Listening for Whales approaching_P02

The blue whale is three times as long as our boat! It takes a breath at the surface and sinks below. I ask the captain about whales. He tells me that whales have a lot in common with us. They are mammals. They have live young. Like humans, they care for their babies as they grow. Whales also talk to each other!

They don’t actually say words. They “talk” to each other with sound. To our ears, it sounds like singing. Scientists actually call it whale song. Other whales can hear these songs thousands of miles away. This is very important for whales. They live in very large oceans. Imagine being able to yell loud enough to be heard in another state! How can whales do this? It is because water transmits sounds much better than air.

I’m surprised. I had no idea that sound could travel so well in water. I always talk to people through air. They can always hear me. The captain says sound does travel through air. It just travels better in water.

The captain takes my family below the deck. He shows us a special room. There is a dashboard panel full of instruments in here. They help the captain steer the boat. They also measure weather. He points out one instrument called SONAR.

SONAR lets the captain see what is underwater. It sends out a sound signal under the boat. These sound waves bounce off objects under the boat and make echoes. It then records the echoes that come back. It forms an image on a screen. You can see hills that the boat could run into. SONAR also bounces off big living organisms. It can tell the captain if there are whales nearby.