GeoGebra has over 1 MILLION free activities, simulations, exercises, lessons, and games for math & science! Each is designed to be an interactive demonstration of a mathematic or scientific principle. Teachers can browse through the resources and share them with students via a link or a join code.
From their Teacher Handbook: “NextGen Science Storylines are instructional units developed by the NextGen Science Storylines Project at Northwestern University. These units reflect the storyline approach from Reiser, Novak, and McGill (2017), in which the questions and problems students identify drive the sensemaking of the unit. The NextGen Science Storyline units are open-educational resources and may be freely downloaded and adapted for local contexts.”
PhET is a website with engaging, interactive math and science simulations. The simulations are written in HTML5, and can be run online or downloaded to your computer. There are over 150 simulations focusing on Physics, Biology, Math, and more. Search by subject, grade level, or accessibility options. The website also includes several teacher guides that provide helpful tips for teaching with PhET
“howtosmile spotlights hands-on and interactive activities, both physical and virtual, that involve doing and learning. Activities take many forms, from downloadable lesson plans to how-to videos to online interactive games. howtosmile activities teach science, technology, engineering and math (STEM) and are developed by a wide range of organizations working with diverse audiences”