Astronomers have developed several ways to measure the vast distances between Earth and the stars and galaxies. What do you know about two of these techniques? A. An astronomical unit is about 93 million kilometers.

B. The A. U. is used to measure distance within our solar system.

C. A light-year (ly) is the distance that light can travel in one year in a vacuum.

D. An astronomical unit (A. U.) is the average distance between the Earth and the Sun.

E. Astronomers measure distances to objects which are outside our solar system in light-years.

Using the periodic table, complete the table to describe each atom. type in your answers

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

What are transitions between a liquid and gas called? identify which way they are transitioning