Science Simulations for 4th Grade

I am working with my students on 4th grade interactive science notebooks and I was looking for some online resources for science.  I love this list of simulations

<div style="position: relative; width: 300px; height: 200px;"><a href="https://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom_en.html" style="text-decoration: none;"><img src="http://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom-600.png" alt="Build an Atom" style="border: none;" width="300" height="200"/><div style="position: absolute; width: 200px; height: 80px; left: 50px; top: 60px; background-color: #FFF; opacity: 0.6; filter: alpha(opacity = 60);"></div><table style="position: absolute; width: 200px; height: 80px; left: 50px; top: 60px;"><tr><td style="text-align: center; color: #000; font-size: 24px; font-family: Arial,sans-serif;">Click to Run</td></tr></table></a></div>