In this experiment, you will investigate the greenhouse effect using a simple model. You places two identical beakers of water on a bench, each containing 2...

(a) The starting temperature shown on thermometer T1 is 22 °C. [1]

(b) The covered beaker reached the higher temperature (34 °C compared to 29 °C for the open beaker). [1]

(c) The glass plate allows short-wavelength visible light from the desk lamp to pass through it and heat the water inside. [1] The warm water then emits longer-wavelength infrared radiation. However, glass is largely opaque to these longer infrared wavelengths, so this radiation cannot escape back through the glass plate. The thermal energy becomes trapped inside the covered beaker, causing its temperature to rise higher than the open beaker where infrared radiation escapes freely. [1]

(d) The glass plate in this experiment acts like greenhouse gases (such as carbon dioxide and methane) in Earth's atmosphere. [1] In the real greenhouse effect, short-wavelength radiation from the Sun passes through the atmosphere and warms the Earth's surface. The warm surface emits longer-wavelength infrared radiation. Greenhouse gases absorb this outgoing infrared radiation and re-emit it in all directions, including back towards the surface. This traps thermal energy in the lower atmosphere, raising the temperature above what it would be without these gases. [1]

(e) One way to ensure a fair test: use the same volume of water (200 cm³) in both beakers. Other valid answers include: both beakers start at the same temperature, both are the same distance from the lamp, both beakers are the same type and size, or both are placed on the same bench in identical conditions. [1]