David A Adler

Kids use simple machines every day without realizing it. Teeth are wedges and so are knives, forks, and thumbtacks. Many toys such as slides, which are inclined planes, and seesaws, which are levers, are also simple machines. Two appealing kids and their comical cat introduce levers, wheels, pulleys, inclined planes, and more, and explain how they work. This lively introduction to physics will get kids excited about how simple machines simplify our...

Traces the life of the young Jewish girl whose diary chronicles the years she and her family hid from the Nazis in an Amsterdam attic.

It can be surprising which objects float and which don't. An apple floats, but a ball of aluminum foil does not. If that same ball of foil is shaped into a boat, it floats! Why? And how is it possible that a huge ship made of steel can float? Answering these questions about density and flotation is David A. Adler's clear, concise text, paired with Anna Raff's delightful illustrations. Activities that demonstrate the properties of flotation are included....

On Green Day, Cam and her classmates discuss ways to protect the environment, but when money collected for the school's new skylights disappears, Cam uses her photographic memory to solve the mystery.

Cam uses her photographic memory to catch a thief disguised as a ghost.

Cam Jansen battles a famous children's mystery writer to see who can solve the case of the stolen car.

While visiting Aunt Molly at a fancy downtown hotel, Cam uses her photographic memory to help one of the guests find her stolen luggage and pet cat, and to catch the thief.

When Cam Jansen and her friend Eric uncover a mystery while selling fudge door-to-door to raise money for the local library, Cam uses her photographic memory to foil a crime.

Cam and her friend Eric chase the thief of Aunt Katie's wallet through an amusement park and find themselves involved in another case requiring their special detective skills.

When Cam's grandparents are robbed on their way to her parents' surprise birthday party, Cam uses her photographic memory to solve the mystery.