This was a cute slideshow on "Sink or Float" dealing with the science of Matter, although lacked a few basic elements to make it more effective. The lesson needed lots more images. Since this is a 1st grade lesson, students need that visual stimulous to learn more effectively. All of the arrows should be placed at the bottom of the screen. Some of the language is above a 1st grade level, and a little more clarification of what the letters "SWBAT" stood for would have been nice. I was confused as to where to click for the "terms to know" section. I think for this lesson you need to say, "click on "solid" to find out more about it., etc. I did like the YouTube video. It was age appropriate and fun to watch. The quiz was alright, but I think I would place more pics on these two pages also. The content of the lesson was interesting and science related.
You should have "back buttons" on all pages and a "back button" should replace the pic of the "home" icon. For the page with the YouTube video, most kids would click in the middle of the image on the page, but if you do that nothing happens. The link only works if you click on the outer area of the box.