Problem is, in my library at least, the bulk of the books in the science experiments area were geared towards upper elementary, science fair type projects. Not only are many of the concepts going to be beyond 3-6 year olds, but the skills required to design, implement, and analyze the results are beyond the scope of developmentally appropriate practice for most in that age range.
So I set out on a mission to request as many books as I could that seemed, from their catalog records at least, to be appropriate for a 3-7 year old audience.
For librarians, these 9 books/series I'd recommend as general purchases for your library or system.
Kitchen Science Lab for Kids: 52 Family-Friendly Experiments from Around the House by Liz Heinecke
Written by a Minnesota mom and author of the popular Kitchen Pantry Scientist site, this book emerged from her experience searching for experiments that would be safe enough for her youngest, engaging enough for her oldest, and completed with items already found around the house. That's a tall order! Heinecke's suggestion of a science journal will integrate easily into homeschool study, and the color photographs and clear writing make following the experiments easy.
The Curious Kid's Science Book: 100+ Creative Hands-On Activities for Ages 4-8 by Asia Citro
"[Science is] about asking your own questions and making your own investigations--two things young children are very good at!" says Citro. She goes on to say, "Babies and toddlers learn about their world by forming questions and experimenting to find the answers...Young children are curious, observant, and determined problem solvers." Therefore, this book doesn't offer prescribed, step-by-step experiments. This book will engage children (and their adults) in critical thinking skills at every step of the scientific process. Because of the format, this book will offer science experiences that provide rich, flexible, and easily differentiated learning. I see a natural progression from Kitchen Science Lab for Kids to The Curious Kid's Science Book for homeschooling families or families with serious STEAMy interests.
The Kid's Book of Simple Everyday Science by Kelly Doudna
40 simple experiments covering physics, chemistry, and biology are presented in easy to follow directions with colorful photographs. Pictographs indicate which experiments require safety glasses, adult help, heat, or sharp objects. A great collection for general home use.
More Super Simple Science series, ABDO publishing
Experiments are presented with simple instructions and large color photos, along with a differentiated version of the scientific method suitable for young children. Titles in the series include: Light, Food, Gravity & Motion, Liquid, Magnets, and Sight & Sound.
First Science Library series, Armadillo (Anness Publishing)
Each titles includes many simple experiments that require mostly household items and very little time. Pages at the back offer "hints for helpers," with more detailed information about what is happening in each experiment. Books are published in the UK, so some conversions will need to be made. Titles in the series include: Water Play, Magnets & Sparks, Light & Dark, Sound Magic, On the Move, Animals & Plants, and Up in the Air
Janice VanCleave's Big Book of Play and Find Out Science Projects by Janice VanCleave
Inspired by questions asked by real kids, the book offers science activities that involve playful, hands-on experiences designed for use for 4-7 year olds. The book includes section summaries, a glossary, and a teacher's guide to preparing and presenting the lessons, A good supplement for development science process skills, curiosity about scientific concepts, and exploration, but not a good fit for families wanting step-by-step experiments following the scientific method.
Science Play! by Jill Frankel Hauser
Subtitled "Beginning Discoveries for 2- to 6-year olds," this boo has been the recipient of the American Institute of Physics Science Writing Award, Early Childhood News Directors' Award, and the Parents' Choice Approved Award. The book's introductory material stressed the role of scientist for the child and lab assistant for the caregiver, a scientific methods for little learners, as well as a shopping list for common items used in the discoveries featured in the book. Best suited for informal learning than fulfilling specific standards or objectives.
Whiz Kid Science series, Raintree (Capstone Publishing)
Rather than separating the background and explanatory science information from the experiments as I observed in many of the other books, all the relevant info for each experiment is presented together. A bonus "Troubleshooter!" tip box offers suggestions on how to adjust or change the expeirement of environment in order to achieve success. In terms of preschool appropriate, step-by-step experiments, this series offered the presentation I preferred the most. Titles in the series include: Make it Boom!, Make it Zoom!, Make it Glow!, Make it Change!, Make it Grow!, and Make it Splash!
BONUS: Science Around Us series, The Child's World
The titles in this series would pair well with experiments illustrating the concepts presented in the books. Using illustrations and photography, the books simplify concepts to a more understandable level for young learners. Back matter provides suggestions to parents and caregivers of more resources to consult for those looking for more in-depth study. Titles in the series include: Air, Dirt, Electricity, Energy, Magnets, Shadows, Sound, and Water.
Additional books and series:
For librarians looking to expand their collections, I'd consider these supplementary purchases for this age group.
Junior Scientists series, Cherry Lake Publishing
Lightning Bolt Books: Plant Experiments series, Lerner Publishing Group
The Giant Science Encyclopedia of Science Activities for Children 3-6 edited by Kathy Charner
150 Amazing Science Experiments by Chis Oxlade
Everyday Science Experiments series, Windmill Books (Rosen Publishing)
First Facts Fun Science series, Capstone Publishing
I'm a Scientist: In the Kitchen by Lisa Burke
Science Explorer Junior series, Cherry Lake Publishing
Six-Minute Nature Experiments by Faith Hickman Brynie
Six-Minute Science Experiments by Faith Hickman Brynie
Show-Me-How: I Can Experiment by Steve and Jane Parker
Future Releases to Watch for:
I can't guarantee these will be suitable for preschool aged science experimentation. But they've caught my eye so far, and I'll look for reviews closer to their publication dates.
A Little Bit of Dirt: 55+ Science and Art Activities to Reconnect Children with Nature by Asia Citro
My First Book of Science Experiments by Thomas Canavan
Outdoor Science Lab for Kids: 52 Family Friendly Experiments for the Yard, Garden, Playground, and Park by Liz Heinecke
Whatever the Weather: Science Activities and Art Activities that Explore the Wonders of Weather by Annie Riechmann
Amazing (Mostly) Edible Science: a Family Guide to Fun Experiments in the Kitchen by Andrew Schloss
Show Me How I Can Do Science by Steve and Jane Parker
FUN-damental Experiments series, Bearport Publishing (new titles: Heat, Plants, and Weather)
One-Stop Science series, Smart Apple Media