G4 Conservation of Mass (400 – 500)_01

Imagine you place a piece of paper on a triple beam balance. You observe and record its mass. Now you fold the piece of paper in two and place it back on the balance. What do you predict the mass of the folded paper will be compared to the unfolded piece? Do you predict the mass of the paper will have been altered in some way? What do you predict will happen to the mass of the paper if you crumpled the paper into a tight ball? Will the mass be the same or different from before?

What if you tore the paper into tiny pieces and placed all the pieces back on the balance at the same time? What predictions would you make about the mass now? Will they be different or remain the same? In all cases, the paper’s mass will remain constant. A physical change of matter does not affect its mass. Does this work for all types of matter? Give it a try!

Try placing a large lump of clay on the pan of a triple-beam balance. Carefully observe and record the mass of the clay. Take the clay off the balance and now pull the clay into very tiny pieces. Place all the tiny pieces back on the balance. Once again, carefully, observe and record the mass of the tiny pieces of clay. Was the outcome of your experiment what you predicted? 

Perhaps the mass before and after were really close, but not exactly the same? Does this make you doubt what you learned earlier about physical changes not affecting mass? No need to worry, you have Science on your side. Look closely at the tips of your fingers. That’s right! You found the missing mass. It wasn’t missing after all. The tiny bit of missing mass is stuck to the tips of your fingers. What other objects could you try this with? Maybe something that does not stick to your fingers?