Aerogel, as its name suggests, is a kind of gel filled with gas. Aerogel is divided into carbon aerogel and silicon aerogel. The minimum density that silicon aerogel can achieve at present is 3 grams per cubic centimeter, which is denser than air. The smallest density of carbon aerogel is 0.16 mg per cubic centimeter studied by Zhejiang University, which is less dense than air. Does aerogel have a Tyndall effect? Let's find out.
1. what is the density of the aerogel
Aerogel is a solid substance and also the world's least dense solid, with a density of only 3 kilograms per cubic meter. Currently, the lightest aerogel is an "all-carbon aerogel" with a density of just 0.16mg/cm3 (minus the air density), which is only 1/6 of the density of air, and when this material is placed on a flower, the soft stamens are barely deformed. Because the aerogel is slightly less dense than air, it is also called frozen smoke or blue smoke, and the particles inside it are very small, only on the nanometer scale, so the scattering of visible light is very weak, just like sunlight passing directly through air.

2. does aerogel have the Tyndall effect
Aerogel can produce the Tyndall effect. The Tyndall effect refers to the fact that under certain conditions, a change in the concentration of a substance will change its surface tension. Aerogel can produce the Tyndall effect, mainly because it is porous, when the gas through the aerogel, gas molecules will enter the aerogel at a very low speed, so that the concentration of gas in the aerogel changes, thus affecting the surface tension of the aerogel, resulting in the Tyndall effect.
3. the application of aerogel
Aerogel has special microstructure characteristics such as high specific surface area, high voidage, stable chemical properties, low thermal conductivity, high temperature resistance, wide temperature range and long life. As the currently known solid material with the lowest thermal conductivity and the lowest density, aerogel can be described as the "king of heat insulation" in the field of materials, and has been applied in aerospace, petrochemical and other fields. For example, aerogels have been applied to the engine of the "Tianwen 1" probe and the surface of the rover, the high-temperature gas system of the "Long March 5" remote launch vehicle engine, and the thermal battery protection of the Chang 'e-4 probe. After China put forward the goal of "double carbon", with the continuous innovation of technology, the application scenarios of aerogel are also further expanded.