Heat absorbing tube, bright rough

For detecting the absorption of heat radiation depending on the surface color and the nature of the surface, with different tubes a clear temperature difference can be seen after just a few minutes!
Aluminum tubes with flat bottom and rolled rim, surface bright, rough
Dimensions: D=15 mm, L=100 mm
Mass: 3 g

Additionally recommended:
1 x C7320-1D Stopper, silicone 12/18/27 mm, 1 hole
1 x P2220-1A Graduated laboratory thermometer, -10 ... +110 °C
1 x P2621-1B Mounting bracket for heat absorbing tubes