The purpose of a scientific experiment is to find answers for specific questions. Often an experiment lasts long, is very complicated and expensive. We present you in detail some of the experiments we conducted on our expedition.

We designed a few simple experiments for you, so that you get a notion how scientists work. We explain clearly which questions we wanted to answer with the experiment, including how to formulate a hypothesis from a question, which methods we used and what materials we needed. We conducted these experiments employing the submersible and we made accurate documentations with photos and video. But before we were going to do that, we wanted to know from you which result you expected and why.

We exactly explained the outcome after we did the experiments.

Yeast sees the deep sea

A yeast experiment at school

Styrofoam und pressure

Some information about yeast


Originally we know yeast because we use it to bake bread, to brew beer and to make wine and all this for already a few thousand years.

However, that yeasts are living organisms was firstly described by Louis Pasteur (1822-1895) in his book “Études sur la bière“ (Studies about the beer).

Yeasts are unicellular fungi, which grow to a size of 10 micrometer (a tenth part of a millimeter). Yeasts are heterotrophic that means they eat organic material (sugar, protein, fat) which is produced by other creatures. They use oxygen to break down sugar into water and carbon dioxide and they utilize the released energy for their metabolism.

If there is no oxygen around, yeasts can live at least for some time and with less cell division. Then, the yeasts turn the sugar into the less energy rich ethyl alcohol (instead of water) and carbon dioxide. This is called fermentation. We utilize the carbon dioxide for example to let bread dough rise or to aerate beverage. The yeast itself provides us with vitamin B. Yeast extracts are used as flavor enhancer in food. In biotechnology sterile yeast extracts are used as culture media for other types of fungi or bacteria.

Yeasts either reproduces by budding and cell division (asexual) or they produce spores (sexual).

Yeast visits the deep-sea

The origin of the word experiment is Latin and means trial, proof, examination.

In science, we use experiments to answer a question we have so to speak to nature. The suppositions for an experiment are that we exactly know the conditions under which we make the experiment (in the deep-sea for example, the pressure, the water temperature, the light and so on) and that we can reproduce it. When you want to do an experiment there are 3 phases.

Let’s take the yeast experiment as an example.

The first phase starts in the head.

We think about a question we want to answer, for example:

“Does yeast survive for a few hours under deep-sea conditions?“ Now, we make a hypothesis: a hypothesis is an assumption. Since we know some facts about yeast and the deep-sea we assume that the yeast will survive.

“Yeast survive a stay in the deep-sea for a few hours“.

Then we think about how we can prove it and how to investigate it that means we think about the method.

We need not only to know “how do we do it?” but also “what do we need for the experiment?” The material is of special importance when we are on board of a research vessel and are on the open ocean for a few weeks. We cannot go shopping and if we have forgotten something, we have to ask our colleagues (if they have it) or in the worst case we cannot do our experiment.


Living yeast is sealed in a plastic bag, fixed at the outside of the submersible and taken with the dive. The dive lasts for 8 hours, the yeast is in a depth of 2500 meters for 5 hours. After the dive the ship’s cook tries to bake bread with the yeast.


Yeast, 3 little bags, tape, cable ties, submersible with cameras video camera and lights, a cook, all the ingredients for the bread, oven and kitchen utensils, paper, pencil, camera for the documentation of the baking, some hungry crew members (not neccessesaryly essential, but maybe the deep-sea bread tastes different from the control bread?).

The second phase is the practical perfomance.

We conduct our experiment.

1. Before we divided the yeast in 3 plastic bags, we take one part and keep it for later- also to bake bread with it.

The reason for this is that we have to assure that the yeast is alive before the experiment and that the cook can make bread with it. This is called a positive control.

2. We put the same amount of yeast into 3 plastic bags.

The reason for this is that we want to assure that the outcome of the experiment is not at random. Therefore we use replicates. It could be that the yeast is behaving incidentally different than usual. Or it could be that one of the bags has a little hole and we do not recognize it.

3. We fix the 3 plastic bags at the outside of Alvin and take them to a depth of 2500 meters.

4. The cook prepares bread with the deep-sea yeast and the control yeast.

The third phase is in the head again.

We have the results. Now we evaluate the results, draw the conclusions and voilá we have answered our question.

Does Yeast Survive an excursion to the deep-sea?

If yes, what can we learn from this?

If yes, under which conditions does yeast live?

If no, what can we learn from this?

If no, what could have killed the yeast, the high pressure, the darkness, the low temperature?

The experiment in practice

As is so often the case that reality differs a bit from theory. After a few discussions with the experienced Alvin pilots, we had to rethink how we could take the yeast with us. The pilots told us that the use of plastic bags was not a good idea, as they always crack open because of the rest of the air inside. A plastic container was not good either, because there is also air it and therefore the container would crack as well. In the end there was nothing else to it but to use the plastic bags. Pat the expedition leader had the idea, that we should also take some of the unrise yeast dough with us.


                                      Well-packed yeast dough                                                 Yeast before the dive

However, we decided to mount the double sealed plastic bag with the yeast and the one with the dough between the titanium sphere and the external wall instead onto the basket of the submersible.


                             Sack with the yeast and the bread dough                                 Gavin mount the sack

This was for safety only. Imagine, if the plastic bags crack open, the yeast and the dough could not only smudge our boxes but also blur Alvin’s windows.

