Melt+it+down

Explain what happens at a substance’s melting, freezing and boiling points. State how the melting point and the freezing point of a substance are linked. Explain the effect of impurities on the melting and boiling points of substances. Use melting and boiling point data to decide whether a substance is pure.
 * Objectives (what you will learn this lesson)**

**Starter**
 * review completed work
 * key term quiz

**Activities**

> media type="file" key="ES8_Ge102_03ani.swf" width="640" height="480" > media type="file" key="ES8_Ge102_04ani.swf" width="640" height="480" > a. What temperature is the freezing point of water? > b. How is the freezing point related to the melting point? > c. What is the temperature at which water boils? > d. If we continue to heat the water the temperature stays the same, why? What is the energy being used for? > media type="file" key="ES8_Ge103_11ani.swf" width="640" height="480"
 * 1) Complete the quiz on melting and boiling points.
 * 1) Use the particle diagram to find out what happens to the particles when substances change state.
 * 1) Answer the following questions as full sentences:
 * 1) Analyse the graphs on freezing points and answer the questions
 * 1) Investigate the [|differences between freezing pure and salty water]
 * 2) [|Analyse the data] on the boiling points of salty water
 * 3) Answer Q10,11, 12a and 12b from Exploring Science 8

**Summary** Review completed classwork / key term quiz

**Homework** Download complete the gapfill on [|Melt it down], print-off and stick into your exercise book. You can copy and complete if you have a problem printing.