Cell Transport Hands-On Lab Report
________________________________________
Instructions: There are two options for completing the lab. You can either complete the lab at home over the course of three days or watch the teacher-led video and record your observations. Links to the hands-on lab and video observation lab are on the 02.03Early Cells assessment page.
Title:
Objective(s):
Hypothesis:
Variables:
Materials:
• Raw egg
• String or thread or yarn
• Ruler
• White vinegar
• Tap water
• Syrup
• Jar with lid (like a mayonnaise jar or something big enough to put the egg in)
Procedures:
1. Before beginning the experiment, record at least two observations of the raw egg in your lab report.
2. Wrap the string around the center of the egg to determine its initial circumference. Measure the string and record the initial circumference in centimeters (cm).
3. Gently place the egg in the jar and completely cover the egg with vinegar. Use the lid to seal the jar and note the time. This will be considered the “start time” of the experiment.
4. After approximately 24 hours from the start time, carefully remove the egg from the jar of vinegar. If the shell has completely dissolved, exposing the inner membrane, move on to the next step. If not, return the egg to the vinegar until the shell has completely dissolved.
5. Record at least two observations of the egg.
6. Measure and record the circumference of the egg, being sure to measure it in the same way every time you measure circumference.
7. Pour out the vinegar and rinse the jar. Then fill the jar about half full of tap water.
8. Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
9. After a total of 48 hours from the start time, carefully remove the egg from the jar of water.
10. Make two observations of the raw egg, and measure and record the circumference.
11. Gently place the egg back into the jar, making sure it is completely covered with water. Use the lid to seal the jar.
12. After a total of 72 hours from the start time, carefully remove the egg from the jar of water.
13. Make two observations of the raw egg, and measure and record the circumference.
14. Complete the data and conclusion sections of the lab. Then complete the “refining the experiment” section.
Data and Observations:
Record your observations from the experiment in either the hands-on lab or the teacher led video. Don’t forget to include at least two detailed observations and the measurement of the egg’s circumference in centimeters.
Time (hrs) Observations Circumference (cm)
0 1. 2.
24 1. 2.
48 1. 2.
72 1. 2.
Conclusion:
Be sure to address each bullet in the conclusion of your lab report. The conclusion should be written in paragraph format:
• Was your hypothesis correct? Why or why not?
• How much did the egg change in size? (answer should be in centimeters)
• Evaluate the lab and data collected. Describe the accuracy and precision of your data collection.
• Describe the limitations (e.g., cost or time of measurement) that may have caused inaccuracies. How would you refine your procedures to increase the precision and accuracy of your data?
• What type of transport occurred in this lab? Explain your answer, including evidence from your experiment to support your explanation.
Refining the Experiment:
Continue this experiment by removing the egg from the water and covering it in syrup. Be sure to allow at least 24 hours before making your observations. Handle the egg very carefully!
• Predict what will happen to the egg and syrup system.
When refining your procedures describe the following:
• How will the change in the syrup and within the egg be measured or identified?
• How will you determine when homeostasis has been reached in your egg and syrup system?
Be sure to address each bullet in the conclusion of your lab report:
• Was your hypothesis correct? Why or why not?
• How much did the egg change in size? (answer should be in centimeters)
Text Version for Cellular Transportation Lab: 5.10 minutes
________________________________________
“Welcome to the Cellular Transportation Lab. Please make you have opened and read all of the instructions on the lab report before beginning. If you need time to do this, please pause the presentation.”
Short pause
“In this lab, you will see the transportation of water through a cell. We call this osmosis. An egg is a great example of a cell. Underneath the hard shell is a thin membrane that is just like the cell membrane of your cells. There are microscopic pores in the membrane that allow substances to move in and out of the cell. If you remember, the cell membrane controls materials in and out of cells. This maintains homeostasis, which is the balance between conditions inside and outside the cell. We’ll measure how cells are affected by the movement of water.”
Short pause
“In this lab, the materials that were used were a raw egg, yarn, a metric ruler, white vinegar, tap water, and a jar with a lid.”
Short pause
“The summary of the procedures are as follows: The egg was placed in vinegar, where it dissolved the shell within the first 24 hours. The egg was then placed in water for two days, or 48 hours. Each day, two observations and the circumference of the egg was taken at four different points. It was taken at the zero point, the 24-hour mark, the 48-hour mark, and the 72-hour mark after starting the experiment. Each day, the yarn and the ruler were used to measure the circumference of the egg in centimeters.”
Short pause
“Okay let’s pause for a moment. Have you recorded your hypothesis on your lab report yet? What do you anticipate will happen to the size of the egg as you observe osmosis through the cell membrane? If you have not recorded your hypothesis yet, please pause the presentation. Record your hypothesis, review your procedures, and get ready to start recording your data.”
Short pause
“Let’s continue with the experiment. Here is a picture of the egg on the first day at the zero-hour mark. You can see that yarn was used to measure the circumference of the hard outer shell. Take a moment to pause the presentation, and on your data table record two visual observations along with your data that was collected on the circumference of the yarn. You can use the ruler provided to measure this distance.”
Short pause
“Continuing on with the experiment and fast forwarding through time. You can see in the second picture the egg has now sat in vinegar for 24 hours. The shell is dissolved, and new circumference measurements were taken.”
“What do you anticipate the egg would feel like with no shell?”
“What do you think would happen to the size of the egg after 24 hours?”
“You can notice the visual differences in the appearance of the egg. Pause the presentation, record two observations using the picture, and again in your data table, record the distance of the circumference using the ruler provided.”
Short pause
“We are currently at the 48-hour mark with our lab experiment. At 48 hours, the egg has now been soaking in a jar of water for 24 hours.”
“What do you anticipate the egg would feel like at this point? What visual observations can you make of the egg in the jar?”
“At 48 hours, the circumference of the egg was taken. You can see on the presentation the length of the yarn. Use the ruler provided to collect your data. Pause the presentation and record two observations of your data on your data table.”
Short pause
“We are now at the 72-hour mark. The egg has been soaking in water for the last two days. The membrane is starting to look transparent.”
“What other observations can you make about the egg?”
“At 72 hours the circumference of the egg was taken. The length of the yarn and a ruler are provided for you to record your data. Take a minute and record two observations of your data in your data table.”
Short pause
“At this point you should have completed your lab report. Make sure that you have completed your hypothesis, that you have a data table that includes all of the measurements and observations and answered your conclusion questions. I hope this lab activity was an experience you enjoyed.”