Acid: For older kids and adults: A substance that produces hydrogen (H+) ions in water. Common examples include citric acid (lemons and oranges), acetic acid (vinegar), and carbonic acid (soft drinks).
Base: For older kids and adults: A substance that produces hydroxide (OH-) ions in water. Common examples include soaps, oven cleaners, and Tums or other antacid medicines.
Payload: Something a rocket brings into space, such as astronauts, supplies, or equipment.
Rocket: Something shaped like a cylinder that can be shot very far or high by using combustion to make it go.
Thrust: A force that acts backward away from the rocket. As the force thrusts one way, the rocket shoots the other.