Blog

Below is a picture of a nearby star-forming molecular cloud in our galaxy. Two southern hemisphere telescopes were used to take the pictures of protostars in this molecular cloud shown below. The next five questions test your understanding of the life of a star. Attributions Images ALMA (ESO/NAOJ/NRAO), J. Tobin; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA. Protostarts in Orion Molecular Clouds [photograph]. (CC BY 3.0). Via NRAO.

You are given two clear solid crystals and told that only one of them is an ionic material. Both of them dissolve in water. How can you tell which one is the ionic material?

The next two questions deal with this situation: A large hammer and small nail are dropped from the same height at the same time. Both are originally at rest. Ignore air friction.

Professor Lawler borrows a spaceship and loads one of the lasers from a physics lab into it. She flies away in a straight line at constant speed going exactly half the speed of light.   As she flies off, she shines a beam of light from the laser back towards the science center and has one of her students measure how fast the light is going. What does the student find?

Where on the periodic table can you find elements that typically will “take” two electrons in chemical reactions?

Which of these statements best describes the forces on the ball and bat? (Bats have more mass than the balls.)

In her devotional talk, “Finding Your Place in the Universe,” Dr. Stephens compared us to stars. What point was she making with this analogy?

Below is a mass spectrum for one of the molecules pictured above. Which molecules produced this spectrum?   

Earths’ mass and volume have been measured, and the planet’s density is about 4.5g/cm3. The rock samples collected on the surface  have densities of 3-4g/cm3 . What does this tell us about the Earth?

In which of these situations does the entropy of the universe increase?