Questions for ‘Scientists vote to fix the world’s weight-loss problem’


Starting in May 2019, the kilogram will be defined by measurements from a device called the Kibble balance. This is a LEGO model of that device, at the National Institutes of Standards and Technology.


To accompany feature “Scientists vote to fix the world’s weight-loss problem” 


Before Reading:

1.  What is mass? How is it measured? What units are used?

2.  Other than mass, what are three other types of things that can be measured? Now give the commonly used unit for each.

During Reading:

1.  What is Le Grand K? Where can it be found? What is its other name?

2.  What are scientists voting about this month?

3.  Why would it be bad if someone dropped the IPK?

4.  What is the metric system?

5.  Why is the meter no longer defined by a copper rod? How is it defined now?

6.  What is metrology?

7.  Who was Max Planck?

8.  What is Le Grand K made of?

9.  Why did scientists make a perfect sphere of silicon?

10.  Why is defining a kilogram with a Kibble balance better than the current method that is used?

After Reading:

1.  The Kibble balance can measure mass to incredible accuracy, but most people will never use it. Why not? Why will the scales we currently use still be adequate?

2.  Metrologists are discussing the possibility of changing the definition of the second. This won’t be the first time that the definition has changed. Why might scientists need a new definition?