Name___________________________________________________ Period___________ Date____________
Simpson Science!
Read the following scenarios and write a hypothesis for each.
Remember to write it in the correct form. Your hypothesis should
include what is being tested and what is being measured. Also list
the independent variable, dependent variable, and controlled
variables.
Experiment #1
Marge Simpson decided to start a new garden in her backyard. She heard that plants compete
for space and decided to test this idea. She bought a mixture of flower seeds and some
potting soil. She put the same amount of soil into each of 5 plastic cups. In the first cup she
planted 2 seeds, in the second cup she planted 4 seeds, in the third cup 8 seeds, and in the
fourth cup she planted 16 seeds. In the last cup she planted 32 seeds. After 25 days, she
determined which set of plants looked the healthiest.
Independent variable (IV): (The thing that is changed):_______________________________
Dependent variable (DV): (The thing that will be measured):_____________________________
Controlled variables: (The things that will be kept the same):______________________________
Hypothesis (IF…..THEN….BECAUSE):
Experiment #2
Homer was told that a certain itching powder was the newest best thing on the market. It
even claims to decrease itching by 50 % because it contains caffeine. Interested in this
product, he buys the itching powder and compares it to his usual product, which contains aloe
vera. On one itching spot, he puts the new powder. On another itching spot, he puts his old
cream. He then times how long it takes for the products to stop his itch.
Independent variable (IV): ___________________________________________
Dependent variable (DV): ____________________________________________
Controlled variables: ________________________________________________
Hypothesis (IF…..THEN….BECAUSE):
Experiment #3
Bart believes that mice who eat cat food will live longer lives. He decides to
perform this experiment by feeding 10 mice cat food, and 10 mice a regular
diet of cheese and bread crumbs. He then keeps the mice in his bedroom for
many years to see which group lives the longest.
Independent variable (IV): ____________________________________
Dependent variable (DV): _____________________________________
Controlled variables: _________________________________________
Hypothesis (IF…..THEN….BECAUSE):
Experiment #4
Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which
is a commercial hair product) affect the speed of hair growth". Her family is willing to
volunteer for the experiment. Describe how Lisa would perform this experiment. Identify the
independent and dependent variables in your description.
Description:
Independent variable (IV): ________________________________________
Dependent variable (DV): _________________________________________
Controlled variables: _____________________________________________
Hypothesis (IF…..THEN….BECAUSE):
Directions: Read experimental design 1 and 2 stated below. Identify the type of experiment,
component parts, and one possible hypothesis for each design. A complete sentences is
necessary for your hypothesis.
1. An experiment is conducted to determine the effects of energy drinks on an individual’s heart rate.
Groups A and B have been matched for all factors such as age and sex. Each person in group A is given
two ‘Red Bull’ energy drinks for breakfast and lunch, and then the heart rate is measured. Each person
in group B is given water to drink with breakfast and lunch, and then their heart rate is measured. Both
groups are fed the same breakfast and lunch. The results are recorded.
What is this experiment testing?
Independent Variable?
Dependent Variable?
What is one possible hypothesis for this design?
2. An experiment is conducted to determine the effect of classical music on the growth rate of marigolds
(flowers). Two groups of plants are grown from seed in identical soil types, exposed to identical light
conditions, and given the same nutrients. Group A is in a quiet atmosphere. The plants in group B
provided with the same atmosphere, except that classical music is played for twelve hours daily in this
area. The scientist measures the plants in both groups each day and records the data.
What is this experiment testing?
Independent Variable?
Dependent Variable?
What is one possible hypothesis for this design?
3. Use the following hypothesis to design a controlled experiment. Identify the component parts.
Hypothesis: Infants exposed to cigarette smoke have higher carbon monoxide levels in their
bloodstreams than infants living in smoke-free environments.
What is this experiment testing?
Independent Variable?
Dependent Variable?
What is one possible hypothesis for this design?
VARIABLES
In a controlled experiment, only one variable is changed. This is called the independent variable. The variable
that changes in response to the independent variable is called the dependent variable. The variables that are
kept constant are called the controlled variables.
Identify the independent variable, dependent variable, and two of the controlled variables in the experiment
shown.
Types of Variables
Independent Variable
Dependent Variable
Controlled Variables
Use the diagram and table to answer the question.
