Third Grade Homeschool Science Lessons on Heat Energy
Lessons and Experiments on Heat Energy
Following are some lessons/experiments my daughter and I have done recently on Heat Energy. Hopefully these will be useful to other homeschooling families. They are simple but they get the point across. We've had fun doing these.
Heat Energy -Friction/Fire Lesson/Experiment
One way you can make heat is to rub two surfaces together. This rubbing together is called friction. The friction you make when you rub your hands together warms your hands. Try it. Rub your hands together hard and fast. Do they feel warm?
Hold your hands to your face. Do they feel warm?
FIre is another thing that makes heat. It causes heat energy to work in anything it is near. Fire is a useful tool that God has given.
Many people use fire to cook their food.
Fire is useful for keeping warm, too. In very early times fires were built to cook food and to keep people warm.
When our country was very young, homes had big fireplaces. The fireplaces were used both for cooking and for heating.
Today people keep the heating fires in furnaces. The heat energy goes through ducts to heat the air in the homes. When people are cold they can turn up the thermostat and get heat.
FIre cannot burn by itself. It needs fuel and an invisible gas called oxygen. It also needs heat energy from something else to start burning.
Fuels for fire can be many things. Some fuels are solid. Wood and coal are solid fuels.
Other fuels are liquid. Oil and gasoline are liquid fuels.
Some gases are fuels. Many homes are heated by burning a special gas in a furnace. It is called natural gas. Another gas that burns is called butane. It is a source of heat for stoves and furnaces.
Remember, no fuel can burn without oxygen. Oxygen is a gas that can burn. It is in the air you breathe.
You will need these things:
~3 candles in holders
~1 pint jar
~1 quart jar
~clock or timer
1.Light 3 candles
2.Place the pint jar over one lighted candle
3.Place the quart jar over on lighted candle
4.Observe what happens to the three flames in 10 min.
5.Tell about what happened to each flame
Another Source of Heat Energy-Electricity Lesson/Experiment
Another source of heat energy is electricity. Electricity can be found in nature. It is called static electricity.
You have seen lightning flash across the sky during a storm. Lightning is the strongest static electricity. It is caused by friction in the air. A mass of cold air rubs against a mass of warm air. This rubbing together makes a great flash of light and heat energy. If lightning touches something on the ground, it can start a fire.
You can make static electricity too. The static electricity you make does not have as much heat energy as lightning, but it can do interesting things.
You will need;
~a small flat box
~plastic food wrap
~small bits of paper(tissue)
1.Put the bits of paper into the box.
2.Cover the box lightly with the plastic wrap.
3.Rub your hand on the plastic.
4.Observe what happens to the bits of paper.
5.Write what happened.
Another Activity to try.
You will need:
~hairbrush or comb
~dark room or closet
1.Take the mirror and the brush into a very dark place.
2. As you watch in the mirror, brush your hair very hard.What do you see?
3. Write about what you observed. What kind of electricity caused it?
Definition of Heat Energy Lesson/Experiment
In order to understand what heat energy is, it is important to remember that all things are made of tiny parts. These tiny parts are called molecules. These molecules are so small that you cannot see them without a strong microscope. Other molecules cannot be seen at all. It is the smallest part of anything that still is that thing. A molecule of water is still water even though you may not be able to see it. A molecule of sugar is still sugar even though you may not be able to see it. A molecule of sugar is still sugar even though you probably could not taste it.
When something is heated by friction, fire, electricity, the sun, or your body, the molecules begin to vibrate. The faster the molecules vibrate, the more heat energy there is.
Heat energy is the energy of vibrating molecules.
For this activity you will need:
~two clear glasses
1.Put hot water into one glass and cold water into the other
2.Let the glasses sit untouched for 2 minutes
3.With the dropper, very carefully put one drop of food coloring into each glass
4.Without touching or moving the glasses,observe what happens to the food coloring in the water. Watch for one minute
5.Draw two glasses and color showing what happened.
