LD50 Lab : Collaborators: Maggie, logan, & amber
Introduction:
The purpose of this experiment is to measure the effect of salt (NaCl) that is applied to highways for the purpose of combining with natural processes to deice the roads. When all of the snow and ice eventually melts the water becomes concentrated with salt and is absorbed by plants on the sides of roads. In the LD 50 Lab we were able to exemplify this by varying concentrations of salt and water in petri dishes along with plant seeds; this tests the effect of the salt on the plants that inhabit the banks of our road ways.The LD-5o lab tests the effects of salt on the germination and growth of plants. By definition, LD-50 is the amount of a material given all at once, which causes death of 50% of a test population. To see these results a dose-response curve, which is a graphical representation of the relationships between the particular does of a stressor and the biological response. The purpose of this lab is to determine the LD-50 of salt for radish seeds and to determine how salt affects the initial growth of radish plants. The results will show us exactly what kind of harm we are doing to the plant life in areas where salt has to constantly be applied to the roadways.
Problem
What is the LD 50 of radish seeds when submerged in different levels of salt water?
Hypothesis
If we test the effect of salt on the germination of seeds with varying concentrations of salt and water then the petri dishes with less than 50% concentration of salt will have more than 50% of seed germinate; whereas petri dishes with more than 50% concentration of salt will have less than 50% of seeds germinate.
Parts of the Experiment
Control- Petri dish with 0% concentration of salt
Experimental- Petri dishes with more than 0% concentration of salt
Independent Variable- Percent concentration of chemical
Dependent Variable- Percent of seeds germinated
Controlled Variables- Location, amount of sunlight, total volume of liquid, number of seeds,
Materials
6 petri dishes Water
6 seeds Graduated Cylinder
12 napkins Concentrated Salt Water Solution
Method:
2. Label all six bags with your group number, the dish #, and a percent concentration of chemical:
a. Bag #1: 0%
b. Bag #2: 6.25%
c. Bag #3: 12.5%
d. Bag #4: 25%
e. Bag #5: 50%
f. Bag #6: 100%
3. Put two napkins together and place them in the bag
4. Pour the chemical solutions onto the napkins, making sure to match the numbers of concentration percentages of the dish.
5. Count out 10 seeds. Carefully place the seeds in the bag making sure that they are each visible
6. Repeat steps 3-5 for the other dishes.
7. Place the seed dishes in a stack, lying flat with the seeds up. Put the seeds in the spot designated by your teacher.
The purpose of this experiment is to measure the effect of salt (NaCl) that is applied to highways for the purpose of combining with natural processes to deice the roads. When all of the snow and ice eventually melts the water becomes concentrated with salt and is absorbed by plants on the sides of roads. In the LD 50 Lab we were able to exemplify this by varying concentrations of salt and water in petri dishes along with plant seeds; this tests the effect of the salt on the plants that inhabit the banks of our road ways.The LD-5o lab tests the effects of salt on the germination and growth of plants. By definition, LD-50 is the amount of a material given all at once, which causes death of 50% of a test population. To see these results a dose-response curve, which is a graphical representation of the relationships between the particular does of a stressor and the biological response. The purpose of this lab is to determine the LD-50 of salt for radish seeds and to determine how salt affects the initial growth of radish plants. The results will show us exactly what kind of harm we are doing to the plant life in areas where salt has to constantly be applied to the roadways.
Problem
What is the LD 50 of radish seeds when submerged in different levels of salt water?
Hypothesis
If we test the effect of salt on the germination of seeds with varying concentrations of salt and water then the petri dishes with less than 50% concentration of salt will have more than 50% of seed germinate; whereas petri dishes with more than 50% concentration of salt will have less than 50% of seeds germinate.
Parts of the Experiment
Control- Petri dish with 0% concentration of salt
Experimental- Petri dishes with more than 0% concentration of salt
Independent Variable- Percent concentration of chemical
Dependent Variable- Percent of seeds germinated
Controlled Variables- Location, amount of sunlight, total volume of liquid, number of seeds,
Materials
6 petri dishes Water
6 seeds Graduated Cylinder
12 napkins Concentrated Salt Water Solution
Method:
2. Label all six bags with your group number, the dish #, and a percent concentration of chemical:
a. Bag #1: 0%
b. Bag #2: 6.25%
c. Bag #3: 12.5%
d. Bag #4: 25%
e. Bag #5: 50%
f. Bag #6: 100%
3. Put two napkins together and place them in the bag
4. Pour the chemical solutions onto the napkins, making sure to match the numbers of concentration percentages of the dish.
5. Count out 10 seeds. Carefully place the seeds in the bag making sure that they are each visible
6. Repeat steps 3-5 for the other dishes.
7. Place the seed dishes in a stack, lying flat with the seeds up. Put the seeds in the spot designated by your teacher.