HUSD 6-8th Science Benchmark 3

" Solar Water Heater Design"

A student is tasked with designing a simple solar water heater. The solar water heater should be designed to meet two goals: 1) increase the temperature of water as much as possible and 2) prevent the water from losing that heat once it enters storage. The design needs to be composed of three main parts: a solar collector, which collects solar energy and heats water; a storage tank, where the water is stored after it is heated; and a connector, which transports the heated water from the solar collector to the storage tank. The only restriction on the design materials is that the student may not use electronics.

The diagram below shows the student's initial design and identifies the materials she used. Note: She elevated the solar collector so that the water would more easily drain into the connector and be transported to the storage tank.

The student set her design up for testing by placing the solar collector outside in direct sunlight and placing the storage tank under shade. After allowing the solar collector to collect heat for an hour, she poured the water into it. She measured the water's change in temperature over the course of an hour. The table shows the results of the test.

"Caramelization"

Caramelization is the process of sucrose (table sugar) being heated until it forms large, brown molecules called caramelans. There are three caramelans: caramelan (C12H12O9), caramelen (C24H26O13), and caramelin (C36H18O24). Before caramelans form, first the sucrose decomposes into glucose and fructose (shown below).

"Geological Columns in Two Locations of a Canyon"

The diagram shows the geological columns in two locations, along with fossils discovered in those layers.

" Types of Genetic Testing"

Genetic testing consists of the processes and techniques used to determine details about your DNA. Depending on the test, it may reveal some information about your ancestry and the health of you and your family. Predictive testing is for those who have a family member with a genetic disorder. The results help to determine a person's risk of developing the specific disorder being tested for. These tests are done before any symptoms present themselves.

Diagnostic testing is used to confirm or rule out a suspected genetic disorder. The results of a diagnostic test may help you make choices about how to treat or manage your health. Pharmacogenomic testing tells you about how you will react to certain medications. It can help inform your healthcare provider about how to best treat your condition and avoid side effects. Reproductive testing is related to starting or growing your family. It includes tests for the biological father and mother to see what genetic variants they carry. The tests can help parents and healthcare providers make decisions before, during, and after pregnancy. Direct-to-consumer testing can be completed at home without a healthcare provider by collecting a DNA sample (e.g., spitting saliva into a tube) and sending it to a company. The company can analyze your DNA and give information about your ancestry, kinship, lifestyle factors, and potential disease risk. Forensic testing is carried out for legal purposes and can be used to identify biological family members, suspects, and victims of crimes and disasters. United States, National Human Genome Research Institute. "Introduction to Genomics." 11 Oct. 2019. Web. 22 Oct. 2020

"Venus's Visibility in the Sky"

When it's visible, Venus is one of the brightest objects in Earth's sky. The planet, which takes about 224 Earth days to orbit the sun, is visible in Earth's night sky for almost ten Earth months as Venus travels from the point of superior solar conjunction toward the point of inferior solar conjunction. It's brightest in the evening as it nears its point of greatest elongation east. Then, as Venus passes the point of inferior solar conjunction, it disappears for a few weeks. It reappears in Earth's morning sky. It's brightest in the morning as it nears its point of greatest elongation west. After approximately eight months in Earth's morning sky, Venus passes out of view again as it reaches the point of superior solar conjunction. Again, Venus remains invisible for a few weeks. When it reappears, it's in the evening sky. The entire cycle takes about 1.6 Earth years. The model below shows these points along Venus's orbit relative to Earth.

The diagram below shows Venus's path through Earth's night sky from August 2019 to June 2020. The diagram also shows Venus's phases (the change in how much of the sunlit portion of Venus is visible from Earth). These phases are not visible to the naked eye, but can be viewed through a telescope. Keep in mind that while Venus was present in the night sky during the entirety of this length of time, Venus didn't become easily viewable to the naked eye until late October. Venus hit its point of greatest elongation east on March 24, 2020. That means that the best time to view Venus in the evening sky was approximately March 24th to April 28th of 2020. On June 3rd, the planet passed its point of inferior solar conjunction. By the third week of June, Venus became visible in the morning sky.

"Lemming Predation"

In the Arctic tundra of Greenland, the population of a small rodent called the collard lemming has long been observed to experience approximately four-year cycles of peaks and lows. Factors such as food availability and space do not seem to be responsible for this cycle. What does seem to be responsible, according to a research study published in 2003, is the interplay between four species that prey on collard lemmings: two mammals, the arctic fox and the stoat (a type of weasel), and two bird species, the snowy owl and the long-tailed skua.

The researchers studied the relationship between lemming density (estimated number of lemmings per hectare) and the daily predation rate (lemmings eaten per day per individuals within a species). The arctic fox, snowy owl, and long-tailed skua, all of which are migratory animals, are generalist predators. When lemmings are abundant in spring and summer, these predators prey on them. When lemmings are more scarce in spring and summer, these predators turn to other prey.

Stoats, on the other hand, remain in Greenland year-round, and they are specialist predators that prey exclusively on lemmings. They burrow under the snow into the lemmings' dens to hunt them during winter when the lemmings are not active.

When the lemming population reaches its peak, the generalist predators prey heavily on lemmings, keeping their population in check as the stoat population grows toward its peak. Once the stoat population reaches its peak, however, the stoat is the main limiting factor on the lemming population. Within a few years, the lemming population plummets. As the generalist predators turn their attention to other prey, the lemming population begins to increase again.

"Parts of a Kidney"

The diagram shows some of the parts of a kidney, as well as where it connects to a ureter. As the kidneys remove waste from the blood, that waste travels down the ureters to the bladder.

"Climate Change Indicators"

(excerpted and adapted)

Earth's climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events, such as heavy rainstorms and record high temperatures, are already happening. Many of these observed changes are linked to the rising levels of carbon dioxide and other greenhouse gases in our atmosphere, caused by human activities. The Environmental Protection Agency (EPA) partners with more than 50 data contributors from various government agencies, academic institutions, and other organizations to compile a key set of indicators related to the causes and effects of climate change. Indicators represent the state or trend of certain environmental or societal conditions over a given area and a specified period of time. EPA's indicators are designed to help readers understand observed long-term trends related to the causes and effects of climate change. In other words, they provide important evidence of "what climate change looks like."

United States. Environmental Protection Agency. "Climate Change Indicators in the United States." Updated July 2021. Web. 10 Dec. 2021