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8.P4U1.3
Which model of a chemical reaction best illustrates the conservation of mass? DOK 2
A design for a hand warmer is shown below. When the metal disk is bent, the dissolved chemicals begin crystallizing around the disk and spread throughout the container. As the chemicals crystallize, they release heat. However, the container gets so hot that it is uncomfortable against skin. DOK 2 Which design modification would best address this problem?
The picture shows fossils preserved in rock layers at three locations. DOK 2 Which fossil may best be used as an index fossil?
"Gummy Bear Genetics"
Students are learning about genetics using gummy bear models. Their teacher gives them the following table, which shows the colors (green, clear) and sexes (male, female) for three generations of gummy bears.
"Methods of Artificial Selection"
A student researched various technologies associated with artificial selection, the practice by which humans influence the inheritance of traits in plants and animals. His notes are shown below. Genetic Modification
the process by which scientists identify and edit the gene in question, copy it, and place it into a new organism
results in organisms with traits that humans find useful but that do not occur in nature, such as plants that are resistant to pesticides
reduces genetic diversity over time
Selective Breeding
the process by which scientists mate plants or animals intentionally
results in offspring displaying desirable traits, such as plants that produce more food in less time
reduces genetic diversity over time
Animal Husbandry
closely related to selective breeding, but only applies to the production and care of domestic animals, such as livestock or pets
scientists mate animals with desirable traits, such as cows that produce more milk or dogs that don't shed fur
reduces genetic diversity over time
Gene Therapy
closely related to genetic modification, but differs in that the goal is to use genes to treat or prevent disease
scientists alter genes to correct genetic defects
reduces the need for people to rely on drugs or surgery
reduces genetic diversity over time
Some scientists believe that Deccan volcanism at the end of the Cretaceous Period released massive amounts of carbon dioxide, sulfur dioxide, and chlorine in a short period of time.
In which two ways may this have most likely contributed to the mass extinction event at that time? DOK 2
A diagram of the rock cycle is below. Gabbro is a type of igneous rock. Click on the igneous rock that is where gabbro belongs. DOK 2
Where is a geologic hotspot most likely located? DOK 2
Two clear liquids are mixed together in a beaker. DOK 1 What evidence suggests that a chemical reaction occurred?
Classify the descriptions of heat transfer by clicking and dragging each into the appropriate box. DOK 2
an egg cooking in a hot fry pan
sunlight warming a swimming pool
a column of warm ocean water rising from a volcanic vent
a cup becoming hot when boiling water is poured into it
Convection
Conduction
Radiation
Which wave carries the most energy? DOK 2
"Compression and Volume in a Syringe"
A student noticed that when he squeezed on an air-filled latex balloon, the balloon's shape changed. Where he compressed the balloon between his hands, the volume of air decreased. However, that air pushed outward, causing the balloon to expand in other places. He made the same observations when he filled a latex balloon with water and compressed it between his hands. It was difficult to see whether the overall volume of the gas or water actually changed.
To better understand how compression affects the volume of gases and liquids, the student conducted investigations with a 3-milliliter (mL) plastic syringe (shown in Figure 1).
He removed the cap from the syringe and pressed the syringe's plunger all the way in to the 0-mL line. Then he filled the syringe with air by pulling the plunger out to the 3-mL line (shown in Figure 2). He immediately pressed a finger against the tip of the syringe to prevent air from escaping. Then, with his finger still pressed firmly over the tip, he pressed the plunger in as far as it would go (shown in Figure 3). The plunger stopped at the 1.5-mL line.
With his finger still on the syringe's tip, he let go of the plunger. The plunger slowly moved back, stopping when it reached the 2.8-mL line.
The student repeated his investigation, but this time he filled the syringe with water rather than air. When he tried to compress the water by pushing the plunger back in, the plunger would not move.
"Ramp Investigation"
Students wanted to observe how gravity affects the speed of falling objects. Because they struggled to measure the distance traveled by a falling object at different time intervals, they decided to observe gravity's effect on the speed of an object rolling down a ramp. They made a 1-meter ramp by cutting a PVC pipe in half lengthwise. They made 1-centimeter tick marks along the ramp to help them identify the distance traveled. They rolled a 45.9-gram golf ball down the ramp and videoed its progress along the ramp. They played the video back in slow motion so they could record the distance the ball traveled at different time intervals. They conducted three trials. Their data is shown below.
"Earth's Carbon Cycle"
A student studied the carbon cycle for a class project. She learned that carbon is nearly everywhere on Earth. It is found in gases, such as carbon dioxide, which organisms produce when they breathe. It is found in minerals, such as calcium carbonate, which makes up marine organisms' shells. It is found in fossil fuels, such as coal and oil. Carbon, like water, cycles around Earth. It is stored in various reservoirs and moves between those reservoirs. When carbon moves between reservoirs, it is called a "flux."
