Scientific Method
Repetition/Replication
Scientific Explanation
Scientific Laws & Theories
Vocab
Lagniappe
100
In an experiment, 100 tomato plants were grown under blue wavelengths of light. An additional 100 tomato plants were grown under normal light conditions. What did the tomato plants grown under normal light conditions represent in the experiment?
Control Group
100
Mary gave her procedure to another student in the class and the other student performed the same experiment. What does this type of task represent in science?
replication
100
Scientists can use many strategies during investigations, including fieldwork, surveys, models, and experiments. True or False: An experiment can be described as a procedure with controlled conditions and test (independent) and outcome (dependent) variables.
True: procedure with controlled conditions and test (independent) and outcome (dependent) variables
100
The Big Bang theory is used to explain the origins of the universe. Why is this called a theory and NOT a law?
The Big Bang theory is a theory because it uses evidence to explain how the natural world works.
100
a group separated from the rest of the experiment, where the independent variable being tested cannot influence the results.
Control Group
100
When Alfred Wegener first published his theory of continental drift, the vast majority of scientists refused to accept the theory. It took 50 years before the theory of continental drift was accepted by the scientific community. What most likely caused geologists to accept Alfred Wegener’s theory?
Evidence supporting the theory slowly accumulated.
200
George investigates how far a rubber band stretches when he suspends an increasing amount of weight from it. He uses the same type of rubber band to test each amount of weight. The graph shows Stretch on the Y Axis and Weight on the X Axis. Based on this data, which variable is the outcome variable (dependent variable)? Hint: which variable is on the X axis and which variable is on the Y axis?
Stretch
200
Science is knowledge gained through repeated experiments or observations. To be convincing, a scientific paper needs to provide evidence that the results are reproducible. How is replication different from repeated trials?
Replication occurs when another scientist repeats an experiment. The same scientists conduct repeated trials.
200
Scientists pursue scientific explanations by using observations and inferences. Which of the following statements is an inference?
The plant’s leaves are green and appear wilted. An inference is what we learned in 6th grade
The plant uses water to perform photosynthesis. An inference is what happens in science.
The plant absorbs water through its root system. An inference is the same as an elephant.
The plant's leaves are wilted due to lack of water. An inference is an educated guess.
The plant's leaves are wilted due to lack of water. An inference is an educated guess.
200
A 6-mile wide meteorite hit the earth 65 million years ago. Scientists have found a high concentration of iridium in the sedimentary clay layer from this time period. Iridium is very rare in Earth’s crust, but it is abundant in meteorites. Scientists believe this impact ended the Cretaceous Period and caused the dinosaur extinction. Is this a theory or a law and why?
It is a theory, because it explains the cause of the dinosaur extinction.
200
what causes the changes measured in an experiment. Written in the first part of the hypothesis after the "If___"
Independant or Test Variable
200
In a controlled scientific experiment, a scientist does what with an independent variable and what with a dependent variable?
alters the test variable (independent variable) and observes the effects on the outcome variable (dependent variable).
300
Debbie is working on a science fair project and needs to determine the variables that she will use. Help Debbie understand the difference between a test variable (independent variable) and an outcome variable (dependent variable)?
The outcome variable (dependent variable) is the result of the changes the researcher makes to the test variable (independent variable).
300
After Steven read an article describing an experiment, he concluded that the experiment was valid. The reasons he thought the experiment was valid was because it included several trials and several other scientists had conducted the same experiment with similar results. True or false: This experiment is valid because it used repetition and replication?
True: The experiment was subjected to both replication and repetition.
300
Biologists study life. Geologists study the Earth. Chemists study matter and its interactions. What similarity exists among scientists working in these fields?
They all gather information to answer questions about the natural world.
300
The atomic theory has been modified many times to explain new experimental data. However, the data has never led to the atomic theory being discarded. Why are theories sometimes modified, but rarely discarded?
Scientists form a theory after they have repeatedly verified the hypotheses leading to the theory by carrying out experiments.
300
the changes that are measured in an experiment. Written after the "then, ________" in the hypothesis.
Dependent or Outcome Variable
300
Lexi is researching crime rates. She is trying to make a conclusion about whether the crime rate changes with the population in each county in her state. What is the outcome variable (dependent variable) of her investigation?
the crime rate
400
Kathleen likes to grow plants in her greenhouse. She wants to find out if the plants will grow more leaves if they are watered more often. She counts the number of leaves on each plant before she starts. She divides the plants into two groups, one group is watered once a day and the other group is watered twice a day. What is the test variable (independent variable) in Kathleen’s experiment?
the number of times the plants are watered
400
when a scientific investigation is reproduced by another person. when someone else does the entire experiment.
