Nature of Science.
Jules wanted to know whether the eating behavior of goldfish is affected by music. He set up a fish tank. Every day, Jules played music for the fish and measured how much the fish ate. What is Jules missing from this experiment? a. A control group b. A measurable result c. Different types of fish d. An outcome variable (dependent variable)
A
.In the past, scientists believed that surface formations on Mars were canals, built by intelligent beings. Scientists later proved that the "canals" were simply natural formations. Which of the following provided evidence that there were only natural formations on Mars? a. Probes were sent to Mars that collected data about the planet's surface. b. Astronauts landed on the Moon and observed different surface conditions there. c. A survey was conducted to see how many people thought there was life on Mars. d. A computer model simulated the formation of landforms using data from geological fieldwork on Earth.
a
In scientific research, scientists should clearly publish the procedures used in their experiments, along with their observations and data. Why is it important for someone else to know the procedure? a. Knowing the procedure allows for replication of the experiment. b. Knowing the procedure helps others understand the reasons for the experiment. c. Knowing the procedure demonstrates the technical proficiency of the scientist. d. Knowing the procedure can explain how the data were interpreted by the scientist.
a
In the 1600s, Francisco Redi tested the hypothesis that life could arise from nothing, an idea called spontaneous generation. He put meat in two open jars and two tightly sealed jars and observed whether new flies were produced in each jar? The results of this experiment provided evidence that spontaneous generation does not occur. Flies were seen only in the uncovered jars. Which best describes how scientists should respond to this evidence? a. Modify the original theory based on the new evidence. b. Disregard the new evidence and keep the original hypothesis. c. Design a new experiment that will prove the hypothesis to be true. d. Collect many opinions on whether or not to accept the new evidence.
a
Sandra uses a lamp to study how varying the quantity of light affects the growth of seedlings of the Florida sweet acacia tree. Miguel varies the amount of water acacia seedlings receive to study the effects of water on the seedlings. Each student designs an experiment and creates a chart to record data. The two charts are shown below. Based on the information in the charts, which of the following would be a step in replicating one of the above experiments? a. Sandra adds 30 milliliters (mL) of water to the third seedling each day. b. Miguel adds 20 milliliters (mL) of water to the second seedling each day. c. Sandra conducts a second and third trial, leaving the lamp on for the same periods of time. d. Miguel adds 30 milliliters (mL) of water to a potted seedling placed 10 centimeters (cm) from a lamp.
a
Gregor Mendel conducted research about genetics by breeding pea plants. Although he could not actually see into cells, he deduced from his results that each of an organism's traits is determined by two factors (alleles). Long after Mendel's work, microscopes were improved and scientists observed that chromosomes in the nucleus occurred in matching pairs. It is now accepted that the two alleles for each trait are located on homologous chromosomes. What does this demonstrate about science? a. Advances in science may result from new interpretations of previous work. b. Improvements in equipment and data gathering can disprove previous conclusions. c. Earlier scientists did not have the proper equipment and materials to make their conclusions. d. Much of early scientific research was faulty because the earlier scientists did not practice the same data-gathering practices as modern scientists.
a
In an 8th grade science class, there are four lab groups. Group 4 designs an experiment to find out how light affects the germination rate of radish seeds. The students in Group 4 write out their procedure and conduct their experiment. They discover inconsistencies in their data and decide to increase the number of trials to obtain multiple data sets. Which of these most accurately describes how this should be done? a. Group 4 should repeat their procedure multiple times. b. Group 4 should repeat a revised procedure multiple times. c. Group 4 should communicate their procedure to another group for replication. d. Group 4 should communicate a revised procedure to another group for replication.
a
Suppose NASA discovers a new planet in a neighboring galaxy. Astronomers want to collect more information about the new planet. Which of the following methods are scientists least likely to use to study the planet? a. Travel to the distant planet and observe it directly. b. Launch satellites into space to take pictures of the planets. c. Make a model of the planet based on data already collected. d. Use a telescope to track the movement of the planet across the sky.
