Question

situations: read the situation below and design an experiment.
a: john smith has been hired by the city of virginia beach to investigate the recent shark attacks off the resorts coast. he has a budget of $40,000, a 25 foot boat, and three graduate student assistants to help him. a helicopter has also been donated by a local television station, should he need one.

1. list 2 hypotheses john and his crew may have come up with for the recent shark attacks.

a. if______________________, then______________________
b. if______________________, then______________________

1. pick one of the two hypotheses and determine the following:

a. control group: time of year when elephant seals are not present or another area with no elephant seals
b. experimental group: times/areas when/where elephant seals vary
c. dependent variable:________________________
d. independent variable:________________________

1. what type of data do you think john will collect (what will be the results of the experiment)?
2. what conclusions will john be able to make from the results of the experiment?

b: suzie q wants to know the effect of different colors of light on the growth of plants. she believes that plants can survive best in white light. she buys 5 ferns of the same species, which are all approximately the same age and height. she places one in white light, one in blue light, one in green light, one in red light and one in the closet. all of the ferns are planted in miracle - grow and given 20 ml of water once a day for 2 weeks. after the two weeks, suzie observes the plants and makes measurements.
hypothesis: if plant growth is affected by color of light, then white light will produce the most plant growth.
independent variable:
dependent variable:
control group:
experimental group:
what could be the controlled variables?
what types of measurements can suzie make on the plants to determine how they did in different types of light?

Explanation:

• Independent Variable: The factor that is changed or manipulated in an experiment. In Suzie's experiment, it's the color of light as she is varying the light colors (white, blue, green, red) to see its effect.
• Dependent Variable: The factor that is measured and changes in response to the independent variable. Here, it's plant growth as she is observing how different light colors affect how much the plants grow.
• Control Group: A group that serves as a standard of comparison. The fern in the closet (no light - assuming normal room conditions but no experimental light exposure like the colored lights) is the control as it's not exposed to the experimental light colors.
• Experimental Group: The groups that receive the treatment (the different colored lights). So, the ferns under white, blue, green, and red light are the experimental groups.
• Controlled Variables: These are factors that are kept the same throughout the experiment to ensure that only the independent variable (light color) is affecting the dependent variable (plant growth). In this case, the species of fern (same species), age of fern (approximately the same age), height of fern (approximately the same height), type of soil (Miracle - Gro), amount of water (20 mL), and frequency of watering (once a day for 2 weeks) are controlled variables.
• Measurements for plant growth: She could measure the height of the ferns (using a ruler), the number of new leaves (counting), or the overall health (e.g., by rating on a scale based on leaf color, turgidity) of the ferns.

Answer:

• Independent Variable: Color of light
• Dependent Variable: Plant growth
• Control Group: Fern in the closet
• Experimental Group: Ferns under white, blue, green, and red light
• Controlled Variables: Species of fern, age of fern, height of fern, type of soil, amount of water, frequency of watering
• Measurements: Height of ferns, number of new leaves, overall health (e.g., leaf color, turgidity)