10.thermal properties of matter

04.13.2020
08:34:47
Dear students, good morning
Today's topic : thermal expansion in physics course book pg no : 137 & 138
The important points are
1.Most substances - solid , liquid and gas - expand when they are heated.look at figure 10.8
2.Uses of expansion
* Rivets are used in ship industry and other industries to join metal plates.
* Red hot rivet is passed through holes in two metal plates and then hammered until the end are rounded
* As the rivet cools ,it contracts and pulls the two plates tightly together look at figure 10.9
3. Consequences of expansion
* The expansion of materials can cause problems
* For example , metals bridges and railway lines expand on hot days,and there is a danger that they might buckle.
* To avoid this, bridges are made in section with expansion joints between the section look at figure 10.11
No homework
For better understanding watch the below videos