a
The development of microscopes allowed scientists to investigate living things in greater detail. Through many investigations, scientists found evidence that all living things are made of one or more basic units that divide to form new units. Scientists used their evidence to explain the relationship between these "building blocks of life" and the organisms to which they belong. What are these explanations called? a. Cell theory b. Germ theory c. Law of mitosis d. Law of biogenesis
a
The graph below shows which wavelengths, in nanometers (nm), and corresponding colors of light are absorbed by the plant molecule chlorophyll a. Chlorophyll a is one of the molecules that plants use for photosynthesis. Which of the following would be an accurate analysis of the information shown? a. The least effective color of light for photosynthesis appears to be green. b. The lease effective colors of light for photosynthesis appear to be orange and red. c. The most effective wavelengths of light for photosynthesis are between 450 and 550 nm. d. The lease effective wavelengths of light for photosynthesis are between 600 and 700 nm.
a
. Ralph conducted an experiment to study the effect of temperature change on the heart rate of Daphnia, transparent aquatic invertebrates commonly known as water fleas. Ralph heated three different beakers of water containing Daphnia to a different temperature: 30oC, 32oC, and 34oC. He put a drop of water from each beaker on a slide mount. He then used a microscope to observe Daphnia in each sample. He counted the number of heartbeats in one minute and averaged his results. Which of the following could be a step in a replication of this experiment? a. Ralph observing Daphnia in water at 30oC, 32oC, and 34oC. b. Ralph's classmate Mina observing Daphnia in water at 28oC, 26oC, and 24oC. c. Ralph's classmate observing Daphnia in water at 30oC, 32oC and 34oC d. Ralph observing Daphnia in water with different concentrations of dissolved salt at 30oC, 32oC, and 34oC.
b
A group of scientists has been asked to conduct a study on how an oil spill will affect the surrounding sea life. The scientists decide that the best way to complete the study is to create a model. Which of the following is the most likely reason that the scientists will use a model instead of creating an actual oil spill study? a. They think using a model will provide them with more accurate results. b. They can study the effects of an oil spill without harming surrounding sea life. c. They can use different species that the plants and animals found in the real ecosystem. d. They expect the oil spill in their model to have a much greater effect than an oil spill in the natural environment.
b
A group of scientists has been asked to conduct a study on how an oil spill will affect the surrounding sea life. The scientists decide that the best way to complete the study is to create a model. Which of the following is the most likely reason that the scientists will use a model instead of creating an actual oil spill study? a. They think using a model will provide them with more accurate results. b. They can study the effects of an oil spill without harming surrounding sea life. c. They can use different species that the plants and animals found in the real ecosystem. d. They expect the oil spill in their model to have a much greater effect than an oil spill in the natural environment.
b
A group of students want to investigate the effects of plant moisture on the growth of caterpillars. The students fill three identical boxes with an equal number of a kind of leaf that caterpillars eat. The students keep the leaves in the first box dry, spray the leaves in the second box with two sprays of water, and spray the leaves in the third box with four sprays of water. The students then add four caterpillars to each box. Every day the length of each caterpillar is measured and recorded, and the results are averaged. What is the test variable (independent variable) in this experiment? a. The number of leaves put in each box b. The amount of water put on the leaves c. The number of caterpillars in each box d. The change in length of the caterpillars
b
A timeline of some models of atoms throughout history is shown below. These models have contributed to the formation of the atomic theory. Which statement best summarizes the development of the atomic theory over time? A. Advancements in atomic models proved the atomic theory was accurate. B. The discovery of new evidence resulted in changes to the atomic theory. C. With the discovery of every new element, the atomic theory was modified. D. Changes in atomic models showed that the atomic theory was based on opinion.
