Page 33 - Microsoft Word - SCI KS2 Y3 Y4 gs.doc

Science Y3/Y4 – Water – week 6

DILUTING AND DISSOLVING

Truth to Teach (Source)

To learn the meaning of ‘dilute’, ‘dissolve’, ‘solution’, ‘insoluble’.

To discover why birds’ feathers are waterproof.

To conduct fair tests to see which substances dissolve in cold and /or hot water.

To appreciate why we use washing up liquid to clear grease off crockery.

Way to Work (Means)

1. Review the previous half term’s work through question and answer, creating a ‘Fact File’ of
water from the lessons covered so far.

2. Put the above new words on the board to establish whether any of the children already
know the meanings. Dictionaries could be used.

3. Show the children a selection of drinks containing water, letting them list them on their
sheets. Talk about which ones are dissolved and which ones are diluted. Ask which ones
are neither dissolved nor diluted?

4. Pour some oil in a jar and ask the children whether they think that oil will dissolve in
water. Talk about birds’ feathers being waterproof because they are covered in oil. Ask if
anyone has seen birds covered in black oil after tankers have leaked oil. How do people
clean the birds? Show how washing up liquid poured into the jar of oil and water
disperses the oil. Compare this to washing up greasy dishes. The liquid breaks up the oil
into small drops which makes the water look cloudy.

5. Let the children perform fair tests on dissolving substances in cold then hot water.

6. After completing the worksheet, gather the children to share their discoveries. Talk about
the danger of mixing unknown substances together as various chemical reactions may
occur.

Learning for Life (Fulfilment)

The children should appreciate the need to know whether substances dissolve in water or not
as such knowledge is vital in cooking and in everyday life. They should have a greater
understanding of the danger of mixing unknown substances together.

31