Scientific curiosity is what’s lurking behind all those questions our kids start asking as toddlers. While we parents don’t always have all the answers, fortunately there’s a ton of cool science apps out there to help indulge that curiosity and spark interest in learning more. So that’s just what we’ve tracked down for you in this next installment of our 2014 Back to School Tech Guide.  We scoured the web for the most stimulating science apps out there, for iOS, Android, and even a few for Windows Phones and Nook–and these are the top 16 we really love. Erlenmeyer flasks not included.

What’s so wonderful about science, when it’s presented in the right way, is that it can be super interesting, filled with cool trivia and neat experiments that help kids learn concepts without even realizing it. These should help for sure.

Best Science Apps for Preschoolers

Heavy or Light app
Science for preschoolers? Absolutely. Science starts with observation, prediction, and comparison, so this app is a great introduction to scientific concepts. Kids can observe, predict, and compare the weight of individual objects and combinations of objects, and gain number sense too. (Available on iTunes for $1.99 and on Google Play for $0.99)

Seasons and Weather app
Another early science concept that’s a good fit for preschoolers is the changing seasons and weather. This science app helps kids make observations about the weather and the time of year, and then draw conclusions about what they should wear and what activities they can do. (Available on iTunes, Google Play, and the Amazon Appstore for free, and for NOOK for $2.99)

Max and Ruby: Science! app
Pretty much every episode of Max and Ruby has a scientific bent if you think about it, with Max doing silly stuff to find out what will happen. In this app, the bunnies learn about the properties of liquids and motion of objects, and of course hilarity ensues, along with some basic physics. Which tends to be easily digested in the hands of beloved TV characters.  (Available on iTunes for free)

Best Science Apps for Early Elementary

Inside Your Outside app
We adore Dr. Seuss, so no surprise that this interactive ebook narrated by the Cat in the Hat is a big hit. The human body and its functions are set to rhyme, alongside diagrams of the eye, the skeleton, blood cells, and more. Kids can explore just how everything works, inside their outsides. (Available on iTunes for $4.99)

DIY Nano + DIY Sun Science apps
The Lawrence Hall of Science at UC Berkeley has a fantastic kids’ science website, along with two cool free apps: DIY Nano and DIY Sun Science. DIY Nano explores the world of atoms and molecules (nano is the prefix indicating 10^-9, get it?), and DIY Sun Science is all about the sun and how it relates to the Earth and our moon. Both apps offer lots of cool experiments and games, some of which require adult supervision. And the willingness to clean up afterwards. (DIY Nano and DIY Sun Science available on iTunes for free; more activities on the Lawrence Hall of Science site)

Plants by TinyBop
Not only is the Plants app full of beautiful illustrations and subtle, natural sounds, it’s a lovely way to appreciate and learn about the natural world in three different biomes, with a fourth coming soon; Tinybop just launched the newest biome, the temperate grasslands So if you haven’t yet snatched up this app which we’ve recommended earlier this year, now’s a great time to do it. (Available on iTunes for $1.99)

Gross Science app
This app is for all the kids who give the side-eye to science, because even the most cynical kid can’t resist whipping up a batch of snot, growing mold, or recreating the scent of stinky feet. Gross Science is full of icky info and activities that are truly grody to the max (or whatever the kids say these days), which should create some new science fans for life  (Available on iTunes and Google Play for $2.99)

Best Science Apps for Later Elementary

Monster Physics
From the developer who created Cool Mom Tech fave apps Stack the States, Presidents v. Aliens, and Mathmateer comes yet another winning app for kids. In Monster Physics, kids can use dozens of parts, made from different materials like wood and rubber and ice, to build contraptions that are used to solve missions. There’s no single right answer to any problem, so kids get to use their creativity, completing missions multiple times using different solutions to see what happens. (Available on iTunes for $0.99)

Meet Science: Magnetism and Electricity
This app is one of the pricier ones on our list, but to me it’s well worth it to help kids gain an early understanding of these two super challenging physics topics. With animated discussion, experiments captured on video, mini games to help apply knowledge, and an extensive glossary that includes simple definitions and diagrams, I’d even recommend this app as a supplement to high school physics. I have a touch of PTSD where it comes to physics myself, and I imagine this would have been a huge help to me when I was a kid.  (Available on iTunes for $6.99)

Sound Uncovered + Color Uncovered
San Francisco’s Exploratorium website not only offers tons of activities and videos on topics ranging from food science to space and astronomy, they’ve also launched two amazing ebooks. Sound Uncovered deals with the idiosyncrasies of sound, music, and language, while Color Uncovered looks at sight and the visual spectrum as experienced by humans and animals. Bonus: Click on the Candy-o-Matic. If your kids are like mine, they’ll giggle and ask to listen over and over again. (Sound Uncovered and Color Uncovered available on iTunes for free)

My Incredible Body
We’re still impressed by the medically accurate models and high level of detail in this app, along with the ability to view multiple anatomical systems at the same time. What’s new here is that the reproductive system is now available as an in-app purchase for $1.99. For kids beginning to study anatomy and physiology — and those mature enough to take a clinical view of organs and their function (which may leave out even some high schoolers, we realize) — My Incredible Body can be a valuable supplement to dry textbook coverage. (Available on iTunes and the Windows App Store for $4.99 and on Google Play  for free for Android)

Best Science Apps for Middle School and High School

Powers of Minus Ten: Cells and Genetics
With a nod to Charles and Ray Eames’ Powers of Ten documentary, this app offers a stunning view of cells, molecules, and proteins, along with processes like cell division and DNA replication. I especially love how you can zoom in and out to gain a greater appreciation of relative size — say, between a skin cell, the cytoplasm within that skin cell, and the DNA that makes up the chromosomes within that skin cell. Completely mind-boggling and utterly captivating. (Available on iTunes and Google Play for $1.99)

Chem Lab
By no means is this app fancy or visually stimulating (as you can tell), but your kid needs help learning and remembering which elements comprise different chemical compounds, this app definitely gets the job done. Plus it’s entertaining: If you get the answer wrong, the flask blows up and lab tech sports a bandage. (Available on iTunes for $0.99)

Solve the Outbreak
With the recent international news concerning Ebola, this app is sure to be a popular one. Created by the Centers for Disease Control, Solve the Outbreak lets the user be a disease detective, taking steps to contain an outbreak. It could inspire interest in public health issues–and definitely help kids to feel more empowered and educated when it comes to alarming and inescapable health stories in the news. (Available on iTunes and Google Play for free)

More from our 2014 Back to School Tech Guide 
– 10 of the best organizational apps for parents
– 16 best math apps for kids of all ages
– 12 of the best educational apps for preschoolers
– 11 of the Best reading apps for kids