The lesson will teach students the difference between mass and weight with a hands-on activity and instruction. Students will simulate a reduction in gravity (i.e. a reduction in an object's weight) using water's buoyancy. The research question that the students will address is: "Will an object's mass and weight differ in and out of water?"

Teachers Note:  Prior to the lesson be sure that the balances that are to be used can be submerged in water and that they balance to horizontal or zero out while in water.  Different manufacturers and materials may prohibit the use of certain balances underwater since different materials may have different buoyancies that may impact the use of the balance underwater.  Please note that there is an optional variation of the activity that uses a 1000 mL beaker instead and does not require the balance to be submerged.