CK-12 Foundation
Ck 12: Physical Science: Ultrasound
[Free Registration/Login may be required to access all resource tools.] What ultrasound and echolocation are, and how sonar and ultrasonography are used.
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Bats4 Kids: Bats, Bats, Everywhere
Bat Conservation International has 24 biologists, educators, and administrators who are dedicated to their mission to further education, research, and conservation of bats. Dr. Merlin Tuttle and his staff have constructed Bats4Kids to...
