Question

across

1. one half of earth
2. it takes earth 365.25 days to do this
3. waves used to kill bacteria
4. waves with the longest wavelengths
5. in the northern hemisphere, the sun’s rays are spread out over a greater area

down

1. at the equator, the sun’s rays are concentrated over a small area
2. the angle at which the sun’s rays reach earth’s surface
3. 12 hours of day and 12 hours of night on september 22 or september 23
4. sun’s energy that enters the atmosphere
5. 12 hours of day and 12 hours of night on march 20 or 21
6. a measurement of incoming solar radiation

Explanation:

This is a geography - related crossword puzzle. Each clue refers to a geographical or astronomical concept related to Earth - Sun interactions, waves, and time periods. For example, "One half of Earth" refers to a hemisphere, "It takes Earth 365.25 days to do this" refers to orbiting the Sun, etc.

Answer:

ACROSS:

1. Hemisphere
2. Orbit the Sun
3. Ultraviolet waves
4. Radio waves
5. During winter (implied as the Sun's rays are spread out more in winter in the Northern Hemisphere)

DOWN:

1. Direct (at the Equator, Sun's rays are more direct)
2. Angle of incidence
3. Autumnal equinox
4. Insolation
5. Vernal equinox
6. Insolation