The ability of heat from the Sun to pass through transparent objects like glass while being blocked by opaque objects is due to the interaction of light with matter.
Light, including heat radiation from the Sun, is made up of electromagnetic waves. When light interacts with matter, several processes can occur: absorption, transmission, and reflection. The behavior of light depends on the nature of the material it encounters.
In the case of transparent objects like glass, the structure of the material allows light to pass through relatively unimpeded. Glass is made up of molecules arranged in a regular pattern, and these molecules do not strongly interact with the incoming light. Instead, the electromagnetic waves of the light pass between the molecules, with minimal absorption or scattering, resulting in the transmission of light.
Opaque objects, on the other hand, do not allow light to pass through because the structure of the material is such that it either absorbs or scatters the incoming light. Opaque materials have a disordered arrangement of atoms or molecules, which causes the light waves to interact with the material in a way that leads to absorption and scattering. The absorbed light is converted into heat energy within the material, contributing to its warming, while the scattered light bounces off in different directions, preventing it from passing through.
In summary, the ability of heat from the Sun to pass through transparent objects like glass is due to the material's structure, which allows light to transmit relatively unimpeded. In opaque objects, the structure of the material causes absorption and scattering of light, preventing its transmission and leading to the object's opacity.