Curious Kids

How do frogs make noise?

Usually, the frogs we hear are male. Male frogs have a special body part called a vocal sac, which is a flexible membrane just under and open to the mouth. To make sound, a frog must close both its nostrils and its mouth. It then squeezes air from its lungs, which passes by the larynx (just like our voice box) before going into the vocal sac. The vibrations caused by the air passing the larynx make sound, which then resonates within the vocal sac. Amazing, isn’t it, that something so small can produce such a loud sound?



Why don’t I have a straw on my face like a butterfly?

How cool would it be to have your own personal face straw that you could curl up and take with you? Butterflies and moths have a proboscis because their food is usually a fluid, for example nectar or plant sap. Insects in the order Lepidoptera (including moths and butterflies) have special muscles in their heads that help them suck up their favorite foods through the proboscis. Humans, on the other hand, need to eat solid foods, so teeth (attached to jaws) are much more useful.

What is your favorite food? If you could design something to help you eat that favorite food, what would it look like and where would it be attached to your body?




How does a flounder’s eye move from one side of its body to the other?

Some of the most amazing things happen in nature! How cool (and weird) is the process of metamorphosis—when an animal’s body changes shape as the animal grows? One of the neatest examples of metamorphosis is eye placement in flatfish such as flounder. When a flounder is young, its body looks a lot like other fish: an upright body and an eye on each side. However, as a flounder grows older, its body changes….a lot! It changes to swimming flat on the ocean floor (it can hide itself this way) and both eyes are on the top of its body.

So how does the eye move from one side of the body to the other? Scientists have evidence that the eye is PUSHED to the other side! How, you ask? By growing bones and muscles on the side that is OPPOSITE to where the eye is moving. To imagine this, you can do a little exercise. Place both arms on a table with your elbows bent and with two fists pushing into each other. Now, keeping your left elbow in the same place, slowly open your left hand, pushing against your right fist. What happens to your right fist? It moves to the right! This is just like an eyeball moving across a flounder’s body, with growing bone and muscle as the left hand. Pretty cool, huh?

Here’s a great time lapse video of a flounder’s moving eye:



Why is fall “Fall” in the northern hemisphere and “Spring” in the southern hemisphere?

The “axis” of the Earth is an imaginary line that passes from the north pole through to the south pole. If one looks at the orbit (path) of the Earth around the sun, the axis of the Earth is slightly tilted. What that means is that, for almost all of the year, EITHER the north pole OR the south pole will be tipped a little bit more toward the sun than the other pole. When the north pole is tipped slightly closer to the sun, then the northern hemisphere has summer! When it is tipped slightly away from the sun, then the northern hemisphere has winter! It is hard to imagine that what we see as a “small tilt” can really affect our weather, but that tilt has a huge impact on the amount of energy in our sunlight.

Check out this video made by MIT students that gives a great explanation for the seasons:



Why can’t people hear echolocating bats?

When we “hear” something our ears are detecting sound waves and sending a signal to our brain.  Sound waves come in different frequencies, some are high and some low. The human ear can detect frequencies up to 16 KHz, while bat clicks are in the range of 40 KHz. How can bat ears detect such high frequencies? Because of a special anatomical part in their ears called a tragus.  Check out this fun video from It’s OK To Be Smart to learn more cool facts about bats.



How do some animals use magnetic fields to migrate?

The Earth is a giant magnet but we don’t usually think about it since magnetic fields are invisible. While we can’t see magnetic fields the way we can see the sun and stars, some animals have specialized body parts that allow them to detect these fields and then use them to migrate. Check out this video that describes a few of the neat features some animals have. Whether it be small amounts of ferromagnetic metals in their cells, to specialized molecules in their eyes, we still have so much to learn about animals!