Each unit is a combination of videos, photographs, hands-on activities, and other resources. Probably the first thing you will notice is that they are not grade specific. Instead, the information is layered to let you tailor your study to your interest level. For most units, you could breeze through in a day or two and get the basic information, or you could settle in for weeks of exploration to get a deeper understanding of the science. I open some units before they are complete, and even the "complete" units will grow as I travel to new places, make new videos, take new photos, or develop new resources.
As you go through each unit, if you find yourself wishing for more information, a clearer explanation, or an answer that is not included, email me at: firstname.lastname@example.org
I am always looking for ways to improve this site, making it more useful for students, teachers, and of course, for you. I welcome suggestions for changes, additions, and future units.