Mystery Worms

1. Mystery Worms 1. Formulate a hypothesis that might explain the presence of the �worms� in the container. 2. How could you test your hypothesis? 3. Identify the variables in your proposed experiment. Identify the control in your proposed experiment.

2. Section 2 Answers 1. Formulate a hypothesis that might explain the presence of the �worms� in the container.  2. How could you test your hypothesis?  3. Identify the variables in your proposed experiment. Identify the control in your proposed experiment.

3. 1�2 How Scientists Work A. Designing an Experiment 1. Asking a Question a. How do new living things, or organisms, come into being?

4. 2. Forming a Hypothesis a. Spontaneous generation-life arising from nonliving matter. b. 1668 Francesco Redi proposed a different hypothesis for the arrival of maggots on meat than spontaneous generation.

6. 3. Setting Up a Controlled Experiment a. Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled.(controlled experiment) b. The variable that is deliberately changed is called the manipulated variable. c. The variable that is observed is called the responding variable.

7. 4. Recording and Analyzing Results a. Detailed data should be kept during and experiment. b. Examples of data: time, temperature, number of tries, number of maggots, weight of meat throughout the experiment, etc.)

8. 5. Drawing a Conclusion a. Scientists use the data from an experiment to evaluate the hypothesis and draw a valid conclusion. b. In a valid conclusion you might prove or disprove your hypothesis. Both are valid answers.

9. B. Publishing and Repeating Investigations- a key assumption in science is that experimental results can be reproduced because nature behaves in a consistent manner.

10. 1. Needham�s Test of Redi�s Findings a. Mid 1700�s John Needham, and English scientist. b. Boiled gravy and things still grew in them. This disproved Redi�s findings. But the flasks were open to the air.

11. 2. Spallanzani�s Test of Redi�s Findings a. Lazzaro Spallanzani and Italian scholar read Needham�s and Redi�s work and tested both. b. Did the same thing but right after boiling he sealed one of the containers. The unsealed one grew bacteria the other did not. What does this prove?

13. 3. Pasteur�s Test of Spontaneous Generation a. Well into the 1800�s Louis Pasteur found a way to settle the argument. In 1864 he did another experiment on spontaneous generation. b. He boiled broth in several flasks with curved necks (page 12). This let in air. None grew bacteria. c. He broke off some of the curved necks and in a couple days they grew bacteria.

18. 4. The Impact of Pasteur�s Work a. Developed the first vaccine against anthrax, pasteurization. His research had an impact on society as well as on scientific thought.

19. C. When Experiments Are Not Possible 1. Some science experiment cannot occur in the laboratory. These are called field studies. For example it is only in the wild that you can see true way and animal acts.

20. D. How a Theory Develops 1. When a hypothesis has become so well supported scientist will consider it a theory. 2. In science, the word theory applies to a well-tested explanation that unifies a broad range of observations. 3. A theory can become the dominant view among the majority of scientist, but no theory is considered absolute truth.