Below are links that you can go to practice, learn and study for the SOLs.
SCIENCE WEBSITES
Soil
http://web.dps.k12.va.us/ParkAve/soil.htm
http://www.iq.poquoson.org/3sci/soil/3soil04tlm.htm
Water Cycle
http://web.dps.k12.va.us/ParkAve/water.htm
http://marg.mhost.com/Grade3/Watercycle.htm
Solids, Liquids and Gases
http://www.harcourtschool.com/activity/states_of_matter/
http://web.dps.k12.va.us/ParkAve/mattert.htm
Simple Machines
http://web.dps.k12.va.us/ParkAve/simple.htm
Changing Earth
http://marg.mhost.com/mugifs/Grade3/changearth.htm
Living Systems
http://www.hhmi.org/coolscience/forkids/
http://www.saburchill.com/questions/lanlt001.html
http://www.webrangers.us/activities/swimhome/?id=28
http://web.dps.k12.va.us/ParkAve/aniquiz.htm
Moon, Sun and Earth
http://www.bbc.co.uk/schools/scienceclips/ages/9_10/earth_sun_moon.shtml