That means that, together, they will change into something that is neither an acid nor a base. We have learnt that when an acid and a base are mixed (in the right amounts), they will neutralise each other. Which of the products do you recognise? Write their names and what they are used for in the table. Bases which dissolve in water are called alkalis.Īll of the products in the picture below contain bases. After feeling the difference between the acids and bases, the learners can go back to their desk to complete the activity.Īs an extension, you can also let learners take note of the difference between the dry powder for washing powder and then how it feels when it is mixed with water.They must take note of what they are feeling and should dry their hands between each substance.Once the learners have filled in the table to identify the products, get them to come up to the front in groups to put their fingers in the bowls to feel the different substances.Arrange the bowls in a row, alternating between a base and an acid.Pour some lemon juice into another bowl and some vinegar into the last bowl.Mix each of the bases (washing powder, handy andy, baking powder) in separate bowls with some water.Place the bowls in a row on a desk in the front.labels for each bowl showing the product that is in them.Instructions and materials for the demonstration are supplied here: The next part of the activity is a demonstration which you can set up beforehand in the front of your classroom. All of these household products contain bases. It just means that they have been mixed with other substances so that they are not so corrosive.įor this activity, learners must first identify the products in the photograph provided. This does not mean that they are completely harmless. Other bases are mild enough to be used as cleaning materials in and around the home. Do you see the yellow corrosive warning symbol? Sodium hydroxide is a strong base used in laboratories. They must be handled carefully and always while wearing appropriate protective clothing, such as lab coats, gloves and safety glasses. Strong bases react corrosively with other materials and can burn your skin. The same hazard symbol that is used to warn people of the dangers of acids, is also used for these bases. We can think of bases as the chemical opposite of acids.Īs with acids, there are some bases that are extremely dangerous. In the process, both the acid and the base will lose their unique characteristics.īases and acids have chemical properties that are the opposite of each other. This means that the solution made up of the acid and the base becomes something that is neither an acid nor a base, but neutral. When an acid and a base are mixed together in the correct ratio, they will neutralise each other. You should handle containers with these formulae printed on them with care. Even though you have not learnt how to write chemical formulae yet, we have included them here. The following table contains the names and chemical formulae of the three most common laboratory acids. Can you see he is wearing protective clothing, gloves and safety glasses? Look out for this label on bottles which contain corrosive substances, such as strong acids. We will refer to them as laboratory acids. These acids are most often found and used in laboratories and certain industrial processes. It would be very dangerous to taste them. Scientists always wear protective clothing when handling these acids. They can cause serious burns on your skin. Some acids are very dangerous and must be handled carefully. Laboratory acids Concentrated hydrochloric acid is very corrosive and dangerous. Investigation: Is red cabbage paper suitable as acid-base indicator?ĭoing investigation, recording information, interpreting information Hypothesising, doing investigation, recording information, comparing, interpreting information Investigation: How does litmus respond to acids and bases? 9 in more detail, also covering the pH scale, and the reactions of acids and bases.ģ.2 Properties of acids, base and neutrals (2 hours)Īccessing and recalling information, observing, comparing, sorting and classifyingĪctivity: Preparing and testing red cabbage juice with acid and baseįollowing instructions, practical skills, observing, comparingĪctivity: Making red cabbage indicator paper They will look at acids and bases again in Gr. We will then look at acids and bases in the laboratory and the basic properties of acids, bases and neutrals. This links to Life and Living and the senses. We will also first look at how we experience acids and bases in foods. The approach is to start from the known and introduce the topic through learner's experiences with everyday acids and bases. This is the first time learners are introduced to acids and bases.
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