LD-50 Lab
Problem
Is salt harmful to the growth of vegetation along side the road?
Hypothesis
If more NaCl is applied to the seeds then they will germinate slowly and their radical lengths will be shorter or they will not germinate at all.
Parts of the Experiment
Independent Variable: various concentrations used
Dependent Variable: seeds germinating and their length
Controlled Variables: type of seeds, volume of liquid, number of seeds used in each petri dish
Control Group: seeds with no concentration
Experimental Group: seeds with concentration
Dependent Variable: seeds germinating and their length
Controlled Variables: type of seeds, volume of liquid, number of seeds used in each petri dish
Control Group: seeds with no concentration
Experimental Group: seeds with concentration
Materials
6 petri dishes
6 napkins
60 seeds
Concentrated salt water solution
Water
Graduated cylinder
Breaker
6 napkins
60 seeds
Concentrated salt water solution
Water
Graduated cylinder
Breaker
Procedure
1) Label the petri dishes with numbers 1-6 and their percent of concentration.
2) Count out 10 seeds for each petri dish and place them into a napkin inside each dish.
3) Add the various concentrations and water to each petri dish as directed by the table given.
4) Place petri dishes in a safe location where they will not be touched and let them sit there for about 3-4 days.
5) Take out seeds from each petri dish and measure the length of their radicals, then record the data.
2) Count out 10 seeds for each petri dish and place them into a napkin inside each dish.
3) Add the various concentrations and water to each petri dish as directed by the table given.
4) Place petri dishes in a safe location where they will not be touched and let them sit there for about 3-4 days.
5) Take out seeds from each petri dish and measure the length of their radicals, then record the data.
Observations
Groups 1 and 2 had the highest percentage of germinated seeds, but also had the smallest radical lengths. Groups 3, 4, and 5 had the lowest percentage of seeds germinated but had larger radical lengths. Group 6 did not germinate at all.
Data Table and Graphs
seed_table.docx | |
File Size: | 41 kb |
File Type: | docx |
Analysis and Conclusions Specific to the Lab
1) The LD-50 for the radish seeds was 12.5% concentration because when this amount of concentration was added to the seeds, 50% of the seeds did not germinate.
2) The radical data is not supported by the germination data because even though the LD-50 was 12.5%, it was also the amount of concentration where the seeds had the longest radical lengths. As for the lower concentrations, they all had shorter radical lengths.
2) The radical data is not supported by the germination data because even though the LD-50 was 12.5%, it was also the amount of concentration where the seeds had the longest radical lengths. As for the lower concentrations, they all had shorter radical lengths.
General Analysis and Conclusions
The lab was alright but the radical and germination data did not support each other because the seeds grew longer radical lengths at their LD-50, which was 12.5% than at lower concentrations. When I compared our data with the rest of the class, I saw that many people's results turned out like ours. The data did not support all of my hypothesis because the radical length did not get shorter as the salt concentration increased, but they did stop germinating as it increased. Along with the LD-50 test being used to test chemicals' effect on vegetation, it is also used to test cosmetic products. Many companies use LD-50 testing on animals to see the effects of their products. Often, the animals die or have damage to their organs from the products, but now many countries are creating laws to ban animal testing and many consumers are pushing for these laws to be passed.
Hoffman, Piper. "Testing Cosmetics on Animals is Going Out of Style." Care 2 Make a Difference. Care2.com, Inc, 19 Mar. 2013. Web. 26 Mar. 2013. <http://www.care2.com/causes/testing-cosmetics-on-animals-is-going-out-of-style.html>.
Hoffman, Piper. "Testing Cosmetics on Animals is Going Out of Style." Care 2 Make a Difference. Care2.com, Inc, 19 Mar. 2013. Web. 26 Mar. 2013. <http://www.care2.com/causes/testing-cosmetics-on-animals-is-going-out-of-style.html>.