What makes a birdfeeder work? If it hangs upside down like that, why doesn’t all the water pour out?
Materials -
Two identical bottles
A pin, safety pin, needle
Water to fill the bottles
Cup to hold water
Basin or yard for spilling, done outdoors, or a big sink.
Fill both bottles with water, label one A and the other B. Pour water from A into the cup and bring the opening of the bottle under the surface of the water in the cup. It will stop flowing. It works because the air can’t escape. The bottle will be upside down but the water doesn’t come out.
Then poke a hole with the pin in the top side of bottle B.
Ask the class what they think will happen? WIll B do the same thing that A did?
Tell the class they will hear a familiar sound, but we have to listen closely. Turn bottle B over and it will start spilling out into the cup. The sound will be bubbling. Let them see the bottle and the air bubbles going to the top as the whole amount of water spills into the tub you brought.
The bubbles are coming straight from the hole. The air and the water can’t occupy the same space. Bubbles in and water out.
We talk about how A and B were different. It was just a hole. The air rushed in and the water came out. Case ‘B’ was full of bubbles of air. Simple sentences can be written down by the teacher. Students write what they saw and what they learned in their journals, often best as each is capable with guided writing. When finishing, each student reads their entry to three other students.
