Separate the pennies you have into two groups: one group with pennies dated before 1982 and the other with pennies dated after 1982. compare the two groups. record any similarities or differences in size or appearance that you notice between the two groups.

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

What type of electromagnetic waves does the human eye see as the colors red blue or green a visible light waves b radio waves c infrared waves d microwaves

What is one measurement needed to calculate the speed of an object?