Lesson Starter Tell me what is on the board – pH scale What is the purpose of the pH scale? – To tell us how strong or weak an acid/alkali is What do we use in order to see these colours?- indicator What do the different colours tell us? Example Household examples

Learning Intention To learn about neutralisation and how we can use it to prevent the damage of acids/alkalis

Experiment: challenge 20 minutes to create a test tube rainbow We know that different acids and alkalis have different pHs and so would create different colours but your challenge is to create the rainbow using just one acid and one alkalki Best rainbow gets a prize

Experiment: Challenge Apparatus Test tube rack 5 test tubes Acid Alkali Universal indicator pH scale Instructions Place 2 fingers of water in each test tube Place 5 drops of universal indicator in each test tube The rest is for you to work out! I’ve given a few instructions to start off, the rest you will need to work out! Don’t forget you are using harmful substances so will need to be wearing goggles. Start the countdown and after the time is up get all the teams to bring their rainbows to the front with their name on it for judging. Award the points and tidy up the experiment.

Neutralisation Add Alkali Add Acid Acids Alkalis

How could you stop the pain? Bee sting- pH 3 Wasp sting- pH 9