Neutrino-detection issues? Time to tree-cruit!

This exercise is a part of Educator Guide: Forest Neutrino Detectors and 3D Vertebrate Anatomy / View Guide
An image of a forest
Forests could be used to detect neutrinos, one scientist proposes. The trees could pick up radio waves produced as a result of interactions of the subatomic particles inside Earth.Kevin Skipworth/500px/Getty Images

Directions for teachers:

To engage students before reading the article, have them answer the “Before Reading” questions as a warmup in class. Then, instruct students to read the online Science News article “Forests might serve as enormous neutrino detectors.” Afterward, have them answer the “During Reading” questions.

As an optional extension, instruct students to answer the “After Reading” questions as a class discussion or as homework.

For background information on neutrinos, visit this webpage from the Fermi National Accelerator Laboratory and/or have students read the Science News Explores article “Let’s learn about ‘ghost particles.’” It’s written at a middle-school reading level.

A version of this article also appears in the April 6 issue of Science News. Then post this set of questions without answers for your students using this link.

Directions for students:

Read the online Science News article “Forests might serve as enormous neutrino detectors.” Then answer the following questions as directed by your teacher.

Before Reading

1. Electrons are an example of a “fundamental particle.” That means that you can’t break them down into anything smaller. And they’re small — about one-two-thousandth the size of a proton or neutron. The neutrino is another fundamental particle. How do you think the size of a neutrino might compare to a proton? Explain how you arrived at your answer.

Answers will vary. However, many will likely say that the neutrino is smaller than the proton because it is a fundamental particle, like electrons.

2. Imagine you’re sitting next to a campfire with your eyes closed. You cannot see the fire, but you probably know it is there. Explain how at least two senses other than vision indicate the fire’s presence.

You can sense the fire’s presence with other primary senses. For instance, you can feel the heat, smell the smoke and perhaps hear the fire’s crackling.

3. Consider the different ways scientists detect things invisible to our eyes. Give two examples of scientific tools or equipment that detect a force or some other such presence. State what each tool detects and give an example of a scientific discipline that might use such tools.

Students may point to things like thermometers (temperature isn’t directly visible), wind vanes or any other such tool. An example of a scientific discipline using a tool might be a chemist using a thermometer to measure the temperature change of an exothermic reaction.

During Reading

1. In what way might trees act as “natural antennas?”

Trees might act as “natural antennas” by detecting radio waves produced by certain interactions of subatomic particles.

2. How do you think the “IceCube” Neutrino Observatory got its name?

The observatory operates on a cubic kilometer of Antarctic ice, which explains the “IceCube” part of the name.

3. What body of water will the Cubic Kilometre Neutrino Telescope study, once it’s complete?

The Cubic Kilometre Neutrino Telescope will search for neutrinos in the Mediterranean Sea.

4. Scientists aim to detect high-energy neutrinos, such as the tau neutrino. Explain the relationship between the tau neutrino and the tau lepton. How might the tau lepton help us to detect tau neutrinos?

The tau lepton could help us detect tau neutrinos because as this particle passes back out of Earth’s atmosphere, it decays and produces distinctive radio waves.

5. Give one example of a question that scientists need to answer before they can determine whether this new tree-detecting method is plausible.

Possible answers include the following: How do trees perform when detecting high-energy radio waves? What is the range of these neutrino detectors? How will trees respond to different types of radio waves? Since trees cannot be precisely built to detect specific radio waves, how will they respond to factors such as radio wave polarization? How might seasons, foliage and leaf dropping affect their sensitivity to the radio waves?

After Reading

1. Imagine you are a scientist who plans to investigate whether the proposed idea will work. The best place to start would be to pick one of the questions that need answering, as described in this article. Which question would you pick? Now summarize how you might design an experiment to address this question. Identify three variables that would be important to consider in this experiment. (Variables are factors that could change the outcome of an experiment, such as temperature.) Then, pick one of these variables and briefly explain how you might conduct an experiment that controls for this variable.

Possible scientific questions could include the effects of seasonal or foliage changes, tree responses to radio wave polarization and more. Variables might list foliage, temperature, season, tree type and more. Controlling for seasonal variation in foliage could be as simple as stating that all experiments occur during the same season.

2. This article describes a scientific proposal, not a scientific study. Briefly describe how the goal of a proposal differs from that of a journal article presenting results of a scientific study. Which would provide more in the form of conclusions: a proposal or a study? Explain your answer.

A proposal aims to suggest to the scientific community that research be carried out to investigate some idea. In contrast, the goal of a scientific study is primarily to investigate some idea (usually through use of experiments that yield quantifiable data), then offer conclusions based on those data.