b
Astronomers send probes to other planets to take pictures of their surfaces. An astronomer thinks that briny water flows on Mars because he noticed certain features in one picture of Mars. Which method did the astronomer use to form this hypothesis? a. Reading scientific literature b. Making careful observations c. Analyzing a natural experiment d. Conducting a controlled experiment
b
Nina wanted to know whether different brands of soda hold different levels of carbonation. She observed people opening sodas over several weeks. Nina concluded that some brands hold more carbonation because they were more likely to foam when opened. Which of the following best describes the evidence Nina gathered through her observations? a. Nina's observations are sufficient to form a scientific conclusion. b. Nina could use her data to form a hypothesis and test it with an experiment. c. The data from Nina's observations led her to an incorrect scientific conclusion. d. Nina should disregard her observations because they did not result from a controlled experiment.
b
. Jason wants to investigate how weather influences the temperature of soil. He takes measurements at the same time and same place in a field for five days and records his results. He also records the weather conditions at the same time of each measurement. Which of the following best describes Jason's investigation? a. It is a successful experiment that tests a hypothesis. b. It is a reliable experiment because he controls variables except for one test variable (independent variable). c. It is an investigation that tests an idea without manipulating a test variable (independent variable). d. It is a successful investigation because the data proved that weather conditions influence soil temperature.
c
A basic principle for scientific research is that the experiment must be able to be replicated. What happens when an experiment is replicated? a. A scientist publisher accepts the experimental results for printing. b. No one in the scientific community agrees with the methods or results. c. Other scientists perform the same experiment and get comparable results. d. The scientific researcher preforms the experiment many times and gets the same results.
c
A scientist spends a month observing two prairie animals, prairie dogs and ferrets, in their natural habitat. Base on his observations, the scientist states that ferrets are more active than prairie dogs. Why is his statement NOT a scientific theory? a. It is an observation of something in nature. b. Prairie dogs and ferrets are different species. c. The statement is not widely accepted and supported by sufficient evidence. d. The scientist has not conducted enough trials to draw a valid conclusion.
c
Jose performs an experiment to determine how much sugar can be dissolved in 250 milliliters (mL) of water at 25oC. He adds 50 grams (g) of sugar at a time to the water while stirring and observes the solution. After adding sugar the eleventh time (550 g), he notes that undissolved sugar has settled to the bottom of the container. He stops adding sugar and ends his experiment. In his lab write-up he concludes that the solubility of sugar in water at 25oC is 500 g per 250 mL. Is his conclusion defensible, and why or why not? a. No, because he did not add sugar enough times. b. Yes, because when he added more than 500 g it did not all dissolve. c. No, because he does not know if any of the final portion of sugar dissolved. d. Yes, because when he added the tenth portion (500 g) all of it dissolved.
c
There are many important laws and theories in science. Which of the following is a law of science? a. A living thing is made of at least one cell. b. An atom is made of electrons orbiting a nucleus. c. Gravity will pull two objects toward each other. d. Natural selection will change species to fit their environments.
c
Two types of models that can be used to sho w details of the structures of cells are shown below. Which of the following describes a limitation of the drawing but NOT the clay model? A. It does not represent the main par ts of a cell. B. It does not contain the cor rect number of nuclei. C.It cannot represent a living cell, since a true cell is three-dimensional. D. It cannot represent a living cell, since the cytoplasm should be in constant motion.
c
Two types of models that can be used to show details of the structures of cells are shown below. Which of the following describes a limitation of the drawing but NOT the clay model? A. It does not represent the main parts of a cell. B. It does not contain the correct number of nuclei. C. It cannot represent a living cell, since a true cell is three-dimensional. D. It cannot represent a living cell, since the cytoplasm should be in constant motion.
c
A meteorologist who has been analyzing weather data from the last fifty years found evidence of climate change. An ecologist has been studying deposits of pollen from the last fifty years to track the types of plants that grew in certain regions. She has also found evidence of climate change. What does this imply about science? a. Meteorology and ecology are the same type of science. b. When scientific disciplines overlap, researchers should choose new topics. c. Different scientific disciplines can be used to investigate similar questions. d. There should be fewer sciences, as they seem to answer the same questions.
c.
