Key Question: How do you think things like
water and food, which cells need to live, get
into and out of cells?
5 minutes
Initial Thoughts:
Paste the sheet into your notebook
• Perfume
• Food coloring and beaker
• Food coloring and graduated cylinder
• Make a prediction.
• Why did you predict what you did?
What does “concentration” mean? For example:
the concentration of salt in sea water.
Concentration: The number of “particles” in a
given space. Which is more concentrated?
OR
• Diffusion is the natural
movement of any molecule
from high concentration
(where there’s lots of them)
to low concentration (where
there’s not as much)
until they are equally spread
out.
• Diffusion of water from high to low
concentration
• Movement from high to low
concentration until they are
spread out equally in all areas
• Movement of ANY small
uncharged molecules
• Osmosis is the diffusion of
WATER.
• Osmosis – the movement of water molecules
from high concentration to low concentration
Diffusion is a slow
process because it
relies on the random
movement of atoms
and molecules.
• Diffusion & Osmosis is how things like oxygen,
food, and water get transported into and out
of cells.
• http://molo.concord.org/database/activities/2
23.html
• BrainPop
• Hypotonic:
it causes it to swells up
(think Hypo = Hippo)
• Hypertonic:
it causes it to shrivel up
(Think hyper skinny kid)
• Vinegar is an acid that will dissolve the hard
shell, leaving only the thin membrane around
the egg “cell”.
• Water is small enough that it can enter or
leave through the egg membrane.
(it is selectively permeable).
Variables:
Manipulated Variable:_____________
Responding Variable:______________
Controlled Variables:______________
Variables:
• Manipulated Variable: Type of liquid
• Responding Variables: Weight of egg and
Volume of liquid
• Controlled Variables: same egg, same amount
of time in liquid, same amount of liquid, same
cup
#1 Testable Question: What will happen when
we put an egg into corn syrup?
Hypothesis: If we put an egg into corn syrup, then
we will see....because…..
#2 Testable Question: What will happen when
we put an egg into colored water?
Hypothesis: If we put an egg into colored water, then
we will see....because…..
1. Explain why diffusion and osmosis are important
to cells.
2. Why do grocery store owners spray fresh fruits
and vegetables with water? Explain using what
you learned about osmosis.
3. If a shipwrecked crew drinks sea water, they will
probably die. Why?
Write a summary of the Egg Lab. Remember to:
1. restate your hypotheses (there were 2 in this one)
2. Tell if they were supported or not.
3. Use your data to back up #2. Tell the reader what
your numbers are, and then explain what they mean
(see #4 below)
4. Explain your data using the principles behind
Osmosis/Diffusion. Was the corn syrup and colored
water hypotonic or hypertonic?
5. Further thoughts, improvements, extensions, etc.
• Draw what happens when a fresh water fish
cell is placed in sea water, using arrows to
show the direction water is moving (in or out
of the cell).
• Cells use diffusion and osmosis to get things
like food & water into and out of cells.