Sonoluminescence
Most recent answer: 10/22/2007
Q:
I’ve read a little about sonoluminescence and think it looks pretty cool. Is there any way I can reproduce these effects at home? I’ve seen some explainations, but never found a clear explanation.
- Laura Klyber (age 17)
International School, Geneva, Switzerland
- Laura Klyber (age 17)
International School, Geneva, Switzerland
A:
sono = sound, luminescence = light, Sonoluminescence = light caused by sound.
If you take a flask of water, put speakers on the sides of the flask, and turn the volume way up, something interesting can happen. Little bubbles will form. The sound waves push and pull the water so much that the water actually pulls apart. A little bit of vacuum is left behind.
Air that is dissolved in the water then begins to fill the vacuum. Water evaporates into the vacuum. When the bubble tries to collapse, it is now filled with gas. The sound wave that is powerful enough to pull the water apart, also pushes the gas bubble closed with a lot of strength.
For a brief fraction of a second, the gas is compressed so much that it heats up until it glows. What we see is a little flash of light. That light flashes with each wave of sound that hits the bubble. It looks like a continuous spark of light in the middle of the water. Even though the equipment can be bought for a few hundred dollars, getting everything perfect so that it works is difficult. You need a very spherical flask, ultrasonic speakers around the outside surface of the flask and electronics to drive the speakers. Experimenters also put different gasses in the water to see what happens.
EJ
If you take a flask of water, put speakers on the sides of the flask, and turn the volume way up, something interesting can happen. Little bubbles will form. The sound waves push and pull the water so much that the water actually pulls apart. A little bit of vacuum is left behind.
Air that is dissolved in the water then begins to fill the vacuum. Water evaporates into the vacuum. When the bubble tries to collapse, it is now filled with gas. The sound wave that is powerful enough to pull the water apart, also pushes the gas bubble closed with a lot of strength.
For a brief fraction of a second, the gas is compressed so much that it heats up until it glows. What we see is a little flash of light. That light flashes with each wave of sound that hits the bubble. It looks like a continuous spark of light in the middle of the water. Even though the equipment can be bought for a few hundred dollars, getting everything perfect so that it works is difficult. You need a very spherical flask, ultrasonic speakers around the outside surface of the flask and electronics to drive the speakers. Experimenters also put different gasses in the water to see what happens.
EJ
(published on 10/22/2007)