What's the difference between RAM and ROM memory?

Everything you open on a device involves RAM. When you open a browser tab, for example, it gets copied from storage into RAM, allowing the processor to reach it quickly (a matter of nanoseconds). DRAM is the most dominant type of RAM, and it stores each bit as a charge in a tiny capacitor that gets refreshed thousands of times per second. It can't be refreshed if power is cut, so if that happens, everything stored there disappears. If you're a PC enthusiast or have built your own rig, you'll probably be familiar with the (now wildly expensive) DDR5 sticks they use.