1. Thermal Expansion Hotter = Bigger What happened to the sidewalk?

2. Thermal Expansion Therm- means heat Expand- means to get bigger Thermal expansion is the process of things getting bigger as they get hotter. Things also get smaller as they get colder.

3. Hotter is Bigger At 25°, the T-shaped piece fits inside the gauge. When heated, it does not. The brass ball will not fit through the ring. If both are heated, the ball fits through. A bimetallic strip is made of two metals that expand at different rates. Since on side becomes longer than the other, the strip bends.

4. What is temperature? How hot something is. How do we measure temperature? But what are we really measuring? The length of the red line. Then why do we measure in degrees and not meters (or millimeters)? What is a degree?

5. Temperature What temperature really measures is how fast the particles in an object are moving. The faster the particles move, the more space they take up. The object has to get bigger to make room for the particles to move.

6. Colder is smaller Take two empty plastic water bottles. Fill one with tap water, fill the other with hot water. Place the hot bottle in the freezer for an hour, then compare it to the first bottle. What do you see?

7. Why do flying lanterns fly? The fire heats the air inside the lantern. Then what happens? The air expands (its volume increases). Did its mass change? Yes, then its density must go down. (You’re dividing a smaller mass by the same volume.) Less dense objects float.