a torch
Termites.
You can put a hole in the wooden box to make it lighter. By removing some material from the box, you will reduce its weight.
You can put a hole in the wooden box to make it lighter by reducing the amount of material in it.
Holes or helium can reduce the weight of a container, if you are going down the helium route, you better make sure it is sealed.
Well you could remove the air from the metal box and put a very light gas in it such as hydrogen or helium that would make it marginally lighter, but I suspect given that these puzzles are mostly riddles that the answer we need here is lighter fuel, thus turning the metal box into a lighter?
Fire always works for me --------------------------------- Normally you would take things OUT of a box to make it lighter.
A hole can be put into a box to make it lighter. By removing material from the box, its overall weight will decrease.
You can put a small piece of flint and steel inside a box to create a spark for lighting a fire. Alternatively, you can place a lighter or matches inside a box to provide a convenient way to light objects.
helium (?)
There would be more friction between the heavy wooden box and the floor than the light wooden box. This is because the friction force is directly proportional to the weight of the object pressing down on the surface, which in this case is the weight of the box. The heavier box would exert more pressure on the floor, resulting in greater friction.
The answer is a hole. This is because you are getting rid of some of the box so it will be lighter.
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