Why do I feel hot, but that girl over there doesn't?
The water is warm.
Emily happily walks onto the beach. After a few minutes, Emily begins to feel overly hot. However, she notices that the girl nearby does not look distressed due to the heat.
It's so cold in this deep water.
Emily remembers from science class that the reason she feels hot is because the sun is transferring heat energy in waves, and because there is no need for particles, it is very efficient. She remembers that this is called radiation. Emily also realizes that her dark bathing suit is absorbing the heat, while the nearby girl's white bathing suit is reflecting the heat which is why she feels hot and the other girl doesn't.
Yuck! This cupcake from the metal plate is warm! But why wasn't the cupcake from the plastic plate warm?
Emily takes a step into the ocean and the water feels warm. Then Emily dives into the water and feels colder as she gets deeper.
Oh! Now I remember. . .
Emily remembers from science class that the reason the water is colder the deeper she gets is because the warmer water particles rise to the top pushing the colder particles to the bottom of the ocean. This is a convection current and a form of convection.
Emily is hungry so she takes a bite of her two cupcakes. The cupcake from the plastic plate tastes normal, however the cupcake from the metal plate is warm, and Emily wonders why the two cupcakes are different temperatures. Then Emily remembers from science class that conduction, the transfer of heat in solids, which happens through direct collisions of particles, is the transfer of heat that is occurring.
Emily also understands that the cupcake from the metal plate has a lot of heat energy because metal is a material that heats up quickly and efficiently, which makes it a good heat conductor. However, the cupcake from the plastic plate does not have as much heat energy because plastic is a material that does not heat up quickly or efficiently, which makes it an insulator.