This project is almost the same as the first project using the manometer but this time, we'll make a scale by which to measure the pressure.

We can tape a ruler to the open-ended tube, and tape another ruler to the side of the aquarium. Put this one upside down, so that the "1" mark is toward the top of the water level.

Now, when you put the funnel down into the aquarium, note the depth of the funnel, according to the ruler, and also note the height of the colored water in the tube, according to its ruler.

Write down the depths of the funnel and heights of the tube so that you can know how far the water in the tube goes relative to the depth to which you lower the funnel. From your notes, you can make a graph. The graph can help us estimate how much higher the water in the tube will go if we lower the funnel a certain distance further.

We can also lower the funnel into a container of other liquid, such as cooking oil or liquid soap, and see if the other liquid exerts the same amount of pressure.

If we had a really long glass tube for the open-ended tube, and about 10 feet of plastic tubing between the funnel and the glass tubes, we could check the pressure of a swimming pool! That would really be fun!