RADIOACTIVITY

The atoms of some chemical elements are unstable. They try to rearrange themselves to make more stable atoms. In the process, they give off radiation particles or tiny bursts of radiation. This process is called radioactivity. Although radioactivity can be harmful to people, it can also be important to us in everyday life. It is used to make nuclear energy and preserve food, and it also plays a vital role in the treatment of cancer.

DANGER: RADIATION

Some types of radioactivity are harmful, because they damage or destroy the tissues of the human body. If people receive large doses of radioactivity, they can become ill with radiation sickness, which often causes cancer. Radiation sickness can also affect people’s ability to have children.

TYPES OF RADIOACTIVITY

The three types of radiation are alpha and beta particles, and gamma radiation, named after the Greek letters above. An alpha particle is two protons joined to two neutrons. A beta particle is an electron. Gamma radiation is high-energy electromagnetic radiation.

ALPHA DECAY

An alpha particle is made when the nucleus (central part) of a large, unstable atom rearranges itself, or decays, to make a smaller, more stable atom. The new and smaller atom has two protons and two neutrons fewer than the original atom. These join together to make the alpha particle that is given off. Some energy is also released as a gamma ray. This is high-energy and high-frequency radiation, travelling at the speed of light.

BETA DECAY

Beta decay is quite different from alpha decay. One of the neutrons in the nucleus of the unstable atom changes into a proton and an electron. The proton joins onto the nucleus, but the electron is ejected from the atom at high speed. This fast-moving electron is called a beta particle. Some energy is also released as a gamma ray.

RADIOTHERAPY

Radioactivity can cause cancer if it harms healthy cells in the human body. It can also help to cure cancer if it is used to destroy unhealthy cells. In radiotherapy, a powerful machine fires carefully targeted beams of radiation at tumours (cancer cells) in the patient’s body. The radioactivity destroys the cells and helps to improve the patient’s chances of survival.

Copyright © 2007 Dorling Kindersley

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Twitter icon Follow Us on Pinterest

editor’s picks

highlights

Printable Fall Fun To-Do List
Celebrate the cooler weather with this printable checklist of fun fall activities for your whole family.

Kindergarten Readiness App Wins Gold
Our Kindergarten Readiness app won the Gold Award of Excellence in the educational category at the 2014 Communicator Awards. This valuable checklist comes with games and activities to help your child practice the essential skills she needs for kindergarten. Download the Kindergarten Readiness app today!

Top 10 Care Package Items for College Students
Show your college student that you love and miss her by mailing a care package full of dorm room essentials and comforting treats. Whether it's her birthday, exam time, or just because, get care package ideas to brighten her day.

Find Today's Newest & Best Children's Books!
Looking for newly released books for your child? Try our new Book Finder tool to search for new books by age, type, and theme, and create reading lists for kids!