Change Detectives By Grant

At the end of the first semester we started Change Detectives with a mess scene with each different change explained throughout the unit. In the mess scene was salt in water, tartaric acid with bicarbonate soda in water, melted chocolate, burnt chocolate, melted icy-poles, spilt vinegar, frozen milk, Berocca in water and a lit candle. Each had a chemical, physical or chemical and physical change. A physical change is when no new substance is made and a chemical change is when a new substance is made

Salt in Water I think that salt in water has a chemical change(dissolves) and a physical change(looks more foggy). The change isn’t reversible*. I think the changes occurred when the salt dissolves it spreads so the water becomes foggy. *unless you have a desalination plant

Melted Chocolate I think that melted chocolate has a physical change only(becomes more like liquid). Reversible. I think the change occurred because the particles spread/expand and the chocolate moves more freely. The change can be reversed by putting the chocolate in a fridge, freezer or just leaving it out to dry.

Tartaric Acid with Bicarbonate Soda in Water I think that acid with bicarb in water has a chemical change only(causes fizz). Not reversible. I think the changes occurred because the acid and bicarb create carbon dioxide together so they make the water carbonated.

Burnt Chocolate I think that burnt chocolate has a physical(looks different and smells different)and a chemical change(changes the substance). Not reversible. I think the changes occurred because the heat changed it to an ash-like substance

Melted Icy-poles I think that melted icy-poles has a physical change only(becomes more like liquid). Reversible. I think the change occurred because the particles spread/expand and the chocolate moves more freely. The change can be reversed by putting the tubes in a freezer.

Spilt Vinegar I think that the spilt vinegar has a chemical change only(evaporating). Not reversible. I think the change occurred because the vinegar became a gas.

Frozen Milk I think that frozen milk has a physical change only( becomes solid). Reversible. I think the change occurred because the particles compact making it a solid. The change can be reversed by leaving the milk to dry or putting it in a microwave

Berocca in Water I think that Berocca in water has a chemical change only(dissolves). Not reversible. I think the change occurred because the properties of the tablet spread in the water.

Burning Candle I think that the burning candle has physical(wax melts) and a chemical change(keeps flame going). Not reversible. I think the changes occurred because the heat from a flame makes the other flame and makes the wax melt.

The water investigation proved that water has three states(solid, liquid and gas), the investigation evocative evaporation proved that vinegar and evaporate, Delightly(or delightfully) Dissolving proved how much salt could be dissolved in water, the fizzing investigation proved that using bicarbonate soda, tartaric acid and water, you could only make fizz with all of them together, Candle Capers proved a candle with a jar over it takes longer to go out if the jar is bigger and the Berocca experiment proved that Berocca dissolves quicker in warmer water.

Change Detectives has been great and I have learnt a lot!