THURSDAY, APRIL 14 TH  Please take out your notebook, homework check sheet, and last night’s homework  Warm-up: 1. What happens to the atoms or molecules in a substance as heat is added? 2. How do you know? 3. A visitor from another dimension comes to Earth and hears you talking about how atoms move at different speeds depending on the temperature. They don’t believe you because that’s not how things work in their dimension. Using materials that you could find in your home, how would you prove this to the visitor?

ATOMIC HEAT  Using the materials to the right, design a lab procedure that will allow you to prove to your visitor that hotter atoms/molecules move faster than colder ones  You may not need to use every material on the list  Water  Beakers (various sizes)  Popsicle sticks  Balloons (various sizes)  Ruler  String  Scissors  Camera  Thermometer  Table salt (NaCl)  Hot plate  Food coloring  Tin foil  Ice  Butane lighter  Timer

FOOD COLORING METHOD  Start with equal volumes of hot water and cold water  At the same time, add three drops of food coloring to each beaker  Observe the results

IN YOUR NOTEBOOK  Record your observations  Describe what the colors looked like and how they moved and mixed in the cold water.  Describe what the colors looked like and how they moved and mixed in the hot water.  What does the speed of the mixing colors tell you about the speed of the molecules in hot and cold water?

IN YOUR NOTEBOOK  Copy down the following sentences and fill in the blanks with the words increase(s) OR decrease(s)  Heating a substance _________ molecular motion.  Cooling a substance _________ molecular motion.  As molecular motion increases, the space between molecules _________.  As molecular motion decreases, the space between molecules _________.

MOLECULAR MODELS  Explain what happens as a solid turns into a liquid (melts) at a molecular level. Draw a picture to support your explanation.

MOLECULAR MODELS  Explain what happens as a liquid turns into a gas (boils) at a molecular level. Draw a picture to support your explanation.

MOLECULAR MODELS  Explain what happens at a molecular level as a gas is heated up. Draw a picture to support your explanation

MOLECULAR MODELS 

DISCUSS WITH YOUR TABLE  What holds solid and liquid substances together?

CONNECTION – COVALENT UNIT  Copy and complete the following in your notebook  As a substance heats up, the molecules are moving _____________ [slower/faster] and there is __________ [less/more] space between them. The intermolecular forces between each molecule ____________ [decrease/increase].  Gases have __________ [weaker/stronger] intermolecular forces than liquids.

CONNECTION - DENSITY  We typically assume that water has a density of 1 g/mL, but this is only true at room temperature.  In your notebook answer the following:  Do you expect the density of water to increase or decrease with an increase in temperature?  Why?

QUIZ TOMORROW