A team from Japan and Germany found something new. They found that small amounts of dirt help materials slide better. Small elements like oxygen make sliding easier. The oxygen helps form tiny patterns inside the material. These patterns are like layers. They work like graphite. Graphite slides easily because it has layers.
Engineers usually want to remove dirt from materials. They think dirt causes problems. But this team found that dirt can help. The research was from Osaka Metropolitan University and Fraunhofer Institute. They published their work in a science journal. The team used computer programs to study rubbing.
This discovery can help make machines work better. Less sliding friction means less energy lost. Machines can last longer with less wear. The team found a way to make surfaces that fix themselves. These surfaces stay slippery while machines run.
Sources: phys.org
The words in bold are from the article.
| 1. found | a. tiny |
| 2. small | b. study |
| 3. helps | c. power |
| 4. layers | d. more |
| 5. remove | e. devices |
| 6. work | f. assists |
| 7. machines | g. discovered |
| 8. better | h. take out |
| 9. energy | i. sheets |
| 10. longer | j. improved |
1.g 2.a 3.f 4.i 5.h 6.b 7.e 8.j 9.c 10.d