GSC International 7-1113 Radiometer Crookes Style. All Glass Construction.
- Glass Bulb with Vanes: A radiometer consists of a glass bulb that contains a partial vacuum. Inside the bulb are four lightweight vanes (or paddles), mounted on a spindle, which can spin freely. Each vane has one side that is black and the other side that is white.
- Light Energy Conversion: When light shines on the radiometer, the black sides of the vanes absorb more light energy than the white sides. This energy difference causes a temperature gradient, with the black side becoming warmer than the white side.
- Thermal Transpiration Effect: The warmer black side heats up the surrounding gas molecules inside the radiometer, causing them to move more rapidly compared to the molecules near the cooler white side. This difference in molecular movement creates a pressure imbalance, pushing the vanes to spin.
- Vacuum's Role in Movement: The bulb is not a perfect vacuum; it contains a very small amount of gas. The presence of these gas molecules is essential for the radiometer to work. Without them, the vanes would not spin because the pressure difference wouldn't develop. In a total vacuum, the radiometer would remain motionless.
- Effect of Hot or Cold Water: When a radiometer is exposed to hot water, the temperature inside the radiometer increases. The temperature difference causes the gas molecules to move faster on the black side of the vanes, spinning the vanes. If a radiometer is placed near cold water, the internal temperature decreases. The air molecules will move slowly, resulting in a slower rotation or even stop the spinning completely.
PRODUCT WARNINGS
WARNING: This product can expose you to chemicals including styrene and lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
Our products are not toys. Use in a laboratory or educational setting only. Not for children 15 and under.