Lab - Introduction to Science
Exercise : The Scientific Method
In this exercise, you will answer the questions based on what you have seen in the videos throughout the lab. Be sure to pay careful attention to the videos - you will not only need them to complete this exercisesuccessfully, but also to have a firm understanding of the scientific method for future labs.
QUESTIONS
1. Make an observation - Write down any observations you have made regarding the effect of pollution on the environment.
2. Do background research - Utilizing the scholarly source (provided here), describe how pollution might affect yeast.
3. Construct a hypothesis - Based on your research from question 2, develop an if-then hypothesis relating to the effect of pollution on yeast respiration.
4. Test with an experiment - Identify the dependent variable, independent variable, and the controlled variables for the experiment.
5. Analyze results-Record your observations of the three test tubes before incubation and compare them to the observations provided in the video.
Test Tube Initial Appearance
Yeast with No Pollutant
Yeast with Salt Water
Yeast with Detergent
6. Analyze results-Record your observations of the three test tubes after incubation.
Test Tube Final Appearance
Yeast with No Pollutant
Yeast with Salt Water
Yeast with Detergent
7. Analyze results-The table below shows sample data regarding the amount of carbon dioxide produced by each tube. Determine what type of graph would be the most appropriate for displaying the data and explain why you chose that graph. Then, make a graph. Use Microsoft Excel or a free graphing program (for example, https://nces.ed.gov/nceskids/createagraph/) to create the graph. Submit this with your post-lab questions.
Sample Amount CO2 Produced (mL) After 1 Hour
Yeast with No Pollutant 7 mL
Yeast with Salt Water 0.5 mL
Yeast with Detergent 0 mL
8. Draw conclusions - Interpret the data from the graph in Question 7. What conclusions can you make based on this graph?
9. Draw conclusions - Based on your observations and your graph, would you reject or accept the hypothesis you made in Question 3? Why?
10. Draw conclusions - Imagine you are an environmental scientist employed by a city. Some residents have expressed concerns regarding how salt is applied to roadways in the winter because of the harm it may cause aquatic life in area streams. Propose an experiment using yeast to determine if salt pollution runoff is a potential concern in your community.