HMH Unit 2.3 Pgs 131-132

HMH Unit 2.3 Pgs 131-132

Pgs 131-132

Explaining Patterns in Melting

• Substances change their state at different temperatures.

• The substances in the graph change from solids to liquids with different amounts of energy (heat).

Multiple Choice

Which substance has the highest melting point?

• olive oil

• water

• beeswax

• sugar

• chocolate

Multiple Choice

Which substance has the lowest melting point?

• olive oil

• water

• beeswax

• sugar

• chocolate

Open Ended

Would the substance that melts at the lowest melting point also melt at the highest melting point? Explain in complete sentences.

Metals

• This metal, which was once a solid, is now a liquid. Different metal have different melting points.

• For example, tin has a lower melting point that iron.

Multiple Choice

To turn this liquid back into a solid, it needs to be at its ______ point.

• freezing

• boiling

Phase In, Phase Out

• Changing the state of matter is an example of a physical change.

• This is also called phase change.

• It means that going from solid to liquid to gas and back again does not change the matter present.

Phase In, Phase Out

• Imagine a teakettle filled with water. The kettle is heating up. What is happening to the water inside?

• The water is a liquid. When it reaches its boiling point, it will turn into a gas.

• 
  

Phase In, Phase Out

• As the gas tries to escape from the kettle, it whistles (remember that gas particles move very fast)

• After teh kettle is removed from the heat, it will start to cool.

• This changes the gas back into a liquid.

Open Ended

If the liquid from our kettle example is put in the freezer, what will happen to it? Explain in complete sentences.

Open Ended

What changes happen to water when making rice? Explain in complete sentences.