Science Day Preparation and Subject Knowledge
States of matter and Reversible/irreversible change
Year 4 NC;
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Compare and group materials together, according to whether they are solids, liquids or
gases
Observe that some materials change state when they are heated or cooled, and measure or
research the temperature at which this happens in degrees Celsius (°C)
Year 5 & 6 NC;
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Compare and group together everyday materials on the basis of their properties, including
their hardness, solubility, transparency, conductivity (electrical and thermal), and response
to magnets
Know that some materials will dissolve in liquid to form a solution, and describe how to
recover a substance from a solution
Use knowledge of solids, liquids and gases to decide how mixtures might be separated,
including through filtering, sieving and evaporating
Give reasons, based on evidence from comparative and fair tests, for the particular uses of
everyday materials, including metals, wood and plastic
Demonstrate that dissolving, mixing and changes of state are reversible changes
Explain that some changes result in the formation of new materials, and that this kind of
change is not usually reversible, including changes associated with burning and the action of
acid on bicarbonate of soda.
Glossary
Liquid = a substance that flows freely but is of constant volume, having a consistency like that of water
or oil
Solid = firm and stable in shape; not liquid or fluid
Gas = an air-like fluid substance which expands freely to fill any space available, irrespective of its
quantity.
Acid = a substance with particular chemical properties including turning litmus red, neutralizing alkalis,
and dissolving some metals (PH less than 7)
Base = is a substance that can react with acids and neutralise them (PH greater than 7)
Chemical Reaction = a chemical reaction is when a substance (or a few substances) change into
another substance
Acid-Base reaction = the process when an acidic substance and a basic substance combine to form a
new substance
Science Day Experiments- How do they work?
Fizz inflator= the baking soda and the vinegar create an ACID-BASE
reaction and the two chemicals work together to create a gas, (carbon
dioxide) Gasses need a lot of room to spread out and the carbon dioxide
starts to fill the bottle, and then moves into the balloon to inflate it.
Ice-cream in a bag = the salt brings down the freezing point of the icemaking it colder, which then freezes the milk inside the bag.
Starch slime= the glue is a liquid polymer. This
means that the tiny molecules in the glue are in strands like a chain. When
you add the liquid starch, the strands of the polymer glue hold together,
giving it its slimy feel. The starch acts as a cross-linker that links all the
polymer strands together.
Laundry detergent slime= the borax in the laundry detergent reacts with the
water and polyvinyl alcohol in PVA glue, making a stretchy and squishy
substance (again linking polymer strands).
Blobs in a bottle= the oil stays above the water because the oil is lighter than
the water or, more specifically, less dense than water. The oil and water do
not mix because water molecules are attracted to other water molecules and
can loosely bond together (drops.) whilst the oil molecules are attracted to
other oil molecules. However, the structures of the two molecules do not
allow them to bond together.
When the Alka-Seltzer sinks to the bottom it dissolves and makes a gas. As
the gas bubbles rise, they take some of the coloured water with them. Then, when a blob of water
reaches the top, the gas escapes and the water sinks again.
Film canister rocket= When you add the water it starts to dissolve the AlkaSeltzer tablet. This creates a gas call carbon dioxide. As the carbon dioxide is
being released, it creates pressure inside the film canister. The more gas
that is made, the more pressure builds up until the cap it blasted down and
the rocket is blasted up.
Fizzy lemonade= carbon dioxide is created when the lemon juice (acid)
reacts with the baking soda (base). This makes the bubbles in the lemonade.