You can see how the molecules of hot water move faster than the molecules of cold water.
Finish the sentences with these words:
~ vibrate ~ ~ molecules ~ ~ heat energy ~ ~ hot~
1.The food coloring mixed more quickly with the _____________ water.
2. Molecules _______________ faster in hot water.
3. Energy of vibrating molecules is the same as ___________________.
4. The smallest parts of things are___________________.
Effects of Heat Energy Lesson/Experiment
Heat energy has an effect on things in different ways. Did you ever climb a ladder in the house and notice that the air is warmer near the ceiling? Perhaps you opened your refrigerator door and the cold air around your feet.
When water is boiling,steam and water vapor come from the kettle. Does it go up or down?
The air and the steam are both gases. Gases are made of molecules. When gases are heated, the molecules move very fast. As the vibrate, they also move farther apart.
The gas expands. It takes up more space. The same number of gas molecules in a larger space makes the gas lighter. As the gas gets lighter, it rises. As a gas cool, it contracts and gets heavier. The heavier gas comes down.
You will need:
~a small-necked bottle
~a pan of water
~a hot plate
1. Fasten the balloon over the neck of the bottle to trap the air inside.
2. Set the bottle into the pan of water. Put the pan on the heat.
3. Observe what happens to the balloon as the water in the pan gets hot.
4. Draw a picture to show what happened to the balloon.
5. Let the water in the pan cool. Add ice cubes if you have some.
6.Observe what happens to the balloon as the water in the pan cools.
7.Draw a picture showing what happened to the balloon when the water got cool.
Questions to go with the lesson:
1. What is in the bottle?_____________ a.water b.air c.nothing
2. Air is a ___________ a.gas b.liquid c.solid
3. When water gets hot the air inside the bottle_________________
a.contracts b.cools off c.expands
4. As the air expands, the balloon_____________
a. stays the same b.gets bigger c.gets smaller
5. Molecules in a heated gas_____________________
a. move apart b.come together c.break
Heat Changes Liquids/Changing Liquid to Gas
Heat energy changes liquids, too. Water is a liquid you know. It is the most important liquid on earth. Without God's gift of water, there could be no life on earth. No plants could grow. No animals could grow. No animals could live. Even you must have water every day.
Water is a very interesting liquid.It is the best one to study because it can take other forms. Water can be solid, and it can be gas.
Heat energy that changes water from one form to another. If you put ice cubes on a plate in a warm room, the ice cubes would melt. The water would change from a solid to a liquid.
Question: What would make the ice melt? Answer; heat energy.
The heat energy in the air makes the molecules in the ice move faster and causes the ice to melt. More heat energy will cause the water to change even more.
You will need these:
~ a hot plate
~ a pan or kettle
~ a one cup measure
~ clock or timer
1. Measure one cup of water into the pan.
2.Put the pan of water on the hot plate. Set the temperature control to high.
3.Observe as the water gets hotter. Notice how the water begins to move and bubbles form.
4.When the water is boiling set the timer for 5 minutes.
5.After the water has cooled for 5 minutes, use the potholder and take the pan from the heat.
6.When the water has cooled, pour it back into the measuring cup.
Questions to go with the experiment;
1.How much water did you pour into the pan?_______________________
2.When the water was boiling, what did you see?_____________________
3.How much water did you pour back into the cup?___________________
4.Where did the rest of the water go?______________________________
When water boils, the heat energy makes the water molecules move so fast that they push away from each other and escape into the air. They evaporate. They become a gas.
Heat energy from the sun or in the air of a heated room can cause water to evaporate. Evaporation takes longer than boiling, but it happens just the same.
You will need;
~ a glass of water
~ a ruler
1. Measure from the top of the water to the bottom of the glass.
2. Draw a picture of two cups, one labeled A and one labeled B. Record the measurement on cup A.
3. Leave the glass of water in a safe place overnight.
4. Measure the water again.
5. Record the measurement on the picture labeled B.