The student made a model to show carbon fluxes on Earth, shown below. The boxes represent different reservoirs. The numbers in each box show the approximate amount of carbon in that reservoir. The carbon is measured in gigatons of carbon (GtC). For example, Earth's atmosphere contains approximately 760 gigatons of carbon. The arrows represent carbon fluxes, measured in gigatons of carbon per year. For example, burning fossil fuels moves approximately 7 gigatons of carbon into the atmosphere each year. Because carbon is constantly fluxing between reservoirs, the numbers in the model are the best estimates based on current data.
"Sun-Earth-Moon Model"
In the model, the light bulb represents the sun. A polystyrene ball on a stick represents the moon. The boy's head represents Earth. The top of the boy's head is the North Pole. Between his eyes is a city in North America. Whatever the boy can see is what the people in the city can see.
Polar-orbiting satellites circle Earth in a nearly north-south orbit. Their orbits are matched with the sun so that they pass the same point on Earth at the same time each day. DOK 2 How have these polar-orbiting satellites most likely improved weather forecasting?
The diagram shows how two pith balls behaved before and after they were touched by a glass rod that had built up a static charge. DOK 2
Which best explains why the pith balls are not touching at step 3?
"Hydrogen Fuel Cells"
Hydrogen fuel cells combine oxygen gas and hydrogen gas to produce electricity. The oxygen atoms react with the hydrogen atoms across an electrochemical cell, similar to a battery. This process produces electricity, water, and small amounts of heat. Hydrogen fuel cells are a promising energy source for many reasons. Hydrogen is the most abundant element on Earth. Hydrogen fuel cells don't produce pollutants, and they are more efficient than traditional combustion technology (such as that of combustion engines used in most vehicles).
Models of light rays striking three different surfaces are shown below. Complete the table by matching each ray to the effect that the surface has on the ray. DOK 2
Ray 1 | Ray 2 | Ray 3 | |
|---|---|---|---|
diffracted | |||
reflected | |||
absorbed |
from "Gummy Bear Genetics" DOK 2 Assume that a student wants to model speciation with the gummy bears.
For two populations of gummy bears to evolve into separate species, what two conditions would have to be met?
Which best explains the correct answer to the previous question? DOK 2
Which best explains the correct answer? DOK 2
from "Compression and Volume in a Syringe" DOK 2 Which two statements best explain why the syringe is better than the balloon for investigating how compression affects volume?
from "Compression and Volume in a Syringe" DOK 2 Which best explains why the plastic syringe is more rigid than the latex balloon?
"The Reintroduction of Wolves in Yellowstone"
Yellowstone became America's first national park in 1872. While the lands within the park were federally protected, the animals were not. In fact, visitors were allowed to kill any animals they wished. Because wolves are apex predators, the top of the food chain, many people considered them to be pests and eagerly hunted them.
By the early to mid 20th century, humans had killed off the wolves in and around Yellowstone National Park, and in much of the rest of the United States as well. This single change in the greater Yellowstone ecosystem led to changes in many other populations in Yellowstone, thus causing what scientists call trophic cascades. One such cascade involved coyotes. As wolves disappeared, coyotes gained more hunting territory. What's advantageous for coyotes, of course, is disadvantageous for their prey, such as mice, rabbits, and other small mammals.
Another trophic cascade involved elk. Since wolves are the main predators of elk, the disappearance of wolves caused the elk population to increase. The consequences of elk population's growth wasn't only that elk consumed more vegetation, but also, without pressure to keep moving to avoid being hunted by wolves, elk began to stay put all winter, leading to overgrazing in some areas. Two of the plants elk overgrazed were willows and aspen, trees beavers rely on for food and for building materials for their homes and their dams. Thus, eventually, beavers started to disappear from Yellowstone, too. As beavers disappeared, so did their ponds. A lack of beaver ponds increased stream erosion. The disappearance of beaver ponds also meant a decrease in fish and amphibian species that relied on those ponds. Also, since the ponds are important to the growth of willow and other trees, those trees became even less plentiful. The decrease in trees led to a decrease in songbirds in Yellowstone.
In 1995, conservationists reintroduced the wolf back into Yellowstone. They relocated 14 wolves from Canada to Yellowstone the first year of the project. In 1996, they brought in 17 more wolves. The wolf population has increased naturally since then. Over time, various direct and indirect changes have been observed. One such change, as the graph shows, is that the elk population decreased.
In turn, willows, aspen, and other plants began to thrive and replenish. Beaver dams appeared, and the ponds those dams created brought back fish and amphibian species and further contributed to the health of willows and other wetland trees. Songbirds returned. To say that Yellowstone has recovered from the damage done by hunters is an overstatement, but reintroducing the wolf has led to some significant changes to the ecosystem as a whole.
from "The Reintroduction of Wolves in Yellowstone" DOK 2 Which shows a food chain in the Yellowstone ecosystem?
from "The Reintroduction of Wolves in Yellowstone" DOK 2
A student created the model to show the interdependence of some Yellowstone organisms and their environment.
Which two labels best complete the model?
