Silica aerogel particles were tested to see how pressure affects their ability to insulate against heat. The researchers used a special setup with a heat source and measured the thermal conductivity of the particles at different pressures. They found that as the pressure decreased, the thermal conductivity of the aerogel particles also decreased. This means that under lower pressure, the particles were better at insulating against heat. This suggests that crushed silica aerogel particles could be a cost-effective alternative to traditional insulation materials.