This is the American Sign Language sign for POPCORN. It uses the 1 shapes popping up and down, alternately.
Show this sign to your toddler when you see popcorn in books or in magazines, even if you see it in videos. When you pop popcorn, show the sign before the popping starts, e.g., "We're going to make POPCORN!". Show the sign while the corn is popping, e.g., "Look/listen, we're making POPCORN!". Then, the best part, show the sign for POPCORN when are a eating popcorn! Always say the word as you sign it and offer small bites.
My son at 2 years would stand in front of the microwave and dance and sign for 2 1/2 minutes while our popcorn popped! I definitely knew what he wanted!