thermal expansion
thermal expantion
thermal expantion
Dangerd
Yes, it should be. If the sidewalk is not higher than the lawn water will collect on top of the sidewalk when it rains. If the temperature drops below freezing the sidewalk could crack.
spitting on the sidewalk
It depends on the size of the sections, but generally, no less than 4 inches.
The sidewalk being warmed by the heat of the sun is a physical process. The sun's rays transfer heat energy to the sidewalk through radiation, causing the molecules in the sidewalk to vibrate more rapidly and increase in temperature. This is a physical change as no new substances are being formed in this process.
sand applied to a slick sidewalk
When direct sunlight heats the sidewalk, the concrete absorbs the sun's energy. This energy increases the temperature of the sidewalk by causing its particles to vibrate more rapidly, resulting in the sidewalk feeling hot to touch.
As you walk barefoot on a hot sidewalk, the sidewalk molecules vibrate more due to the heat, transferring thermal energy to your feet. The heat is moving from the sidewalk (higher temperature) to your feet (lower temperature), causing your feet to feel hot. The increased molecular vibrations in the sidewalk result in the sensation of heat on your feet as thermal energy is transferred.
The answer will depend on what material the sidewalk is made from and the maximum range in temperature.
When direct sunlight heats the sidewalk, the concrete material of the sidewalk absorbs the heat energy and warms up. This causes the molecules within the concrete to move faster, increasing the overall temperature of the sidewalk. The sidewalk then radiates this heat back into the environment, contributing to urban heat island effect.