I would suggest that you develop your own class website. With your website, you can have the assignments for the week, documents you want students to read, links to appropriate websites, and even your own presentations. You can also have individual students use their own page on the website where they can upload projects for grading. This would be an easy way for you to have continuous communication with your class both inside of school and outside of school. The parents will love this, too.
This is the way to go. My first year, I kept a notebook of all the assignments we completed. It wasn't the most efficient way to do things. But a class blog, with a recap of what happened, a link to any notes or powerpoints, and the assignment is a good way to keep students up to date. If they're absent, they learn that the routine is to check the website (and then maybe check with a classmate).
I agree that developing a website is an easy way to let students and/or parents know what they've missed. Another option that I find successful is "Homework Buddies". During the first week of school, each student in my class pairs up with another student (preferably someone that lives near them) to be HW Buddies for the school year. If a student is absent, their HW Buddy collects all their materials for them and keeps a quick summary log of what we did in class and that night's homework assignments. If the student lives near the HW buddy, they can drop off the materials after school. If the student has a sibling in the school, the HW buddy can also find the sibling at the end of the day to give them the materials missed. If the HW buddy can't get to their buddy's house that night, they at least have kept track of what the student has missed while he/she was absent and then can make up the materials during study period or after school. Hope this helps!
No need to worry or be discouraged. You can talk to the students and get them back to the classes.
I agree with Mel - classroom website or blog is really the easiest way to keep all students informed. Also, create your classroom video channel and record lessons.
In addition to the idea of a class website, let me suggest a learning management system like Schoology or Google Classroom. A website lets you list out assignments and share resources, and that's great. But at some point, students don't even know what they haven't turned in. When they can see their grades and see the grade for each assignment, they know if they missed something. Schoology was an amazing tool for me to keep kids up to date, but it helps to have one to one computers or tablets.
You have to explain every topic in science with examples. It will make study interesting and learn a lot from them. You can teach them from animated videos and also create pages of each student on your own class website. They upload projects and assigned work on the class website whenever they free. It is the best way of communication between student and teacher.