Apply Scientific Method to Interpret a Investigation

hypothesis

An informed guess about a causal relationship that is generated by observation and initial data collection

Scientific Method Steps 1

problem

2

question

3

hypothesis

4

experiment

5

analyze

6

conclusion

scientific hypothesis

A prediction of what will occur in an experiment based on previous research

Scientists are investigating the effect of water on germinating seeds. Their hypothesis is that water is necessary for seed germination. They have 100 seeds. Fifty seeds receive 25 mL of water each day, and 50 seeds receive no water. All other conditions such as amount of sunlight, temperature, soil conditions, and plant type are kept the same for every seed in the experiment. It is important to review the methodology of any investigation to determine if it is valid. This experiment only manipulates the water added to the seeds.

What is the independent

What is the dependent

What is the sample size

water, seed germinate, 50 seeds (gives more data to analyze)

variables

parts of the experiment that could be changed or manipulated during the experiment

What are the three types of variables

independent, dependent and control

independent variable example

type or concentration of a medicine, x on graph

water

dependent variable exapmple

what is measured after the independent variable is changed

growth or response

y axis

observing the germination of seeds

controlled variable

temperature and humidty

amount of sunlight

temp

soil conditions

type of plant

Based on previous research, a group of scientists believe that fruit flies are attracted to rotting fruit. They design an experiment to test this hypothesis. The scientists place 20 fruit flies in a chamber. On one side of the chamber, they place an unripe banana. On the other side of the chamber, they place a rotten banana. After 5 minutes, they count how many fruit flies are on each side of the chamber.

Which of the following is the dependent variable in the experiment?​​​​​​​

number of fruit flies on each side of the chamber because it is the data we are collecting with the response

Which of the following statements is the hypothesis in the experiment?​​​​​​​

If presented with a rotten banana, fruit flies will be attracted to it.

Juan Carlos hypothesizes that changing the color of light given to plants will affect their growth. He decides to test his prediction in an experiment. He sets up four groups of plants, giving each a different color of light. Each group has 10 radish plants all about 10 cm tall. He keeps all of them in the same temperature and gives them with the same amount of water each day. After 10 days, he records these results:

Light	Average Starting Height (cm)	Average Height after 10 days (cm)
Blue	10	17
Red	10	16
Green	10	11
Yellow	10	12

Which of the following is the independent variable in this experiment?​​​​​​​

color of the light

Which of the following should be controlled in this experiment?​​​​​​​

soil conditions and amount of water, since it could affect the outcome so it needs to be controlled

Reread the experimental design regarding the effect of light color on plant growth. Which of the following is a hypothesis that would be supported by the data collected by Juan Carlos?​​​​​​​

if plants are grown in blue or red light, they will grow at faster rates than those grown in green or yellow light.