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Exploring how heat changes a solid into a liquid.
Have you ever left an ice cube on the kitchen counter and come back to find a little puddle of water? Where did the ice go, and how did it change?
Ice is just water that has become very, very cold! When water gets cold enough, it turns into a solid. A solid is something that keeps its own shape. If you put an ice cube in a round cup, it stays shaped like a cube. It is hard, cold, and you can pick it up with your fingers. In science, we say ice is the solid state of water.
Quick Check
What do we call water when it is a hard, cold solid?
Answer
Ice
When we add heat to ice, something happens. Heat is a type of energy that makes things warmer. Heat can come from the bright sun, from your warm hands, or even from the air in a warm room. When ice gets warm, it reaches a special temperature of (). At this point, the ice cannot stay a solid anymore. The tiny parts inside the ice start to move around more!
1. Pick up a small ice cube. 2. Hold it in your closed hand for 30 seconds. 3. Open your hand and look at the water. 4. Your body heat moved into the ice cube to make it change!
Quick Check
What must we add to ice to make it change into liquid water?
Answer
Heat (or energy)
Melting is the word we use when a solid turns into a liquid. As the ice melts, it loses its cube shape and turns into clear, runny liquid water. Unlike the solid ice, liquid water doesn't have its own shape. It flows and fills up the bottom of whatever container it is in. If you spill it, it spreads out everywhere!
Imagine you are eating a purple popsicle outside on a very hot day. 1. The sun shines on the popsicle. 2. The popsicle gets warmer and warmer. 3. Sticky purple liquid starts to drip down your arm. 4. This is because the solid popsicle is melting into a liquid!
A snowman is made of many tiny pieces of ice called snow. If the sun comes out and the temperature goes above : 1. The snow absorbs heat from the air. 2. The solid snow turns into liquid water. 3. The snowman gets smaller and smaller until he is just a puddle!
What is the solid form of water called?
What is 'melting'?
Liquid water has its own shape and stays in a cube like ice does.
Review Tomorrow
Tomorrow, look in your freezer. Can you remember the name for the hard, cold water inside? Can you explain what would happen if you put it in the sun?
Practice Activity
With an adult, put one ice cube in a dark cupboard and one in a sunny window. Watch them to see which one melts first!