Melting & Boiling Points of Metals
Believe it or not, metals are solids that melt when sufficient heat is applied. To melt means to change from a solid to a liquid. You have observed melting when ice changes to water if left outside of a freezer. If the water continues to be heated, it will boil and become water vapor, a type of gas. The graph below shows melting and boiling points of 20 different metals.
For example the last metal shown is Zinc. The lower gray portion of the bar indicates that zinc melts around 450 degrees Celsius. (We must estimate because the graph does is marked in 500 degree increments. The orange part of the Zinc bar indicates that as the temperature rises, it will boil around 950 degrees Celsius. Answer the questions below the graph.
Questions for all grade-levels:
1-Which metal appears to have the highest melting point? Hint: look at the gray portion of the bars, only.
2-Which metal appears to have the lowest melting point?
3-Which 3 metals melt around 1500 degrees Celsius?
4-Which 3 metals boil at less than 1000 degrees Celsius?
5-Look at Tungsten. The temperature of Tungsten must rise almost 3500 degrees before it melts. How much more would the temperature need to rise before it boils?
6-At 2000 degrees Celsius, which metals would still be in their solid form?
Questions to students in grades 6-12:
7-Recall that Copper, Silver and Gold are in the same group (vertical column) which means they share certain characteristics. How do the melting points and boiling points of these metals compare? Which statements are true, which are false?
A. Gold has a higher boiling point than Silver or Copper.
B. Silver has a higher melting point than Gold or Copper.
C. All 3 have the same melting and boiling points.
D. Copper and Gold have nearly the same melting points.
E. Silver has a slightly lower melting point than Gold or Copper.
F. At 1200 degrees Celsius, all three would be solids.
8-Look at Mercury on the graph. What is its abbreviation? What is special about Mercury that makes it's graph make sense?
9-Do some quick research to find out a common use for Tungsten. Notice its melting point. Why is tungsten suitable for it's most common use?
10-Aluminum, Tin, and Lead are often called "poor metals." Based on this graph, why might they be "poor?"
2/8/2023 03:07:37 pm
Leave a Reply.