I have found two interesting sites that have live science lessons on a variety of topics.
The first is Let’s Go Live with Maddie & Greg. This pair films five days a week live from their home in the UK. Although the time difference makes it difficult to watch live, the thirty minute episodes are available on Maddie’s YouTube channel, along with the corresponding links to activities and websites that they discuss on their show. Each week they have a theme, beginning with gardens and including: space, makers, dinosaurs, the body and the earth.
The second is Earth Live Lessons Hosted by Liz Daily on her Wildlife TV YouTube channel. These twenty minute episodes are mostly about the earth and wildlife; however, they are led by a variety of scientists, conservationists and filmmakers.
Let me know if you have found any other cool science videos or activities that you think are worth sharing!