Directions: Ask students to define key vocabulary to gain some scientific background knowledge and to better understand the concepts covered in SN’s Top 10 science stories. Once students answer the questions listed below, they can work in groups to identify other terms and concepts that need further explanation, define those terms and present the findings to the class in a creative way — such as a poster, infographic, commercial, skit or story.

Environmental Science

Story 1. “Half a degree stole the climate spotlight”

What are greenhouse gases?

Greenhouse gases are gases that contribute to the greenhouse gas effect by absorbing heat that would otherwise be transported back into space. Carbon dioxide (CO₂), methane (CH₄) and water vapor are examples of greenhouse gases.

What is carbon capture?

Carbon capture is the transfer of carbon dioxide emissions from human sources such as power plants to long-term storage somewhere else. Proposed methods of CO₂ capture and storage include growing large quantities of extra plants, injecting CO₂ into the ground or storing CO₂ at the bottom of the ocean.

Biological Sciences

Story 2. “Claim of first gene-edited babies sounded alarms”

What is CRISPR/Cas9?

CRISPR/Cas9 is a gene-editing tool that is used to alter the DNA of cells or organisms. CRISPR is an abbreviation — pronounced crisper — for the term “clustered regularly interspaced short palindromic repeats.” CRISPRs are pieces of RNA, an information-carrying molecule. They are copied from the genetic material of viruses that infect bacteria. When a bacterium encounters a virus that it was previously exposed to, it produces an RNA copy of the CRISPR that contains that virus’s genetic information. The RNA then guides an enzyme, called Cas9, to cut up the virus and make it harmless. Scientists are now building their own versions of CRISPR RNAs. These lab-made RNAs guide the enzyme to cut specific genes in other organisms. Scientists use them, like genetic scissors, to edit — or alter — specific genes so that the scientists can study how the genes work, repair damage to broken genes, insert new genes or disable harmful ones.

What are “designer babies”?

Designer baby is the nickname used for a child whose DNA has been altered to remove unfavorable traits (such as disease-causing versions of genes) and/or add favorable traits (such as gene versions for higher intelligence or preferred physical characteristics). Genetically altering human embryos poses ethical concerns.

Story 3. “Crime solvers embraced genetic genealogy”

What is DNA fingerprinting?

DNA fingerprinting is the use of DNA to find out the identity of a person or to discover the relationship between different organisms. In DNA fingerprinting, scientists study the patterns of DNA molecules in specific genes and compare them. In particular, there are several regions called short tandem repeat (STR) loci, also called microsatellites or variable number of tandem repeats (VNTR). At each STR locus, a short DNA sequence — typically four or five nucleotides long — is repeated several times in a row. Different people have different numbers of repeats at each STR locus. Two unrelated people might have the same number of repeats at one STR locus, but the odds of having the same numbers of repeats at many different STR loci are astronomically low, similar to the odds of having the same fingerprint.

Story 6. “We nudged closer to the Mosquito Terminator”

What is a gene drive?

A gene drive is a technique for introducing new bits of DNA into a gene to change the gene’s function. Unlike other such genetic engineering techniques, gene drives are self-propagating. That means they make more of themselves, becoming part of every unaltered target gene they encounter. As a result, gene drives get passed on to more than 50 percent of an altered animal’s offspring, “driving” themselves quickly into populations.

What is a disease vector?

A vector is an organism that can spread disease, such as by transmitting a germ from one host to another. Many disease vectors are insects. For example, mosquitoes can spread malaria-causing protozoa, the Zika virus, and other pathogens from one person to another.

Story 7. “Researchers sent mixed messages about drinking”

What is a meta-analysis?

A meta-analysis is a technique in which scientists pool a large number of previous scientific studies on a single topic and try to identify patterns among them. Meta-analyses allow scientists to look at many studies at once and so work with a large amount of data. But the studies also can be biased. They rely only on data that has already been published (and so might ignore studies that weren’t published because the researchers didn’t find anything). In addition, most scientists don’t do studies in exactly the same way. The tiny differences between studies could affect the conclusions. Finally, with so many papers pooled together, a meta-analysis might pull out effects that aren’t really there at all. But if done correctly, these tests can serve a purpose.

What is the liver?

The liver is an organ in the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, break down harmful substances for excretion by the body, and secrete bile — a greenish fluid released into the gut, where it helps digest fats and neutralize acids.

Story 9. “Paralysis became less permanent with electricity”

What is a spinal cord injury?

A spinal injury is damage to the spinal cord, a cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain. Spinal injuries may result from automobile or motorcycle accidents, sports accidents, serious falls, bullet wounds or other types of accidents. An injury to the lower part of the spinal cord is likely to affect only the lowermost parts of the body, such as the legs (paraplegia). An injury higher up on the spine can affect both the legs and arms (quadriplegia). An injury even higher can affect most bodily functions, even breathing.

Story 10. “Human smarts got a surprisingly early start”

What are hominids?

Hominids are primates within the animal family that includes humans and their ancient upright-walking relatives. Hominids split off from other apes in Africa, most recently from a shared ancestor with chimpanzees. The genus Homo includes modern humans, Homo sapiens, as well as a number of earlier species and subspecies. All hominids except humans are known only from fossils. 

Physics and Astronomy

Story 4. “Neutrino discovery ushered in a new era of astronomy”

What are neutrinos?

Neutrinos are nearly massless subatomic particles. Neutrinos rarely react with normal matter — they do not experience electromagnetic interactions with other matter (they have no electric charge), strong nuclear force interactions with other matter or much gravitational interaction with other matter.

What are blazars?

Blazars are bright and distant active galaxies that shoot powerful jets of radiation from their centers directly toward Earth.

Story 5. “Crater renewed debate over an ancient climate mystery”

What is a meteorite?

A meteorite is a lump of rock or metal from space that passes through Earth’s atmosphere and collides with the ground. Meteorites can be made of different materials including iron, nickel and silicates.

What is a comet?

A comet is a celestial object consisting of a nucleus of ice and dust. Scientists think that most comets originate in the Oort cloud, a cloud of dust and debris thought to exist at the outer edge of the solar system. Comets that get close enough to the sun begin to melt, creating a visible tail that is pushed away from the sun by the solar wind.  

Story 8. “A buried lake on Mars excited and baffled scientists”

What is freezing point depression?

Freezing point depression is the lowering of the temperature at which a solution freezes. When a solute dissolves in a solvent, the freezing point of the solution is lower than the freezing point of the pure solvent. The extent to which the freezing point of a solution decreases depends on the number of dissolved solute particles.  

What is an insulator?

An insulator is a material that does not readily allow heat, electricity, light or sound to pass through it. Air, glass, rubber and wood are examples of common insulators.