
The green beads are more 
dense than the fluid and are on 
the bottom of the beaker.