Replication
400
Susan noticed that hummingbirds in her yard visited all the flowers, but especially seemed to like the red trumpet-shaped ones. She read that they use the nectar in the flowers for food. She assumed that since the parents were eating nectar, they must feed their babies nectar as well. To her surprise she saw hummingbirds bringing small insects and spiders to feed the young hummingbirds. How does this new evidence affect her original assumption?
She should change her original assumption that they only feed their babies nectar.
400
The current knowledge concerning plate tectonics is the result of the investigations and observations of many scientists. The work of these scientists forms a well-accepted body of knowledge explaining plate tectonics. Does this body of knowledge demonstrate a theory or law and why?
theory
400
a well-substantiated explanation of some aspect of the natural world
Scientific Theory
400
Shakita wants to know if the pH of an open can of soda changes over time. To test this, she designs an experiment that will involve the following steps.
1. Open a can of soda and measure the pH.
2. Allow the open soda can to rest undisturbed on a level countertop at room temperature.
3. Measure the pH of the open soda can every day at the same time for ten consecutive
days.
What is the outcome variable (dependent variable) in Shakita's experiment?
the pH of the soda
500
What is the correct order of the following steps using the scientific method? (list of numbers)
1. Hypothesize
2. Compare results
3. Draw conclusions
4. Count and record data
1, 4, 2, 3
500
How can Scientific knowledge withstand the test of time?
it is open to change as new evidence or data is discovered.
500
Nearly 2,000 years ago the astronomer, Ptolemy, believed that all objects in space, including the Sun, revolved around Earth. Five Hundred years ago, Nicolaus Copernicus made observations showing that Earth and other planets revolved around the Sun, which disproved Ptolemy’s argument. What does this example demonstrate regarding scientific knowledge?
Scientific knowledge changes as a result of new evidence.
500
When Alfred Wegener first published his theory of continental drift, the vast majority of scientists refused to accept the theory. It took 50 years before the theory of continental drift was accepted by the scientific community. What most likely caused geologists to accept Alfred Wegener’s theory?
Scientific knowledge can change when new evidence or interpretations arise.
500
when multiple sets of measurements are made during one scientific investigation
Repetition
500
The production of oxygen from a reactant in a chemical reaction is shown in the graph below.
The graph shows the volume of oxygen produced as a function of the amount of reactant consumed. If the trend continues, how much oxygen will be produced when 25 g of the reactant is consumed?
A. 5.0 ml B. 4.0 ml C. 3.0 ml D. 1.5 ml
5.0 ml
600
Nick is conducting a controlled experiment to test whether music helps daisies grow faster. Below are the steps to Nick's experiment:
1. Plant daisies in two separate flowerpots.
2. Place flowerpot 1 in a green room with music.
3. Place flowerpot 2 in a similar green room without music.
4. Give the daisies the same amount of food and water each week.
5. Measure the growth of the daisies.
6. Draw conclusions based on the data collected.
Which group is the control group in Nick's experiment?
A. flowerpot 2
B. the green room
C. flowerpot 1
D. the music
A. flowerpot 2
600
Raul wants to study how pot size affects the growth of plants. To do this, he intends to purchase three different pots of varying diameter. Then, he will fill each pot with the same amount of soil and plant different kinds of flowers in each pot. Finally, he will place the pots side by side in a sunny location and water each pot daily with the same amount of water. Will Raul's experimental set-up produce valid results? Why or why not?
No; Raul changes more than one variable so the results will be invalid.
600
At one time, most people believed that the Universe was static, meaning it did not change. When larger and better telescopes were invented in the early 1900s, however, it was discovered that light from objects in space shifted toward longer wavelengths. Scientists concluded that only an expanding Universe could explain this shift. How does new evidence or interpretations impact scientific knowledge?
Scientific knowledge can change when new evidence or interpretations arise.
600
A scientist conducts an experiment to test a hypothesis. The experiment confirms that the hypothesis could be true. When will the hypothesis most likely become a scientific theory?
when the hypothesis has survived extensive testing
600
statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena
Scientific Law
600
Jami is doing an experiment to find out how temperature slows down or speeds up the sprouting of bean seeds. To prepare for the experiment, she plans to put soil into three foam cups and place six seeds in each cup. When Jami performs the experiment, which of the following should she keep the same for all of the cups of beans?
I. the amount of sunlight
II. the amount of water
III. the temperature
IV. the amount of fertilizer
I, II, and IV only