Helen J. Challand

No biography available.

Works (11)

Cover of Plants without seeds

Plants without seeds

Cover of Experiments with magnets

Experiments with magnets

Cover of Disappearing wetlands

Disappearing wetlands

Cover of Science activities from A to Z

Science activities from A to Z

Cover of Activities in the earth sciences

Activities in the earth sciences

Cover of Experiments with chemistry

Experiments with chemistry

Cover of Earthquakes

Cover of Experiments with electricity

Experiments with electricity

Cover of Activities in the physical sciences

Activities in the physical sciences

Cover of Vanishing forests

Vanishing forests

Cover of Activities in the life sciences

Activities in the life sciences