You can make a scale with which to weigh air! A lamp with an ordinary light bulb will make the warm air you need. Materials - lamp - paper bags (2, same size) - sticks (2, long) - string - tape...
Going up!
Do you know that some people use a bag of hot air to fly? They really do. The "bag" is a huge hot-air balloon. The balloon can lift people because hot air behaves in a special solid or a liquid. So...
Tricks with heat
These tricks aren't really magic---they just look mysterious. Heat energy makes them work. Water ballet Materials - crayons - ice-cube tray - mixing bowl (large) - paper - scissors - water ...
What makes a teakettle whistle?
You don't have to watch a whistling teakettle to know when the water is hot. The kettle will \"tell" you when the water begins to boil. The kettle makes a long, loud whistle. When you whistle, you...
Little blocks of water
Why does lemonade get cooler when you put ice cubes in it? The answer may surprise you. The lemonade cools down because it heats up the ice! Ice cubes are a solid---little blocks of frozen water....
As warm as toast
If you spread cold butter on hot toast, the butter won't stay cold very long. Some of the heat from the toast passes into it. Soon the butter is warm, too---as warm as toast. Heat energy can spread....
A solid thermometer
Materials - cardboard - foil-and-paper candy wrapper - pencil - spool - tape Most thermometers you've seen probably use a liquid to measure temperature. But solids can be used to measure...
How a thermometer works
Is a pool full of ice water warm enough for swimming? Not for you! But for a penguin, it might be just right. You and the penguin have different ideas about how \"warm" the water is. You can easily...
Moving molecules
Here is a way to show that hot and cold molecules move at different speeds. A hot-and-cold contest Materials - bowls (2, large) - food coloring - medicine dropper - pan (bigger than bowl) -...
How hot is hot?
Which is hottest---ice cream, a glass of cool water, or a steaming-hot cup of chocolate? Of course, the chocolate is hottest. But it wouldn't be quite right to say that the ice cream and the water...