Le Grande K, that carefully protected kilogram in Paris, is now in a museum. How does that affect you? Or science? Does it matter that temperature measurements are now linked to Boltzmann’s Constant, or distance to the speed of light (C)?

Answers—no matter how accurate or precise—almost often lead to new questions. In this activity you’ll look at one ongoing astronomical exploration to examine how a bit more accuracy or precision would add to the information we can obtain. Then you’ll speculate on the potential of improved measurement to answer other questions that puzzle scientists today.

Our Mission’s role models admit that we don’t really know the path that these better measurements will provide. Like all pure science, these investigations will lead to insights that will become the foundations of tomorrow’s science and technology in ways that we cannot yet measure.

Materials:

• Calculator
• Video projection
• Online discussion platform optional

Safety Notes:

There are no anticipated safety risks associated with this activity.

In a Galaxy Far, Far Away

It’s not exactly a household word, but MACS0647-JD should be! It is the farthest known galaxy from the Earth based on the photometric redshift. That’s a way of measuring distance that uses changes in the spectral lines emitted by stars. By that measure, MACS0647-JD is 13.26 billion light-years away! 

Visit that galaxy far, far away here:

Use a calculator to convert the distance to the galaxy to kilometers. 1.25449286066e+23

Now imagine that previous estimates of red shift calculations of distance to the galaxy were 99.999 percent accurate. Convert the potential error of the measurement in kilometers. 0.00125449286066‬ e+23  This incredibly large number won’t be concrete to students. It’s enough to simply appreciate it.

Create a table which identifies four astronomical phenomena (planets, stars, galaxies, etc.) and research the distance to each. Then calculate the equivalent of an error of .001 percent would represent.

Think!        

• Why do astronomers use light rather than kilometers as their standard for describing distance? It is a constant, and given the magnitude of differences, it is clearer.
• The movement of an astronomical body changes the wavelength of the light it emits. It’s analogous to how the movement of a train changes the wavelength of the sound its horn emits. Red shift is the term for this change. When distance is measured by “red shift” what instruments would provide the precision? . We can compare the light we see to the light the star emits to estimate its movement with a spectrometer.

Ask and You Shall Measure

There are many other questions that fascinate scientists and all of humanity. In your group, discuss these questions:

• What measurement units are most important to find answers?
• How does greater accuracy bring us closer to answers?
• How might we encourage worldwide cooperation in research?
• What value might answers bring us?

Answers to the second question in each section below will vary. Encourage creativity, as this is an exercise in imagination.

Searching for Missing Mass

For at least 30 years, scientists have agreed on a value for how much matter should be in the universe. They base that estimate on complex calculations of the force and energy in the original “Big Bang.” But there is a big problem: about half of the mass they expected to find was missing! Recently, evidence has emerged to identify the missing mass as baryonic matter, particles in deep space. The particles are scarce (imagine a couple atoms in a big classroom). But when the energy from fast radio bursts is observed, it appears to make these particles glow so that they can be detected.

• What constant(s) could be used to quantify it?  Planck’s Constant, Avogadro’s Number
• Why might it be important to locate that missing mass?

Read more about baryonic matter: Web Link - Cosmic bursts unveil universe's missing matter

Surf’s Up

A tsunami is a wave that is propelled by the energy of tectonic movement thousands of miles across the ocean. It may be only a few centimeters high in the open ocean, but wreaks havoc when it hits the shoreline. Most of the wave and its energy is under the water, with a large amplitude. Detecting tsunamis and predicting their landfall are vital tasks that require international cooperation.

Dart buoys scattered throughout the ocean send signals to satellites, recording sound waves through water. Computer analysis is required to integrate the data and predict landfall. Time is of the essence, coordinating buoys, GPS, and land-based stations.

• What units and tools would be used to standardize these measurements? Second, defined by the atomic clock at the Marine Observatory. (See Lesson 1 Extend.)[a] 
• How can more accurate time measurements improve coordination in early warning systems?

Read more about efforts to detect tsunamis:

• Web Link - Detecting tsunamis
• Web Link - UNESCO Intergovernmental Oceanographic Commission Tsunami Programme  

Tiny Menace

A global pandemic can threaten the health of millions of people. Most epidemiologists believe that the viruses that cause acute respiratory disease like COVID-19 spread by tiny virus particles carried on dust or moisture droplets. The size of these particles might help them determine the range at which the disease can spread.

Measurements of the density of particles in various environments require highly accurate determinations of mass and volume

• What units and constants would be used to define the particles?  For mass, micrograms and Planck’s constant. For volume, micrometers and C.
• How could more accurate density standards speed the integration of research from international sites?

Read more about how coronavirus spreads through the air: Web Link - How Coronavirus Spreads through the Air: What We Know So Far

Ready for Take Off?

Jet aircraft and space vehicles may be manufactured in different sites, and at different times. But each part must be assembled with identical precision. The bolts that hold the plane or spacecraft together must be able to resist extremes of temperature, pressure, and vibration. That means that manufacturers must measure the torque (force used to rotate each bolt as it is attached) to assure that they are all the same.

Improvements in measurement and the application of torque can make aircraft safer and more able to maneuver in difficult environments.

• What is the unit of torque? What are the constants which define it? Newton metre, N m (m2 kg s-2 )[b].involves mass Planck’s Constant and Distance C
• How could international airplane manufacture be improved?

Read more about the importance of torque: Web Link - Talk the torque