Year 5 SCIENCE CLUBS CHEMISTRY Fichas sobre Chemistry Part 1: Class three - Indicators , creado por cecilia valente el 16/01/2023.
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Creado por cecilia valente
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Creado por cecilia valente
hace casi 2 años
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Class Three: indicators
You will need:
* access to the internet, look for pH scale colour. I recommend this one https://www.usgs.gov/media/images/ph-scale
because it shows how fish dies when water turns acidic. You can use this data to remind them that sea water should be slightly alkaline
PLEASE, BEAR IN MIND THAT CABBAGE JUICE GIVES OUT
SLIGHTLY DIFFERENT COLOURS FOR ACIDS AND ALKALIS
SEE HERE
* digital pH meter if you have one. I bought one cheaply via Amazon.
* five transparent cups or small plastic measuring cups per each group in a V formation (ready in the tray)
* WELCOME YOUR PUPILS BACK TO SCIENCE CLUB AND ASK THEM HOW
THEY ARE. Are they ready for another adventure in the marvellous world of chemistry?
* Get them to split into groups of three
* Appoint an assistant dearest or two (swap and stop method)
* Tell them to keep their shoulders back and their va-va-voom
* Remind them of the club's motto: Grab it, learn it, lock it
* Remind them that scientists are sceptical: they don't believe anything until they see proof. So each class they must ask you to prove that what you tell them at the beginning of the class is true. Say: Prove it!
* remind them that EVERYTHING happens in the tray
*Start with a recap of last class:
* ...Today we are going to learn about indicators. Show me your index finger? What do you use it for? To point to things and people. We use this finger to show something.
* An indicator points to something in an experiment.
* you have already used an indicator last time we met. Can you tell me what was the indicator last week? ( A: It was the litmus paper strips.)
* Today we work on another indicator. It is a natural one. It will smell but it will be fun and it will point to the truth: it's a 'stinkimus pinkimus' with va-va-voom.
Do you believe me? No? I will prove it to you
* Let's PROOVE IT. GOGGLES ON and, if your bite your nails or your hands are scratched, wear disposable gloves.
* Pour 100 ml of cabbage juice in each and any of the cups in the tray
* Now take the measuring spoon with the yellow tape (it's one spoon full) and fill it with
1) vinegar wait until each group has done, fill one spoon full of vinegar and then count to three. At three, let them pour it on one of the cups (it does not matter which side of the V they choose but once the group has chosen, take that side as the acids' side). Compare the new colour with the pH scale: what colour is it? And what number does it match? Is it 1 to just under 7? THEN IT IS ____ (Let them say ACID - give points)
3) now do the same with the water, using the cup next to the one you used for the lemon juice Has the colour of the indicator changed? Not really. It just got diluted but the colour is basically the same. What does it confirm? (A: that water is not an acid)
* so using all the data with have assembled today we can say beyond doubt that cabbage juice is an ______ (let them say INDICATOR)
* HOW DO WE KNOW? It changes colour when it is mixed with acids and alkalis/bases
* Do these colours matter|? Yes because each colour is connected with a number of the pH scale and each number has a meaning