Atomic theory, which describes the atoms that make up matter, has been explored for centuries. Scientists in ancient Greece first proposed that matter was made of units called atoms. For many years, scientists thought atoms were solid and could not be divided. Then, in the nineteenth century, scientists began to discover the particles that make up atoms. Modern techniques have allowed scientists to split atoms into increasingly smaller particles. Which of the following statements about theories is supported by the history of the atomic theory? a. If new evidence contradicts earlier theories, it is a result of an experimental error. b. Experiments with modern equipment cannot be used to support earlier theories. c. A theory is discarded when new evidence contradicts a part of the theory. d. Theories can change in response to new evidence.
d
Chemists once believed that an atom was made of negative electrons dispersed inside a positive mass like raisins in pudding. An experiment with radiation and gold foil demonstrated that most of an atom was made of empty space. After this experiment, they adopted a new model of the atom that showed the electrons orbiting the nucleus of the atom from a distance. Which of the following statements about the new model is true? a. The new model is perfect and will not change. b. The new model is a wrong model and will not last. c. The new model fits the data worse than the old model. d. The new model fits the data better than the old model.
d
Denise and David are testing how plants respond to fertilizer. They use three plants for the experiment. The first is given a cup of Fast Grow fertilizer with no water. The second is given a teaspoon of Sunlight fertilizer with a cup of water. The third plant is given no fertilizer with a cup of water. Denise and David will not be able to draw a valid conclusion from their result. Which of the following statements explains why? a. There are not enough different types of plants. b. There is no test variable (independent variable). c. Results of the experiment need to be presented in a graph. d. More than one test variable (independent variable) has been changed in the experiment.
d
During the nineteenth century, biologists knew that South America and Africa contained similar fossils. These fossils let them to believe that a temporary land bridge between South America and Africa allowed ancient species to move between both continents. In the twentieth century, evidence showed that South America and Africa were once part of the same larger continent and that there were no land bridges between them. How should biologists respond to the new geological finding? a. Biologists should reject the geological finding, because it is new. b. Biologists should ask physicists what to do, because physics is a more exact science. c. Biologists should reject the belief in ancient species, because there were no land bridges. d. Biologists should update the history of life, because it should include the new geological finding.
d
Glands regulate distant parts of the human body with hormones. The pancreas regulates the body with a hormone called insulin. A biologist wanted to discover the effects of insulin from the pancreas. The biologist altered the pancreases from 30 mice. The biologist kept another 30 mice unaltered. Then the biologist recorded the differences that developed between the mice in both groups. What method did the biologist perform to investigate the role of the pancreas? a. Publishing finished results b. Reading scientific literature c. Analyzing a natural experiment d. Conducting a controlled experiment
d
In recent scientific history, the classification of protists has changed several times. They now have been regrouped to consider their development over time instead of simply by how they move or look. Which statement best describes such changes in scientific knowledge? a. An entire species must be discovered before a classification system can be made. b. Early ideas about taxonomy should be unchallenged so that scientists can continue to classify new species. c. Modern technology and processes make it possible to prove an idea so further research is not necessary. d. As more knowledge is gained about organisms and natural events, scientific interpretations change as necessary.
d
Maria and Richard are working together to learn about the effects of different lesson types on student participation in the classroom. Maria observes and records the number of students in the class who appear to be paying attention during different types of lessons. Richard interviews and records the answers of five teachers who are asked the same series of questions concerning student participation. Both activities exemplify which of the following parts of the scientific process? a. Maintaining control variables b. Forming a hypothesis c. Making conclusions d. Data collection
d
Scientific knowledge may change as new evidence or information is discovered. Which of the following would NOT be a result of new scientific research and information? A. Binomial nomenclature is assigned to a recently identified plant species. B. An endangered monkey species is put in a reserve for protection from extinction. C. A newly discovered chemical element will be added to the periodic table of the elements. D. A nonnative plant species will begin to reproduce rapidly after being introduced into a swamp ecosystem
d
Scientists create both scientific theories and scientific laws as they make observations and conduct experiments about the natural world. Which of the following statements most accurately compares the difference between scientific theories and scientific laws? a. Scientific laws are based on evidence, while scientific theories are not. b. Scientific theories involve only biology, while laws involve all types of science. c. Scientific theories involve mathematical equations, while scientific laws are based on observations. d. Scientific theories are ideas that explain natural events, while scientific laws more reliably predict natural events.
