How much does it weigh or hold?
We measure how much something weighs (or its mass) in grammes (g) or kilogrammes (kg). There are 1000g in 1Kg. We measure how much something holds, its capacity, in millilitres (ml), centilitres (cl) or litres (L). There are 10ml in a cl and 1000ml in a L.
Can you find different packets, tins, bottles or cartons of food and drink and sort them into things that are measured by its weight (mass) or its capacity. You'll need to look on the labels. Normally liquids will be by capacity. When you have done that can you order them by size?