
A laser is a thin beam of light. People use lasers all the time. You may have a laser at home. A DVD player uses a laser to read a DVD. A cashier uses a laser to read bar codes.
Photo Credit: ktsdesign/Shutterstock
April 22 is Earth Day. Let’s look at ways we … read more
There are many amazing places in the world. Let’s look … read more
May 8th is World Red Cross Day. Let’s look at … read more
© 2025 McGraw-Hill Education. All Rights Reserved.