At what temperature does water become steam? Is there any way to prevent water from vaporizing at certain temperatures? How does pressure affect boiling water and steam?
Different forms of Matter
When studying the physics of water and heat, you'll want to explain to your child that water can be present in three different forms: solid ice, liquid water and vapor, or steam. When water is cooled to a certain temperature, it expands and becomes solid ice. When ice is heated to a certain temperature, the ice melts into water. Finally, when water is heated, it vaporizes and becomes steam. When the steam cools to a certain temperature, the vapor condenses into water droplets again.
Most of the time, water is a liquid because the temperature is above 32 degress Fahrenheit, the temperature where it becomes ice. Other things that surround us, including rock and metal, can become a liquid, but it takes a tremendous amount of heat for this to happen. Volcanoes are a good example of rock that is hot enough to become a liquid.
Showing How Materials Change
To demonstrate how water changes its physical form from ice to water to steam, you can do the following simple project. The following questions and answers will help you navigate a discussion with your child regarding this science project.
Pour a set amount of water, such as one cup, into a plastic container. You can use any amount of water, but be sure to measure it. Leave room for the water to expand, and mark the water level with a sharpie so your child can see the changes. Place the container of water in the freezer and allow it to freeze completely.
Take the container of ice out of the freezer and show your child how the water expanded when it became ice. Leave the container on the counter until it melts completely. Have your child touch it to see how it feels as ice, then as water.
Pour the water into a pot and turn on the burner on high. Show your child how the gaseous bubbles form as part of the water reaches 212 degrees and begins to boil. Hold a container above the pot and show your child the steam that is coming up off the pot of water. Show your child how the steam condenses back into water as it cools on the container. if you like, you can put a candy thermometer in the water so your child can see at what temperature the water boils.
Water freezes at 32 degrees Fahrenheit. Water boils and can become steam at 212 degrees Fahrenheit. You will notice not all the water instantly vaporizes and becomes steam at once; this is because a stove will not heat all of the water evenly. Explain to your child that not all of the water cools evenly either, so the water will freeze unevenly as well, starting with the outside and working its way in.
Turn the boiling water off after a few minutes, let it cool, then pour it back into the plastic container. Chances are that there is less water than there was before. This is because some water vapor is lost into the air as it boils. Explain to your child that if the pot was left boiling long enough, all of the water would turn to steam and be spread through the air, leaving the pot empty.
How does water turn to steam? Learn the science behind molecular changes and try this fascinating experiment to see the power of steam firsthand.
Are your children asking, "What causes steam?" Use this simple experiment to teach them about steam and introduce them to some basic rules of chemistry.