Press leaves that are collected on a nature walk or studied in the classroom to demonstrate differences in leaf types or to classify different kinds of leaves. To press leaves, place the leaves in between the sheets of a heavy hardbound book. Leave the leaves there for at least a week, then glue them into the science scrapbook.
When studying simple machines in physics, you can cut out pictures of simple machines such as levers, pulleys, wedges and incline planes. Glue the cut-outs onto the pages of the science scrapbook, along with a short explanation under each image of how the simple machine works.
When studying chemistry, you can use pH strips to test the different pH levels in foods, fluids or any other substances. Test a wide range of substances that will yield results reflecting both acids and bases. Organize the strips into results that read as acid or base, then glue the strips onto a sheet in your science scrapbook.