Can infra-red light penetrate through aluminium foil?

Answer 1

Penetration depth will be very low and so for practical purposes, the infra red will not travel through the Aluminum foil.

A large fraction of the infra red radiation hitting the aluminum foil will be reflected. The rest will be absorbed by the foil. The infrared absorbed will heat up the aluminium foil allowing some infra red to be emitted from its surface in turn.

Often people think of infrared as being heat, but in fact the warming/heating one feels when skin is exposed to infrared, is the energy of the infrared waves raising the temperature of the skin.

The wavelength of infrared is such that the penetration depth in aluminium foil is limited, so the foil would have to be a few atom layers thick before it would actually go right through.

Infra red has only a slightly longer wavelength to visible red light, so a slight variation on the question is - can light shine through a piece of aluminum foil. The same answer applies.

X-rays and gamma rays will have a much higher depth of penetration.

Answer 2

yes of course

infra-red is heat and heat goes through aluminium foil