Title: TASK: The bathtub experiment
Course: Project week - Leuphana-Copy > Section: What is renewable energy? (science focus)

You are going to do a demo experiment in class (i.e. only one group of students or your teacher will perform the experiment while the others observe and document what happens).

What you need:

You need a transparent container into which you can fill water at the top and – at the same time – drain water at the bottom. It should resemble the figure to the right. For example, you can use:

- a PET bottle (cut off its bottom and insert a valve into the bottleneck, or – if you do not have a valve, use three different lids, one with a small-sized hole, one with a medium sized-hole, one with a large-sized hole)
- a transparent plastic bucket into whose bottom you can punch a hole and insert a valve
- a water dispenser that has an opening at the top and a faucet or valve at the bottom
- a water glass or beaker glass that you can fix to a lab stand in a slightly tilted way

Experiment:

Place the container and lab stand under a faucet. You are going to simultaneously fill water into the container and drain water from it at different rates. Note down your observations after each step.

Before you start, review the necessary vocabulary first. Name the different parts of the experiment apparatus by dragging the labels to the correct location.

Ready? Then carefully perform the following steps. Note your observations after each step.

1. Turn on the faucet and open the valve or drain. Observation?

2. Now close the valve/drain (for the outflow from the container). Observation?
3. Open the valve/drain again; slightly turn off the faucet so that less water than before enters the container. Observation?

[fa-info-circle] This task cycle is adapted from: Niebert, K. (2017). Den Klimawandel bremsen lernen. In U. Kattmann (Ed.), Biologie unterrichten mit Alltagsvorstellungen – Didaktische Rekonstruktion in Unterrichtseinheiten (pp. 92–105). Seelze: Friedrich Verlag.