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 Toxicology Experiment and Lab report assignment

 Toxicology Experiment and Lab report assignment


Project deliverables:

At the end of this project you will need to upload a copy of your lab assignment and report (see guidelines below). You will upload your assignment into your Canvas course under the “Toxicology experiment and lab report” module.


You are trying to determine the effect of salt toxicity on the sprouting of beans for the Office of Pesticide Programs (OPP) at the Environmental Protection Agency (EPA). We are interested in determining the toxicity of salt (between 0-1%) on beans. In other words, we want to know how high a concentration of salt we can use without significantly impacting the germination rate of beans.


Experimental Design

Formally, in order to apply the scientific method we need to:

  • State the problem
  • Develop hypotheses
  • Design and Perform Experiment
  • Analyze and interpret the results
  • Share the conclusions with others


First, read the scientific method background document in your Toxicology lab module and answer questions 1-7 below.


State the problem: We must always have a specific thing that we are trying to measure and a way to measure that hypothesis.


  1. What specifically are we trying to find out with this experiment?





Develop hypotheses: We HAVE to have a very clear statement of what we think the relationship between our dependent and independent variables will be. To do this we write hypotheses. Hypotheses should be very clear and MUST ALWAYS BE TESTABLE!


  1. What is the independent variable in this experiment?




  1. What is the dependent variable in this experiment?


  1. Briefly describe the difference between an alternative hypothesis (HA) and a null hypothesis (H0). What does each say about the relationship between our measured effect (dependent variable) and our assumed cause (independent variable)?








State the two hypotheses (null and alternative) for our salt/bean germination experiment below:



  1. H0:






  1. HA:



  1. What endpoint are we going to measure to determine any effects? In other words, what will be looking at in order to determine if our independent variable is affecting our dependent variable?




Note: These instructions below are just for your information, we are not requiring you to perform the experiment but you need to know how it was done in order to write a report about it (methodology).


Design and perform experiment (methods): First you will design the experiment to test for effects of salt concentration on bean germination. These beans usually have a 5-7 day germination window, so the first week you will design and set up your experiment and next week you can look at your beans to evaluate their actual germination rate. For this lab, you will test 3 different salt concentrations between 0-1% (plus your control-0%).


  1. Make the saltwater solutions

For this experiment, you will first need to make up the saltwater solutions you will use on your beans. You will be making 3 different solutions. Your fourth solution will just be plain water (the control group). The 3 solutions you will make will be a 1% salt solution, a 0.50% salt solution and a 0.25% salt solution.


In order to make the first solution, you will need to dissolve 2 teaspoons of table salt into 1000 mL (or 1 Liter) of water. This is your 1% salt solution. Put 1 cup of this solution

aside to use later.


Take another cup of your 1% salt solution and mix it with 1 cup of plain water. You have now diluted it down to a 0.50% salt solution. Put this aside for later use.


Take 1 cup of the 0.50% solution you just made and mix that with 1 cup of water. You have now diluted that down to a 0.25% salt solution.


  1. Take 4 Ziploc bags and label them with the test groups (0%, 1%, 0.50% and 0.25%)


  1. Dampen a paper towel into each of the salt solutions and place the paper towel into the appropriate Ziploc bag. For example, place 1 paper towel into the 1% salt solution, squeeze it out a little bit so it is damp (not dripping wet), and then fold the paper towel and put it into the Ziploc bag labeled 1%. Repeat with each of the different salt concentrations.


  1. In each Ziploc bag, place 10 beans onto the paper towel. Space out the beans inside the paper towel so that they are not crowded.


  1. Lay the Ziploc bag flat and leave undisturbed for 5-7 days. It should be in a spot that is not too hot or cold. After 5-7 days, examine the beans to see if they have germinated. A germinated bean will have sprouted from the seed and begun to grow.


Results- Since you did not have to actually conduct this experiment, we are also giving you a set of results. You will use these in your lab report (results and discussion).


Table 1: Number of Beans Germinating in Salt water Exposed (x% salt) and Control Groups by Replication and Total Number. Each group used 10 beans in each treatment.


Lab Group # of Beans Germinated in Control Group (0%) # of Beans Germinated in Experimental Group (.25%) # of Beans Germinated in Experimental Group (.50%) # of Beans Germinated in Experimental Group (1.0%)
Group 1


10 9 5 0



Analyze and interpret results: This is where you write a lab report about the experiment/


Lab report guidelines

Your lab report should be written in 12 point font, double spaced. The report should be written using full sentences and paragraphs, not bulleted lists of information. It should be approximately 2-4 pages in length including the dose-response graph in the results section. You should write (or insert) your lab report below under the heading “Lab report” located just after the guidelines below.

Your lab report should have all of the following sections. Please include all of the information outlined in each section. You also need to include a section heading in bold for each section in your lab report (Intro, Methods, Results and Discussion)


The introduction establishes the purpose of the report. A  well  written introduction should answer  the  questions, why  are  we  doing  this  research  and what  do we  hope  to find out?  You also need to include your hypotheses in this section.


The methods section should be a straightforward description of what you did in your experiment. This includes describing the materials you used and how you used them. Based on your methodology section, the reader should be able to replicate your experiment.


The results are a summary of your observations.  You need to report on all of your results, do not leave anything out. Include a data table reporting on your results. Avoid discussing what your results may mean in this section. That information belongs in the discussion/conclusions section.

Discussion and Conclusions

Based on your results, did your outcomes support your original hypothesis?  Keep in mind  that  science never truly  proves  anything;  it  contributes  to a  growing  body  of  evidence  about  the  way  our  world works.  If your research does not appear to support your hypothesis, be truthful about that. Remember  that  in science  we  learn as  much from  failures  as  we do  from  successes.


Lab Report

Insert/ write your lab report here. Make sure you have every section as outlined above:



Assignment submission:

  1. Your lab report should be written as part of this lab exercise (write it in the section above) and uploaded as either a Word document or pdf file. Look in the Canvas module titled “Toxicology experiment and lab report”. The lab report section of this assignment should be 2-4 pages in length, typed, using the section format outlined under the lab report guidelines above (make sure you have every section, with section headers and all of the required information listed in each section).