Understanding Evolution
The National Science Digital Library

The National Science Digital Library
FREE
Compendium of digital science resources from dozens of academic institutions. Includes resources for Preschool through Adult-level education. Subjects include: Applied Science, Computing and Information, Engineering, Technology, Life Science, Ecology, Mathematics, Physical Science, Chemistry, Geoscience, Physics, and Space. Resource types include: Activities and Labs, Case Studies, Data Sets, Illustrations, Games, Homework and Assignments, Interactives, Lectures, Lessons and Lesson Plans, Primary Sources, Simulations, Student Guides, Textbooks and Unit Studies.
Legends of Learning
ScienceMom
KiwiCo Panda Crate
Material Science Scavenger Hunt

Material Science Scavenger Hunt
$
Full-disclosure, this is a Treasure Hunt Builder scavenger hunt! For early education, the focus is to give students the language to recognize materials around them, and to infer similar properties in those materials. This scavenger hunt categorizes materials into seven groups: metals, ceramics, glass, plastics, wood, textiles, and composites.
MEL Science

MEL Science
$$$
MEL Science is a subscription box which focuses on Chemistry or Physics. This box is excellent because the science principles demonstrated in each box are solid and thorough; this is not a superficial science experiment subscription. The experiments are engaging, and really give children hands-on experience with chemistry and physics concepts.
Starry Night Education

Starry Night Education
FREE Resources Available, Subscription Version $$$
This is a very thorough subscription for anyone interested in a deep dive into Astronomy and Earth Science, but is quite expensive. There are free resources available in the Resource drop-down menu, including Starry Night videos, Interactive Sky Charts, and Starry Night Panoramas.
Smithsonian
NASA

NASA
FREE
There is so much material here. There are also standards-aligned activities with helpful filters by grade level, subject, type of activity, and topic: Aeronautics, Aircraft Probes, Satellites and Spacecraft, Algebra, Arts, Astrobiology, Astronomy, Chemistry, Computer Programming, Computer Science, Data Collection, Analysis and Probability, Earth, Earth and Space Science, Earth Processes, Earth science, Earth, Moon and Sun, Electricity and Magnetism, Energy, Engineering and Technology, Geology, Geometry, Heat and Thermodynamics, Image Processing and Visualization, Inertia, Language Arts, Life Sciences, Light and Optics, Materials Science, Mathematics, Measurement, Motion and Forces, Number and Operations, Number Sense, Performing Arts, Physical Sciences, Problem Solving, Remote Sensing, Satellites and Spacecraft, Size and Scale, Solar System, States of Matter, Structure and Properties of Matter, Teachable Moments, The Design Process, The Nature of Science and Technology, The Scientific Process.