EGG LAB 2013: AN EGGCELLENT OSMOSIS LAB

Purpose:

·  to observe results of passive transport through a cell membrane.

·  to identify isotonic, hypotonic and hypertonic solutions.

Materials: raw egg with shell, beaker, overflow can, graduated cylinder

vinegar (95% water), corn syrup (20% water), distilled water (100% water)

Procedures: check off each step as you finish it.

Day 1:

___ 1. Use the overflow can and graduated cylinders to measure the volume of the egg. Record the

volume of the egg (with units).

___ 2. Measure 120 mL of vinegar and place in beaker. Carefully place egg in the beaker as well.

Record the amount of vinegar added.

___ 3. Observe the egg in the vinegar for a few minutes. Record your observations.

___ 4. Use masking tape to label the beaker with your names, class period and date. Cover the

beaker with plastic wrap and secure with a rubber band. Place labeled beaker in cabinet.

___ 5. Rinse graduated cylinders with water. Place all cleaned materials on blue tray. Wash your

hands and return to your seat.

Observations: / Volume: _____mL

DAY 2:

___ 1. Observe the egg and vinegar. Record your observations of both the egg and the vinegar.

___ 2. Explanation #1: explain what has happened to egg and WHY.

___ 3. Use the graduated cylinder to measure the volume of the vinegar. Record the volume then

discard the vinegar in the sink.

Observations: / Volume:
vinegar _____mL
egg _____mL
#1:
#2:

___ 4. Gently take the egg out of the beaker. Use the graduated cylinder and overflow can to

measure the volume of the egg. Record. Return the egg to the beaker. #2: Explain what

has happened to the egg and vinegar volumes and WHY.

___ 5. Rinse the graduated cylinder(s).

___ 6. Measure 120 mL corn syrup with the graduated cylinder. Pour the last 10 mL SLOWLY

because corn syrup tends to “grow” after you stop pouring.

___ 7. Pour the corn syrup over the egg in the beaker. Observe the egg and corn syrup for 1 minute

and record your observations. Cover the beaker with plastic wrap and place it in cabinet.

___ 8. Use brush and soapy water to thoroughly clean the graduated cylinder. Return the supplies

to the plastic box and wash your hands.

DAY 3:

___ 1. Observe the egg and corn syrup and record your observations.

___ 2. Measure the volume of the corn syrup with the graduated cylinder. Record the volume then

discard the corn syrup and wash the graduated cylinder thoroughly with a test tube brush.

___ 3. Gently take the egg out of the beaker. Measure the egg volume using the overflow can and

graduated cylinder. Record the egg volume then return egg to the beaker. #3: Explain what

has happened to the egg and corn syrup volume and WHY.

Observations: / Volume:
corn syrup _____mL
egg _____mL
#3:

___ 4. Measure 120 mL water and pour over egg in beaker. Observe the egg and water and record

your observations. Cover the beaker with plastic wrap and return to cabinet.

___ 5. Wash your hands and return supplies.

DAY 4:

___ 1. Observe the egg in water and record.

___ 2. Measure the volume of the water and record. Discard the water.

___ 3. Remove the egg from the beaker. Measure the egg volume using the overflow can and

graduated cylinder. Record the egg volume. #4: Explain what has happened to egg and water

volume and WHY.

Observations: / Volume:
water _____mL
egg _____mL
#4:

___ 4. Clean graduated cylinder and beaker thoroughly. Discard egg and plastic wrap. Return

supplies.

ANALYSIS:

TABLE 1

Egg Volume (mL) / Change in egg volume from egg volume at beginning of lab
(+/- mL)
Beginning of lab (Day 0) / XXXXXX
When removed from vinegar (Day 1)
When removed from corn syrup (Day 2)
When removed from water (Day 3)

TABLE 2

Solution in beaker / Amount added to beaker (mL) / Amount removed from beaker
(mL) / Change in amount (+/- mL)
Vinegar / 120 mL
Corn syrup / 120 mL
Water / 120 mL

1.  Make a LINE GRAPH of egg volume (y) versus time (x). Label the axes and include units. Make a title for the graph. Label the line to indicate where you changed solutions.

2.  CONCLUSION QUESTIONS: Answer with complete sentences on back of graph paper.

a.  In this experiment, what was the independent variable? dependent variable? control?

b.  What was the purpose of the vinegar? What evidence do you have in your data for to support your answer?

c.  What changes did you observe in the volume of the egg and the vinegar (include your data)? Explain your observations. What happened to the egg and vinegar?

d.  What did you observe about the volume of the egg and the corn syrup (include your data)? Explain your observations. What happened to the egg and corn syrup?

e.  What did you observe about the volume and appearance of the egg and the water (include your data)? Explain your observations. What happened?

3.  INTERPRETATION QUESTIONS: Answer with complete sentences.

The egg and solutions you used in the lab are a model system to help you describe what happens in other real-life situations involving cells and the movement of water into or out of the cells. Use what you learned in the lab to answer the following questions.

Situation / Is water concentration higher inside or outside cells? / Will water move into or out of cells? why?.
Fresh fruits and vegetables are sprinkled with water at a supermarket
Dried fruits and dried beans swell when they are soaked in water
Roads salt harms plants along the roadside
Lawn fertilizer (combination of various salts) accumulates in the soil. In dry weather, the grass often dies even if there is enough water.

4. DIAGRAMS

Solution / Isotonic,hypotonic hypertonic compared to egg? / Water moves into egg or out of egg? / Diagram showing movement of H2O
Vinegar
Corn syrup
Water

Define isotonic: ______

Define hypotonic: ______

Define hypertonic: ______

Draw a diagram of the egg membrane to show the movement of water into or out of the egg. Include

water and solute particles to show WHY water moved into or out of egg.