What are the two basic conditions in experimental research?
Experimental research involves the differentiation of two basic conditions: exposure and non-exposure to the treatment condition of the independent variable. The experimental group is the group exposed to the treatment condition, while the control group is not subjected to treatment.
Is it possible to assess the differences between treatments?
Early on we learned that it is not possible to assess these differences based on a single measurement of each treatment. Without knowing how much variation existed within a treatment, we could not know if the difference between treatments was significantly large.
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Does random assignment of participants to a treatment condition increase validity?
Although random assignment of participants (or other units) to treatment condition can greatly enhance the likelihood of internal validity, problems can still occur. Most widely recognized is that differential attrition may occur, with more (or different kinds of) participants dropping out of one group than another.
How are the colonies from the two treatment conditions different?
The difference was that the heat killed some of the bacteria. How are the colonies from the two treatment conditions different (e.g., size, color, shape, etc.)? The normal colonies were small, yellow, off white, and red. They were shaped like irregular circles.
Which of the two hand treatments grew the most colonies?
2. Which of the two hand treatments grew the most colonies? Plate #1 was the hand without washing, and it grew the most colonies.
What conditions are most favorable for mold growth on bread and apples?
The conditions most favorable for mold growth on bread and apples are, temperature, pH, nutrients, water activity, and aeration. Temperature; since most mold are mesophillic, meaning, they can grow at a temperature range of 10-35 degrees celsius.
What purpose did the yeast plate serve in this experiment?
What purpose did plating the yeast serve in this experiment? The yeast serves as a positive control. It shows that the agar can support life and provides a visual of what microorganisms growing on agar can look like.
Which of the following hand washing conditions was most effective at lowering Species richness?
Handwashing with soap was more effective in reducing the prevalence of contamination and specifically of Enterococcus spp. There was a trend that handwashing with soap was also more effective in reducing the prevalence of other species and of multiple isolates, but the statistical support was low (Figure 1).
Which petri dish condition grew the most colonies?
The Petri dish with yeast and no hand washing grew the largest of the colonies.
What are the best conditions for the growth of bread mould Why?
Molds grow best in warm, dark and moist conditions. In the first sample, the sealed bread should develop mold more slowly than the unsealed bread. In the second sample, the bread kept in darkness should develop mold more quickly than the bread kept in light.
What are the conditions favorable for growth of molds?
Water: Molds thrive in damp, humid, and wet conditions. They require water to grow and spread, which is why it is recommended to keep homes – especially walls and carpets – as dry as possible. Water leaks, flooding, high humidity, and condensation all provide moisture mold can use to grow and spread.
What conditions are needed for bread mould to grow?
As bread mold is a living organism, it requires moisture and oxygen to grow. The moisture trapped in the bag is absorbed by the fungus and it grows at a faster rate. However, as mold is a type of fungi and not a plant, bread mold does not require light for its growth.
Under what conditions are media typically sterilized in an autoclave?
Under what conditions are media typically sterilized in an autoclave? Media are sterilized at 121ºC with 15 psi of steam for at least 15 minutes.
What is the difference between a disinfectant and an antiseptic quizlet?
An antiseptic is used to remove or kill microorganisms on tissue, whereas a disinfectant is used to remove or kill microorganisms on inanimate objects.
Why do we use positive and negative controls in the Gram stain quizlet?
The positive and negative controls are bacterial smears we use to test if the Gram stain was performed properly. If the positive and negative controls are not as expected, you can not trust that the stain was performed properly. As a Positive Control we use a known Gram-positive bacteria.