Heavy metal People have been using different metals for centuries. Gold was the first metal to be used Pure gold occurs naturally Some gold has been found in caves in Spain that was used about 42 000 years ago
Metallurgy A scientist who works with metals is called a metallurgist In the sixteenth century, Georg Agricola wrote a book called De re metallica (on the nature of metals) about the science and extraction of metals Agricola has been called the ‘father of metallurgy’ Today, metallurgy is an important field in science, which can lead to a whole range of careers
Uses of metals Metals are used for many different things You find them at home, school, in factories, in shops and on the roads It is hard to think of a place where we don’t find metals Metals are used so much because they are good at doing many things A lot of the metal objects we use are made of pure metal
A special metal Most metals are solid at room temperature Mercury (Hg) is the exception – at room temperature it is a liquid It melts at -39 oC Most metals melt at very high temperatures – Tungsten (W) melts at 3000 oC
Risk assessments Some people want to ban mercury because it Is very toxic If you breather in mercury or eat it it can cause breathing difficulties, hallucinations, memory loss or even death Scientists who use mercury have to carry out a risk assessment This means they use information about the hazards to reduce the risk to human health
Risky business The US EPA has announced plans to regulate the amount of mercury released in to the atmosphere from coal-fired power stations The problem is that mercury gets into the sea, and then into seafood When humans east seafood, they absorb the poisonous mercury Mercury levels are monitored in the air, seawater, seafood and humans
Questions What does a metallurgist do? (4) Describe the properties of metals. (5) The photos show objects made from different metals Choose the best metal for each object from the table of popular metals (6) Give a reason for your choice (6)
Questions Choose the best metal for each object from the table of popular metals (6) Give a reason for your choice (6)
Questions Some farmers keep cows in fields close to coal-burning power stations Explain why the grass, cows and their mile should be monitored for mercury levels (7) Suggest control measures that the government could use (7)
How to do experiments safely Clear desk and place on your stool under the desk No sitting down during practicals Collect and wear safety gear at all times One way system to reduce accidents Walk, don’t run Ask if you are ever unsure!
Using a Bunsen burner Collect equipment, share between group Examine equipment to see if there is any damage Check gas tap is working and connect Close air hole to ensure safety flame Leave on safety flame when not heating Heat on purple flame only Pack away while you wait Equipment will be hot, leave to cool down
Hot oven Your oven at home is made from metals, but which metals are the best for the job? Metals for ovens have to put up with very high temperatures AND the wires that work the electrical parts (like the light and the fan) need to conduct electricity well. Which metals are best for the job? You need to find out!
Workstation 1 Looking at appearance Look at the samples of metals at workstation 1. Write down observations about the appearance of each metal.
test tube holder small amount of metal test tube Heat Workstation 2 Effect of heat At workstation 2 put a small amount of one metal in the bottom of a test tube. Place the test tube in a holder and heat the metal over the Bunsen burner for a few seconds. Write down what you see. Repeat the experiment for the other metals.
Workstation 3 Electrical conductivity Test the metals with the conductivity tester at workstation 3. Write down what you find out.
Presenting results Design a table to show what you found out for each metal
Considering your evidence Discuss your findings in your group. 1 What properties do all metals have in common? 2 Which metals behave differently to the others? 3 What happens when metals are heated? What can you say about the melting points of the metals you tested? 4 Which metals would be good for making the different parts of an oven? 5 What extra information do you need to find out to make sure that the metals you choose are going to be the right ones to use in an oven?
Evaluation When you carried out the tests, how did you make sure that the tests gave a fair comparison between the metals? How could you improve the tests?
And finally… Name five metals Name five non-metals (use your periodic table)