1. Suppose the scientist had put one type of gravy in the
flask he left open and another in the flask he sealed. Would
this be a well-designed experiment?
Explain.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
SCIENTIFIC METHOD
Read the following description and identify the elements of the experiment.
Sam wished to investigate how fertilizer run-off affects the growth of algae in lakes. He set up his experiment
in this way—First, he found five beakers. To each beaker, he added 900 mL of water. In addition to each
beaker, he added 5 mL of water that contained a large amount of algae. The beakers were placed under a
grow light which was timed to provide 12 hours of light each day. Liquid fertilizer was added to the beakers in
the following amounts:
Beaker 1 – no fertilizer
Beaker 2 – 2 mL of fertilizer
Beaker 3 – 4 mL of fertilizer
Beaker 4 – 5 mL of fertilizer
Beaker 5 – 8 mL of fertilizer
Each week, a sample from each of the beakers was examined under a microscope to get a count of the
number of algae cells present. His final results showed that the average amount of algae found in each of the
five beakers was as follows:
Beaker 1 – 50 algae
Beaker 2 – 35 algae
Beaker 3 – 15 algae
Beaker 4 – 10 algae
Beaker 5 – 0 algae
1. State the problem/purpose that Sam in investigating.
2. Show Sam’s experiment by drawing a picture of the set-up.
3. What is the test variable in this experiment? ______________________________________
4. Which beaker(s) is/are part of the experimental group? ______________________________
5. Which beaker(s) is/are part of the control group?____________________________________
6. What variables did Sam control in his experiment? ___________________________________
______________________________________________________________________________
7. What is the independent variable? _______________________________________________
8. What is the dependent variable? _________________________________________________
9. In the space below, write a conclusion based on Sam’s data.
Tables and Graphs
10. Create a chart based on Sam’s data using the data table below:
11. Create a line graph using Sam’s data. Plot ‘Amount of Fertilizer’ on the X-axis and ‘Algae’ on the Y-axis.
For each of the scenarios below:
A. Identify:
1. Independent variable (the thing that the student is changing in the experiment)
2. Dependent variable (the thing that the student plans on measuring in the experiment)
3. Number of repeated trials (how many times did the student do the experiment?)
4. Constants (the things that stayed the same in each group in the experiment)
5. Control (the comparison group)
6. Experimental (the group(s) that gets the treatment change)
B. Identify the hypothesis (the idea being tested) for the experiment; if the hypothesis is not explicitly
stated then write a possible hypothesis for the scenario.
C. State at least two ways to improve the experiment described in the scenario.
Chloe wanted to find out if the color of a food would affect how quickly kindergarten children would eat it for
lunch. She believed that brightly colored food would be eaten more quickly because of the urgency of the color.
She put food coloring into 4 identical serving bowls filled with mashed potatoes. A 5 th identical bowl received
only plain natural mashed potatoes. The colors were natural white, red, blue, green, and yellow. Each child
was given a scoop of potatoes. Chloe did this experiment using 50 kindergarten students. 10 students were
given each of the colors. She recorded the start and finish time of each student eating the potatoes and then
calculated the difference in seconds. She did this over 5 days with each student getting each color. Multiple
data takers (Chloe’s friends) made this experiment possible.
A. Identify the following:
1. State the problem (question):
a) Independent variable:
b) Dependent variable:
2. Number of repeated trials:
3. Constants/Controls:
4. Control group:
5. Experimental group:
B. Hypothesis:
C. One way to improve this scenario:
Second way to improve:
Ten seeds were planted in five pots (two seeds per pot) that Erica found around the house. Each contained
exactly 500g of Peat’s Potting Soil. The pots were given the following amounts of purified water each day for
40 days. Pot 1: 50mL, Pot 2: 100mL, Pot 3: 150mL, Pot 4: 200mL, Pot 5: 250mL. Pot 3 received the
recommended amount of water. The dry mass of each pot with soil and plant was measured at the end of the
experiment after being placed in a drying oven for 4 days.
A. Identify the following:
1. State the problem (question):
a) Independent variable:
b) Dependent variable:
2. Number of repeated trials:
3. Constants/Controls:
4. Control group:
5. Experimental group:
B. Hypothesis:
C. One way to improve this scenario:
Second way to improve: