Arctic Series - Narwhals - STEM Challenge
Narwhals are very chatty marine mammals that communicate with buzzes, whistles and clicks through echolocation. They also use sound to locate prey and navigate their way underwater. For Narwhals, sound is a very important survival skill. With shipping and commercial activity increasing in our oceans, Narwhal communication is at risk. Learn more about how sound travels underwater with our Narwhal STEM activity.
Listen to Sounds Travel Underwater
Sound travels well through air, but it travels even better through water! This simple sound activity can be done in a jiffy out on the back porch, in a classroom or at the kitchen table.
Supplies Needed:
A bucket filled with water
A large plastic water or soda bottle
At least 2 butter knives
Scissors or sharp knife to cut the bottle
A partner
What to Do:
1. Fill your bucket with water, then take a sharp knife or scissors (with the help of an adult) and cut off the bottom of a plastic water bottle. Be sure to take the cap off the bottle.
2. Place the bottle in the water so that the cut bottom is submerged. Then place your ear to the top of the bottle to listen.
3. Using the butter knives, clang them together to make a sound in the bucket while your partner is listening. What do they hear?
4. Next remove your ear from the bottle and try the same thing with the knives outside of the water. What do you hear? Is there a difference?
Discuss the results. Sounds travel faster through denser materials than through less dense materials because the molecules in denser materials are closer together causing more vibrational energy to be transmitted. Water is denser than air. Therefore, sound travels about five times faster through water than through air. Animals that live underwater are able to hear sound clearly.
See the Sound
Sound vibrations travel through air, water, and even solid objects, but it’s not possible to see the waves. What if we could see the waves in another way? This science of sound experiment makes sound more visible by forcing objects to react to the sound vibrations.
Supplies Needed:
Empty clear mixing bowl
Plastic wrap
Large rubber band
Sugar crystals- Sugar in the Raw works great, or make sugar crystals in another science experiment! Tiny beads would also work well.
What to Do:
1. Wrap a sheet of plastic wrap over the mixing bowl so that it’s tight, and secure with the large rubber band (just like a drum).
2. Sprinkle a few of the sugar crystals on the top of the plastic wrap.
3. Now get close to the sugar crystal and say something loudly! What happens to the crystals? Do they move?
4. Experiment with louder and softer words, sounds or sentences to watch the sugar crystals react to the sound vibrations!
While you might think it’s your breath making the crystals jump and move, it’s actually the sound vibrations! Try different sounds besides ordinary speech and see how the crystals come to life!
We suggest using some real Narwhal sounds. You can find some here.
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