run this by him
If you’re stuck in the rain, taking a bath, or swimming in the ocean, you’re going to feel really wet! But why??
Wetness is just a feeling. It’s something that our brains tell us about what we’re touching, and water has some pretty special qualities that make it feel wet when we touch it.
If we put our hands in water, we feel the water swirl around our fingers and our palms. We feel the pressure of the water. Imagine someone squeezes your hand or gives you a strong handshake. That squeeze is pressure on our hands, but it doesn’t feel wet. Water gives our hands a very light squeeze, with just a little pressure that changes as our hands move through it.
Imagine putting your hand into some sand. You probably have to force the sand out of your way, maybe wiggling your fingers or digging a hole. It’s not easy, like it is with water that just changes shape to let your hand travel through it. When you take your hand out of the sand, the sand doesn’t go back to its original shape, but water does! The way it moves around our hands is another quality of water that makes us feel wetness.
Most of the time water also feels cool. It has a cooling effect on our skin. At times it can also be warm. The difference in temperature from the air helps our brain realize that the water isn’t air and that we feel wet.
It is a combination of temperature, pressure and the way it moves tells our brains that water is wet. Our brains are able to take all this information and figure out what we’re feeling right away! It’s pretty amazing!
Just a Phase!
Above, we talked about water as a liquid—a wet substance like juice or milk, but it also comes in different forms. These different forms are called “phases.”
Water can sometimes be hard and solid when it is very cold. Then, you most likely know it as ice or snow! It can be a gas too, like steam, when it gets very hot! Most of the time though, water is in its liquid form, and that is very wet.
A Tense Situation!
Water also likes to stick to itself—not so much that we can’t run our hands through it, but just enough that it forms drops and likes to drip off our skin or make puddles on the ground. It doesn’t just spread out all over the place. If you don’t believe water likes to stick to itself, try this experiment.
Fill a cup all the way to the top with water, so full that any more water would overflow! Now take a penny and carefully drop it in to the water. You don’t want to make a big splash. What happened? Did the water overflow? Try another penny?
Chances are you can fit up to 20 pennies in the water without it overflowing! Did you think there was enough room in the cup to do that?
The water actually rises above the top of the cup. It doesn’t spill because water wants to stay together. This quality of water and other liquids is called “Surface Tension.” The tiny bits of water are built in a way that they act like very weak magnets, but they are still strong enough to handle the pennies in your cup.
The surface tension is also strong enough so that some very light bugs, like the water strider, can even walk on the water! Some lizards, called basilisk lizards, can run on the water! These specially designed animals take advantage of water’s surface tension. For them, the water surface is hard like the ground is for us! People can’t do this though, so make sure you can swim and have a grown-up with you if you plan to be in water!