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Name
Class
Date
2A
ñ
mrn
Diffusion in Action
Diffusion refers to the intermingling of substances by the natural movement
of their particles. In this activity, you will see how diffusion works by observing
water and food coloring.
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Procedure
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2.
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Materials
Fill the clear plastic cup with cold water. Place the cup
on the table and allow it to sit untilthere is no movement in the water.
l$ tlw"", a lab apron to protect your clothes and
gloves to protect your hands. Use a plastic dropper to
add one large drop of food coloring to the water.
clear plastic cup
food coloring
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cold water
plastic dropper
clock or watch
3. Check the time. Observe the water every minute.
Record any changes that take place at the beginning
of each minute. Continue to observe until you can no
longer see any changes.
Think lt Over
0
Write an explanation for the changes you observed.
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How would the results be different if you used a larger am¡runt of water? What do
you think would happen if you used hot water?
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More water- more time for diffusion
Hot water- it would go faster. warm molecules move faster.
THË CËLL IN ITS ËNVIRONMENÏ
Copyright O Pearson Education, lnc., or its affiliates. All Rights Reserved
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TJ
il
Class
Date
Name
The Cell in lts Environment
¡
lnquiry Warm-Up, How Do Molecules Move?
ln the lnquiry Warm-Up, you investigated how molecules spread l¡om one point. Using
what you learned from that activity, answer the questions below.
1.
.
oBSERVE How long did it take for the food coloring to spread
through the water?
About 4 minutes (you should have accurate data here!)
2. cALcuLlte Assume that there is one cup
of water in this experiment
How long would it take one drop of food coloring to spread
throughout in four cups of water?
4 times as long (assuming you had about 4 minutes in question 1 it would take 16 minutes)
3. cntpn
Draw a graph that shows the relationship between a time and
the spreading of the food coloring.
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4.
coNTRoL vARIABLES lf you had used a cup of ice water, would the food
coloring have spread faster or slower? Explain.
Ice water would make it go slower because cold molecules travel slower.
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I
Copyright @ Pearson Education, lnc., or its affiliates. All Rights Reserved
lesson 1.4 Reading
Read pages 29-33 and
fill in the table below
as you go
Plcture
Word
Selectively Permeable
Definition
Passive Transport
The movement of dissolved materials
across a cell membrane without using
cellular energy.
the process by which molecules move
from an area of higher concentration
to an area of lower concentration.
some substances can move across
the membrane while others cannot.
Diffusion
Osmosis
the diffusion of water molecules
across a selectively permeable
membrane.
Active Transport
movement of materials across a cell
membrane using cellular energy.
Endocytosis
the cell membrane changing shape
and engulfing the particle.
Exocytosis
allows large particles to leave the
cell.
Molecules move into and out of a cell by means of passive or active transport.
L. Fill in the words missing in the boxes.
2. On the diagram, write an "H' where the concentration
(amount) of each substance is high and
an "L" where the concentration is low.
Passive
diffusion
osmosis
o
LOW
Active
Trrnrport
Trmrport
Frcilitatod
diff¡¡¡ion
I o
HIGH
lnlde a
ol cdl
o .O¡
I
I O¡
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HIGH
Outrldr
'ol crll
LOW
Lesson
1.4 Notes
Class
Date
Name
The Cell in lts Environment
How Do Materials Move lnto and Out of Cells?
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1a. nevlrw Use diffusion to tellwhat happens when you drop a sugar
cube into
¡
water.
The sugar molecules move evenly from the high concentration (of the sugar cube) to the lower concentration
of the water.
b. pREDtcr Draw an arrow to show the overall direction water will
travel as a result of osmosis. (The vertical line is a cell membrane.)
trt/atei'
rno[ecu?e
c. IDENTIFY Active transport depends on (sugarsiproteins) to move
molecules across the cell membrane.
d. colrlpnnE AND coNTRAST Give an example of how active transport
differs from passive transport.
Active transport requires energy from the cell whereas passive transport does not.
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move substances into and out of the cell.
I get it! Now I know that a key function of the cell membrane is
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I need extra help with
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