When you are teaching preschoolers about temperature, provide opportunities for them to experience differences in temperature. Comparing hot and cold things, and deciding which object is coldest, makes the concept of temperature more accessible. Touching and feeling objects of different temperatures make it an engaging activity. Fill a bowl with water. Dip a cotton ball in the bowl and squeeze out excess water. Let preschoolers rub the wet cotton ball over their arms. Use water of different temperatures, and let preschoolers decide which is the coldest and warmest water. Tell them to blow across the wet area and ask them to describe the feeling. The arm feels cooler when you blow your breath across it. When the tiny water drops from your breath evaporate, they remove heat from the skin, making it feel cooler.
Changes in temperature are measured by using a thermometer. Place a thermometer outside and let the preschoolers record the temperature. Bring the thermometer inside and check the difference. Explain the numerals and tell them that the lower numerals mean colder temperatures. Lay the thermometer on the table and put a wet cotton ball across the bulb of the thermometer. Let the preschoolers blow across the thermometer and observe the changes in temperature. The temperature decrease when you blow on the cotton ball. The water on the cotton ball evaporates, taking heat from the thermometer and lowering its temperature.
Talk about different clothes that you wear depending about the outside temperature. Let preschoolers hold an ice cube in their hands. Put a glove on one hand and let them compare how cold the ice cubes make their hands feel. Make a giant thermometer. Let children suggest types of clothes that you wear at different temperatures. Draw the clothes next to the numerals on the thermometer. Put pictures of shorts and dresses next to numerals indicating high temperatures. Coats and hats are worn on cold days and they are placed on numerals for low temperatures.
Encourage preschoolers' curiosity by letting them touch a variety of surfaces. A tour around the preschool classroom can provide a range of surface temperatures. Ask them to touch a wooden table, the floor, walls, glass window. Bring some metal objects and let the children touch the objects and compare them to the other surfaces in the classroom. The different surfaces should not feel the same temperature. Metal feels colder than wood since metals carries away heat quickly. Arrange the surfaces from coldest to warmest and ask them to see if there are any similarities between cold and warm surfaces.