Why does the voltage not drop when you plug in a power strip?

The sockets are in parallel.

What does change is the amount of amperage that you are pulling. That’s why your house has circuit breakers, so that if you pull too much, they will flip off.

Think of it like water. You turn on the tap in two rooms, you still get hot or cold water, it stays the same. But using it does reduce the amperage, like if you use water on all the taps and flush some toilets, you reduce the water pressure. Insufficient amps coming in to the house can result in blown fuses if you plug in something that draws a lot of power like a hair dryer or large appliance. Thats why they’re divided up into circuits, it evenly distributes the load that way. And of course, the code calls for more amps coming into your house than was required fifty years ago.

^ This.

The difference between voltage and amperage.

Electrical engineering textbooks going back nearly a century use this analogy.

It’s not about the voltage…it’s all about the wattage of each appliance plugged into that outlet/circuit. Exceed the wattage and you will blow a fuse.

There is no voltage drop because there is no load.
Voltage is like source water pressure and remains constant. Amperage is the like the flow of the water through a pipe. Resistance, (the load) is like the spigot that controls the flow of the water.
Sorry @Cruiser , you can only exceed the wattage of a appliance if you exceed the rated/applied voltage. You’d be forcing too may amps through the resistance of that unit.
Too many appliances on a circuit draws excessive amperage and trips the circuit breaker, if there is one, or burns out the fuse, if there is one.

We may be saying the same thing @kritiper in different ways as I did leave out amps…you can plug as many 120v appliances into a 120 V socket or strip and once the cumulative wattage of said coffee maker and hair dryer exceeds… depending on how you do the math, either cumulative wattage of the plugged in appliances is often overlooked as to the amperage of the circuit that was installed. Most homes will have 15 amp circuits which a hair dryer and a couple bathroom lights in the same circuit could blow and why microwave oven are almost always on their own circuit.

The outlets are in parallel so the voltage is the same. If they were in series it would be a different story. You can plug in all kinds of stuff but you have a power budget that cannot be exceeded. Power in watts is a way of describing the amount of current at a given voltage. Most circuits in residential are 15 amp for the entire set of outlets connected to that breaker. If you exceed 15 amps you will pop the breaker. 1500w is the general rule most follow when adding up devices. This is why it is common for a 1000w hairdryer to trip a breaker

@Cruiser It could also depend on if you’re looking at Watt’s Law or Ohm’s Law. ?

Watts is not a law it is a unit, ohms law is an equation. DC Power is commonly referred in equation terms as IR^2 or also Current*Voltage. AC power is a bit more complicated but the same principle.

…And AC voltage is not constant BTW, it’s sinusoidal. Technically speaking both you and Cruiser are more or less correct.

Jeeezus typo I^2R