We looked again at how we calculate speed, and the units we use. We then looked at the difference between velocity and speed. Can you remember what this is?. Can you remember anything that has speed but no velocity? ( think of things that go round in circles)

We used ticker timers to see what happens to the tape when you move at a steady speed, getting faster and getting slower.

The wall of death – speed but no velocity

Today we changed the strength of the acid we used by adding distilled water. This changes the concentration of the reactant. We measured the time for the cross to disappear again, with sodium thiosulphate.