When we open the oven to get out a pan of freshly baked cookies, we can feel the heat coming out of the oven. We can tell the temperature of the oven is a lot higher than the temperature of the room. If we stand outside in the sunshine on a summer day, we can feel the heat of the sun. We know we can feel heat, but what is heat?
Heat is a type of energy that can be transferred from one object to another. A warmer object will transfer it's heat energy to a colder object and raise that object's temperature. Heat can be transferred to objects in several different ways. One way is by radiation, and another is by conduction.
Science Experiments
Transferring Heat By Radiation
When you stand in the sunlight, you can feel the warmth of the sun. The sun can raise the temperature of your skin and body without even touching you. It transfers its heat energy to your skin by radiation. Radiation is the transfer of heat by electromagnetic waves.
Electromagnetic waves carry the heat energy from the sun to the earth transferring that heat to whatever object they touch. We can't see these wave, but we know they exist. We can feel the results.
Transferring Heat By Conduction
Have you ever walked on a sidewalk in the summertime in bare feet? Did the concrete feel warm? The sun transferred its heat to the sidewalk via radiation and caused the temperature of the concrete to rise. When you stepped on the sidewalk, your feet were colder than the concrete so it gave some of its heat to your feet. This is called conduction. Conduction is the transfer of energy from one object to another through direct contact.
Radiation And Conduction Experiments
Let's do a simple experiment to demonstrate how radiation and conduction works. You just need four supplies: a toaster, a piece of bread, butter, and a butter knife.
Radiation Heat Transfer Experiment
For this experiment, you are just going to need a toaster and a piece of bread.
Hold the piece of bread in your hand. Notice the temperature and appearance of the bread. Next, place the bread in the toaster, then start the toaster. Look inside the toaster..
Do you see the red wires? The wires are red because electricity is flowing through them and heating them up. Never touch these wires. The electrical charge is so great you could get electrocuted.
Without touching the toaster, feel the air around the toaster? What do you notice about it? The heat is radiating from the hot wires and increasing the temperature in the air and object around them.
When the toaster is done and the bread pops up, carefully grab the bread and hold it in your hand. Notice the temperature of the bread. Is is different than when you placed the bread into the toaster? Look at the appearance of the bread. Is the color or texture different than before it was toasted?
The heat radiating from the wires transferred to the bread. This heat not only increased the temperature of the bread, it caused chemical changes in the bread. We can see this by the color and texture change. The bread turned from white to brown and from soft to crispy.
Conduction Experiment
While that toasted bread from the radiation experiment is still warm, place of pat of butter on the warm toast with the butter knife. Notice what happens to the butter. It should be melting. The toast is warmer than the butter, so it transfers its heat to the butter. This warms the butter past its melting point. This transfer of heat from the toast to the butter is conduction.
I love simple science experiments and projects that demonstrate seemingly complicated concepts. Try this easy experiment at home to explain how heat is transferred to your kids.
More Science Units for Kids
- Animal Cells (Edible!) K-6th
- Animal Report Forms K-8th
- Crystals - How to Grow Crystals K-6th
- Hatching ButterfliesK-6th
- How to Make a Lava Lamp - K-6th
- Why do Leaves Change Colors K-6th
- Homemade Battery Experiment K-6th
- Pop Rock Science Experiment K-6th
- Simple Machines – Inclined Planes
- Solar System Worksheets
- Squishy Circuits (PreK-6th)
- Weather Unit (free printable unit) K-3rd
Marci is a Christian wife, homeschool mom, science geek, softball coach, hockey mom and blogger, who needs her morning coffee, hair done and make-up on before attempting of those things. You can find her blogging at The Homeschool Scientist
