In an experiment, a control is used to establish a baseline to compare the results of the main experiment to. Having a control group rules out any environmental variables, such as temperature and... In an experiment, a control is used to establish a baseline to compare the results of the main experiment to. Having a control group rules out any environmental variables, such as temperature and...
Knives, including small pocket knives, are only allowed in checked bags. Only plastic and round-tip butter knives are allowed as carry-on blades. Most bladed items are allowed in checked baggage, including scissors, razors, swords, axes, box cutters and blade tools, if they are properly wrapped or sheathed.
Mace and pepper sprays are not permitted in carry-on or checked baggage. See our High-value, Fragile and Perishable Items page for more information about dry ice in baggage. Liquid nitrogen is permitted in checked and carry-on baggage.