--- title: "The Electromagnetic Spectrum" description: "Describe the full electromagnetic spectrum from radio waves to gamma rays, in order of increasing frequency and energy; explain that all EM waves travel at the same speed in a vacuum; and describe the" canonical: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-mt_XSp-S0wter source: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-mt_XSp-S0wter.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # The Electromagnetic Spectrum Describe the full electromagnetic spectrum from radio waves to gamma rays, in order of increasing frequency and energy; explain that all EM waves travel at the same speed in a vacuum; and describe the uses and hazards of different regions Subject: Science · Area: Waves, Light & Sound · Ages 12 to 13 Page: https://lightmysky.com/learn/science/the-electromagnetic-spectrum-mt_XSp-S0wter ## Ready when they can - Lists the seven regions of the EM spectrum in order of increasing frequency - States that all EM waves travel at 3 × 10⁸ m/s in a vacuum - Gives at least one use and one hazard for each region of the spectrum - Explains why some EM waves are more dangerous to living tissue than others (linked to frequency/energy) ## Lesson: The Electromagnetic Spectrum Light is only one member of a huge family of waves called the electromagnetic spectrum. Every member of this family travels through empty space at exactly the same speed: 3 x 10^8 metres per second (300,000,000 m/s). What makes each member different is its frequency, how many wave cycles pass a point every second. *(drawing: The seven regions, arranged from lowest frequency (radio) to highest (gamma). Visible light, the tiny slice you can see, sits in the middle.)* **Example.** A microwave oven uses microwaves to shake water molecules in your food and heat it up. A hospital X-ray machine uses X-rays, much higher up the spectrum, to pass through skin and show your bones. Both are electromagnetic waves moving at the same speed. The X-ray just carries far more energy in each wave. Every region has jobs it's good at, and risks that come with it. Radio waves carry TV and phone signals with almost no risk to you. Ultraviolet light from the sun helps your skin make vitamin D, but too much gives you sunburn or skin cancer. Gamma rays can kill cancer cells in radiotherapy, but they can also damage healthy cells if you're overexposed. **Tip.** Higher frequency means higher energy. Radio, microwave, and infrared waves mostly just warm things up gently. Ultraviolet, X-ray, and gamma waves carry enough energy to break bonds inside living cells, which is why doctors and radiographers wear shielding around them. **Recap.** All seven regions of the electromagnetic spectrum travel at the same speed in a vacuum; the higher the frequency, the higher the energy, and the greater the risk to living tissue. ## Practice 20 questions on this page, each with its working shown. ## Needs first - [Wave properties & types](https://lightmysky.com/learn/science/wave-properties-and-types-mt_LxK9OKZQZX) - [Reflection & Refraction](https://lightmysky.com/learn/science/reflection-and-refraction-mt_PifbJOuXrG) ## Opens up - [The Electromagnetic Spectrum: Uses and Dangers](https://lightmysky.com/learn/science/the-electromagnetic-spectrum-uses-and-dangers-mt_P_NXNSo1zQ) - [Observing with Light Waves](https://lightmysky.com/learn/science/observing-with-light-waves-mt_rbY77m8_s1) - [Waves & Different Materials](https://lightmysky.com/learn/science/waves-and-different-materials-mt_w5HzPpOUmj)