David is making lemonade he asked you could you some lemon juice and water the sugar starts to dissolve what can we do to speed up the dissolving process

We could (a) stir faster and (b) warm the mixture.

Stirring faster moves freshly-dissolved sugar away from the solid and allows new water molecules to contact with the surface,

Warming the mixture gives the water molecules more kinetic energy, so their collisions with the surface of the sugar will be more effective in removing the sugar molecules.

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.