The U.S. National Resource Council lists five features at the core of teaching through science inquiry:
  • "Learners are engaged by scientifically oriented questions."
  • "Learners give priority to evidence, which allows them to develop and evaluate explanations that address scientifically oriented questions."
  • "Learners formulate explanations from evidence to address scientifically oriented questions."
  • "Learners evaluate their explanations in light of alternative explanations, particularly those reflecting scientific understanding."
  • "Learners communicate and justify their proposed explanations."

This article "The Teacher's Role in an Inquiry Centered Classroom" has ten great tips for teachers wanting to use an inquiry approach. Here are some resources for incorporating Inquiry learning into your science lessons:
CREST, Creativity in Science and Technology is a CSIRO initiative, which provides real-life, open-ended investigation in science and technology. it is a non-competitive program for primary and secondary students which encourages success and the development of skills and processes and allows students to pursue a topic of interest to them.
INTEL aims to inspire the next generation of scientists and engineers by encouraging students' interest in science and maths. They sponsor science competitions which allow teachers and students to develop rich, interactive learning experiences.
The Science Buddies site has hundreds of science fair project ideas and a topic selection wizard to help students choose projects that may interest them. It also has a science fair project guide to assist your students and an "Ask and Expert" page. I set up a wiki for schools from different countries to post their projects as an Online Science Fair. Give students a template and a timeline to assist them to plan and complete their projects.
Open Educational Resources has a range of science by inquiry resources for primary and secondary classes. Includes topics such as the Life Cycle of Stars, Magnetic Field Activities and Marine Bioluminescence.
Hands-on Activities for teaching Biology to high and middle school students has an excellent range of activities from basic diffusion and osmosis to DNA and Natural Selection. Includes student handouts and teacher preparation notes.
Inquiry in Action has some excellent activities to promote inquiry learning in chemistry and physics for junior and middle school. Water, states of matter and chemical change are some of the topics with activities listed.