| Clouds are more beautiful on winter days than on summer days. |
This statement is a poor hypothesis because it is not —
A. a question
Incorrect. A question would be formed during the observation phase.
B. testable
Correct! A hypothesis is a tentative statement that proposes a possible explanation to some phenomenon or event. This statement would explain how two variables are related.
C. observable
Incorrect. A hypothesis is formed after observations are made.
D. a comparison
Incorrect. A hypothesis does not have to be a comparison.
A. testable
Incorrect. This is a characteristic, but are there others on the list?
B. possible answer to a scientific question
Incorrect. This is a characteristic, but are there others on the list?
C. follows from observations and research
Incorrect. This is a characteristic, but are there others on the list?
D. all of the above
Correct! These are all characteristics of a hypothesis.
Read the following lab scenario.
| Jackie read that Aloe vera promoted healing of burned tissue. She decided to investigate the effect of varying amounts of Aloe vera on the regeneration of planaria. She bisected (cut in ½) the planaria to obtain 10 parts (5 heads and 5 tails) for each experimental group. She applied 15 ml of the following Aloe vera solutions: Group A = 0% concentration; Group B = 10% concentration; Group C = 20% concentration; Group D = 30% concentration. All planaria were maintained in a growth chamber with identical food, temperature, and humidity. On day 15, Jackie observed the regeneration of the planaria parts and categorized development as full, partial, or none. |
Which of the following statements would be the best hypothesis for Jackie’s experiment?
A. As the temperature of the growth chamber increases, the regeneration of the planaria will also increase.
Incorrect. The temperature of the growth chamber is a constant. What is the independent variable in the experiment?
B. If the amount of food given to planaria is increased, then the regeneration of the planaria will increase.
Incorrect. The amount of food given is a constant. What is the independent variable in the experiment?
C. As the concentration of Aloe vera increases, then the regeneration rate of the planaria will also increase.
Correct! The concentration of Aloe vera is the independent variable and the regeneration rate of the planaria is the dependent variable.
D. If the concentration of the Aloe vera given to planaria is increased, then the reproductive rate of the planaria will decrease.
Incorrect. The reproductive rate of the planaria is not being tested. What is the dependent variable?
Read the following lab scenario.
| Ester became interested in insulation while her parent’s new house was being built. She decided to determine which insulation (brand A, brand B, or brand C) transferred the least heat. She filled 3 jars half-full with water. She sealed each jar with a plastic lid. Then she wrapped each jar with a different brand of insulation. She put the jars outside in direct sunlight. After 12 hours, she measured the temperature of the water in each jar. |
Which of the following statements would be the best hypothesis for Ester’s experiment?
A. If three brands of insulation (brand A, brand B, or brand C) are placed in sunlight for 12 hours, then brand C will transfer the least heat.
Correct! The brand of insulation is the independent variable and the amount of heat transferred is the independent variable.
B. If the amount of insulation is increased, then the jar with the most insulation will transfer the least heat.
Incorrect. The amount of insulation is constant. What is the independent variable?
C. If the amount of insulation is increased, then the temperature of the water will increase.
Incorrect. The amount of insulation is constant. What is the independent variable?
D. If the temperature of the water is increased, then the jar with the most insulation will transfer the least heat.
Incorrect. The temperature of the water is how Ester is determining the amount of heat that is transferred. What is the independent variable?