d
Scientists have studied glaciers in Greenland as evidence of global warming. One team of scientists predicts that glaciers are melting at an accelerated rate. The scientists collect the same types of data on the same glaciers on the same dates each year for ten years. The scientists conclude that the glaciers have decreased in mass and increased their velocity toward the sea each successive year. Which of the following statements best evaluates the process that the scientists used? a. The process is a flawed experiment because the variables are not controlled. b. The process is a valid experiment because there is an independent variable and a test variable. c. The process is a flawed investigation because the investigators did not begin by forming a hypothesis. d. The process is a valid investigation because scientists used systematic methods for collecting and analyzing information.
d
The scientific community communicates its finding to the rest of the world by publishing its work in scientific journals. This enables others to replicate and repeat other scientists' experiments to accept or reject the hypothesis and conclusions of others. However, individual scientists do not submit their work to the scientific community before making sure they are right. How best can they ensure that their results are valid? a. Scientists hire editors to review their lab reports to make sure that their explanations are clear and concise and to change anything that doesn't sound good. b. Scientists partner with mathematicians to check over all their data and charts and graphs to ensure that there is enough data, but if not, they can add to the data. c. Scientists repeat their experiments just a few times to show that they can get the same results more than once and to catch any mistakes in the procedure. d. The scientists repeat their experiments over and over many times to ensure that they have taken everything into consideration to communicate quality results.
d
The validity of scientific theories and laws depends on evidence. Which of the following statements of evidence supports a law rather than a theory? a. Electrons orbit the nucleus of an atom within a certain radius. b. DNA analysis reveals that a modern species is related to an extinct species. c. Seafloor spreading occurs at a rate of three centimeters per year in the mid-Atlantic. d. The amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction.
d
Until the 1500s, doctors thought diseases were caused spontaneously. Scientists began proposing that diseases were caused by seedlike entities that could be passed among people. After the invention of the microscope, doctors came to know that many diseases were actually caused by microscopic living organisms, like bacteria. What does this suggest about the nature of scientific knowledge? a. Scientific knowledge should not be considered valid because it changes over time. b. Technology has improved enough that scientific knowledge can stop changing. c. New discoveries and evidence are more important than repeatable results. d. Scientific knowledge changes over time based on evidence.
d
Scientists create both scientific theories and scientific laws as they make observations and conduct experiments about the natural world. Which of the following statements most accurately compares the difference between scientific theories and scientific laws? a. Scientific laws are based on evidence, while scientific theories are not. b. Scientific theories involve only biology, while laws involve all types of science. c. Scientific theories involve mathematical equations, while scientific laws are based on observations. d. Scientific theories are ideas that explain natural events, while scientific laws more reliably predict natural events.
d.
Keesha did an experiment to study the rate of photosynthesis in the water plant Elodea. She placed a piece of Elodea in a beaker of water and set the beaker 10 centimeters (cm) from a light source. Keesha counted the bubbles released from the plant every minute for five minutes (min). She repeated the process two more times. First, she moved the light to 20 cm from the beaker, and then she moved the light to 30 cm from the beaker. Keesha's setup and data are shown below. What is the outcome variable (dependent variable) in this experiment? F. the number of bubbles produced G. the type of plant placed in the beaker H. the distance of the light source from the plant I. the amount of time the bubbles were counted
f