Experiments with Electricity Paperback Helen J. Challand

Experiments With Magnets (New True Books) by Helen Challand

101 Cool Science Experiments by Helen Chapman with Glen Singleton Paperback

Experiments with Magnets Paperback Helen J. Challand

Experiments With Chemistry (New True Books) by Helen J. Challand

Science Projects and Activities by Helen J. Challand (1985, Hardcover)

Experiments With Chemistry (New True Books) by Helen J. Challand