3.2.1 Know that light is part of a continuous electromagnetic spectrum that includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations, and that all these waves travel at the same speed in free space
3.2.2 Know the order of the electromagnetic spectrum in terms of decreasing wavelength and increasing frequency, including the colours of the visible spectrum
3.2.3 Explain some of the uses of electromagnetic radiations, including:
radio waves: broadcasting and communications
microwaves: cooking and satellite transmissions
infrared: heaters and night vision equipment
visible light: optical fibres and photography
ultraviolet: fluorescent lamps
x-rays: observing the internal structure of objects and materials, including for medical applications
gamma rays: sterilising food and medical equipment
3.2.4 Explain the detrimental effects of excessive exposure of the human body to electromagnetic waves, including:
microwaves: internal heating of body tissue
infrared: skin burns
ultraviolet: damage to surface cells and blindness
gamma rays: cancer, mutation
and describe simple protective measures against the risks
