Question

ada and elijah have decided to do an experiment testing how sunlight affects plant growth. the students choose the same type of plants, soil, pots and amount of water they give the plants. they also make sure each plant is put in their designated area for the same amount of time each day. one plant is placed outside; one in front of a window that only gets light for 1/2 the day, and one in a closet. the students collect data every day for two weeks. their results show that the plant outside grew the most and the plant in the closet had the least amount of growth. what are the constant variables that ada and elijah used in their experiment?
a. type of environment
b. type of soil
c. amount of light
d. a and b

a scientific hypothesis *
a. can be based on personal beliefs or opinions
b. can be tested by experiments or observations
c. does not have to be tested to be accepted as correct
d. is a proven fact with much evidence to support it

Explanation:

For the first question, constant variables are factors that are kept the same throughout an experiment. Ada and Elijah kept the type of plant, soil, pots, amount of water, and time - in - place the same. Type of soil is a constant variable. The type of environment is different (outside, window, closet) and amount of light is the independent variable being tested.
For the second question, a scientific hypothesis is a proposed explanation made on the basis of limited evidence as a starting point for further investigation. It can be tested by experiments or observations. It is not based on personal beliefs, must be tested to be accepted, and is not a proven fact.

Answer:

1. B. type of soil
2. b. Can be tested by experiments or observations