
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
This is Emmett Chappelle. He was a famous scientist. He … read more
The Sun gives off both light and heat. We can … read more
Big and small, spider webs are everywhere. Spiders weave webs … read more
© 2026 McGraw-Hill Education. All Rights Reserved.