Possible 6 markers

Question 1

how did william herschel discover infra-red radiation

Answer 1

used a prism to split light into the colours of the visible spectrum. used a thermometer to investigate the heating effect from each colour. the heating increases from violet to red. he investigated the region beyond red. he found a even bigger heating effect. he found infra red radiation

Question 2

how did johann ritter discover ultraviolet radiation

Answer 2

used a chemical silver chloride, which turn black when light shines on it. silver chloride turns black faster in violet light than it does in red light. it turned black even faster when it was exposed to invisible radiation beyond the violet part of the spectrum. Ritter had discovered ultraviolet radiation.