Next Step Inquiry Bonus Assignment

Begin by reading the student handout on my website under 3rd six weeks materials. You may print it, or you may save paper and write your answers on a sheet of paper. Be aware that this version is adapted slightly in that the salt solution is included in the collard green experiment instead of doing 2 different investigations. Problem: What happens to the turgor pressure and rigidity of a plant when the plant loses or gains water?

Hypothesis:

Materials:

 3 wilted collard green leaves, larger is better  Metric ruler  3 quarters  Tape  3 tall glasses that can hold water and the tall collard green leaves without falling  Watch, clock, or timer  3 grams (about ½ tsp) table salt  Measuring spoons and cups  Knife or kitchen scissors

Procedure:

1. Find the mass of the quarter (6 grams) 2. Turn the wilted collard green leaf so that the underside of the leaf is facing up and tape the quarter to the leaf about 5 cm from the tip of the leaf. Repeat for the second and third leaves. 3. Put 300 mL (about 8 oz) water in each glass. 4. Label one glass salt water, one tap water and one no water. 5. Add 3 grams (a little less than ½ tsp salt) to the salt water glass and stir until dissolved. 6. Cut about 1 cm off the very end of each leaf stem before placing each leaf into a separate cup. 7. Measure and record the height of the quarter from the top of the table. Sketch the experimental set up. 8. Repeat this measurement at one hour intervals, for at least 6 hours. 9. Sketch the final set up to show the end result of the leaves. 10. After the last measurement, calculate the work the leaf did lifting the quarter. Design: (Fill in the information below)

Independent Variable: Dependent Variable: Constants: Control:

Data and Observations: (Remember to write your titles and units)

No Water Tap Water Salt Water 1 2 3 4 5 6

Before: After:

Data Analysis:

1. Distance (in meters) = (Final Height – Initial Height)/100

______m = (______cm - ______cm)/100

2. Force (in Newton’s) = Mass (in grams) x Acceleration due to gravity /1000

______N = ______g x 9.8 m/s2 / 1000

3. Work = Force (in Newtons) x Distance ( in meters)

______J = ______N x ______m Analysis Questions:

1. What did I discover in this investigation?

2. What do my results mean?

3. What generalizations or predictions can be made based on my observations?

4. How do my results help answer my question of inquiry and add to my knowledge of the relationship between water content and turgor pressure?

Conclusion:

The hypothesis is ______. It stated “ ______. ” To test the hypothesis, three wilted collard green leaves were placed into three different containers. One leaf was left without water, one leaf was placed in a 10% salt water solution and one leaf was paced in plain tap water. Each leaf was placed in the cup with the underside up and a quarter was taped 5 cm from the tip of the leaf. The height from the quarter to the table top was measured and recorded initially, and at one hour intervals for ______hours. During the experiment it was observed that ______and ______. Therefore, if ______then ______.

Question for further study/application: You purchased celery for a dinner ingredient, but accidently left it out on the counter and it wilted. You can’t serve it to your guests in this condition and do not have time to go to the store. What could you do?