The day before the dive, we persuaded the chief Larry Jackson, who makes the fresh bread everyday, to give us some of the bread dough. To prevent the dough from rising before the dive, we put it into the fridge. Very early the next morning at 6 o’clock, we wrapped the dough and the yeast tightly with two layers of plastic each. Then we fixed the sack with several cable ties to the submersible.

At 7 o´clock perfectly on the scheduled time after Alvin’s recovery we jumped to the submersible. The outcome was as expected. The bag with the dries yeast was broken and seawater had mixed with the yeast forming a lump. The bag with the dough was also burst and the dough oozed out of the sack.


                                    Yeast dough after the deep-sea adventure                   Yeast from 2500 meter depth

                                                                                Dough and yeast afterwards

At least we had enough dough left for the kitchen. Larry quickly added some flour, because the dough seawater mixture was a little bit thin.


                                                     Jerry a bit skeptical                                Jerry kneading the dough


                                        The finishing touch                                                                    We will see...

Into the oven. After one hour we had our result- the first deep-sea bread of the world. It was not as big as the control bread from the day before, but after all: it looked like bread.


                                             Looks like bread                                                            … smells like bread

We were wondering, does it taste the same or is it too salty? Bettina, Sabine, Sigrid and I had to serve as test takers.


                                           … feels like bread                                                           … and tastes like bread

As you can see all of us tasted it and we found in one consent that it is not as airy and fluffily and as normal bread but that at least it tasted like bread.

Jerry refused to test our dried yeast. He told us that there would be pizza this evening and that he could not risk making the pizza dough with yeast. The whole crew was looking forward to the dinner and if he snafus it there would be a mutinity. So we are going to take the yeast back home with us.

If you want to test it just write and we send it to you.


Now to the questions we wanted to answer. Does yeast survive a trip to the deep sea?

Yes, yeast survives in from of bread dough.

The open question is, survives yeast also in from of dried yeast?

If yes, what have we learned from it?

We learned that plastic bags are not suitable as wrapping in the deep-sea, because they break. Moreover the dough rose during the journey to the deep. Probably even several times and this is always bad for dough as Larry told us. The dough was relatively small and the yeast was still inactive when we took it out of the fridge. The outside temperature was already 25°C (77°F) in the early morning. The water temperature at the surface was 28°C (82,4°F). This temperature continually decreases with increasing depth, but the yeast had enough time to become active when the sack was fixed to Alvin, during the descent and ascent of the submersible and during the recovery at the end of the dive.

Result: yeast does not die because of the high pressure or darkness or low temperatures. At least not within 5 hours. Furthermore the salty seawater does not harm the yeast.

A yeast Experiment at school

Here is an experiment with yeast, which you can do at school.

Question: Does yeast survive dark- and coldness?

Hypothesis: Yeast survives darkness and coldness


Balloons, dry yeast, sugar, water, fridge, a cupboard or drawer, measuring tape, paper, pencil, clock.


1. Put in each balloon a pack of dried yeast, add 3 teaspoons of sugar, add 11/2 jiggers of water and close the balloons with tight knots.

For the fridge balloons use cold water so the yeast has the correct temperature right from the start.

2. Measure the perimeter of each balloon.

3. Put some of the balloons in the fridge. This is your test whether yeast can survive the low temperature and the darkness of the deep-sea

Put some of the balloon in the drawer at room temperature. This is to test whether yeast growths in darkness.

The rest of the balloons stay in the light at room temperature. That is the controls.

4. Wait and watch what is going on with the balloons.

5. Take the balloons out of the fridge and put them in the warmth.

What goes on, when the yeast in the balloon warms up?


In the balloons he yeast has everything it needs to live: food and water, therefore it growths and divides. In doing so it produces the gas carbon dioxide, which inflates the balloons. You can measure the balloons perimeter and calculate how much gas the yeast has produced per minute.

The yeast in the fridge should have done nothing or hardly anything, because it is too cold for its metabolism. When you put the yeast into the warmth also the fridge yeast should start to produce gas.

Light does not play a role for the metabolism of the yeast.


There you find some suggestions for experiments with yeast

Styrofoam under pressure


What happens to a Styrofoam cup under pressure?


As pressure is effective in all directions the cup will shrink.


Styrofoam cup will be fixed outside of the sub and taken with the dive. The dive is going to last for 8 hours; the cup will be in 2500 meters depth for 5 hours. After the dive we are going to measure the size, the volume and the appearance of the cup.


Styrofoam cup, cable straps for the submersible (equipped with a video camera, camera and light), ruler, Styrofoam cup with measure, binocular microscope, paper, pencil


1. We fix Styrofoam cups on the outside of Alvin.

2. We fly to the target depth, the cups are exposed to the pressure and cameras/video cameras record what happens to the cups.

3. We resurface

4. We examine the cups: One control cup, which was not exposed to the pressure, one cup for section for the microscopic examination and one cup we save for show and tell.

We measure the size

We measure the volume

We examine the surface under the binocular microscope and take a picture

The Styrofoam Experiment

The Styrofoam experiment will be carried out during the dive number 4265. We want to observe how Styrofoam behaves under the high pressure of greater depths. Styrofoam is a synthetic material, brought onto the market by the German company BASK as early as 1951. The base materials are small pearls of Polystyrol, which is obtained from crude oil in a very complicated procedure. The sugar like pearls gets foamed with the aid of foaming agent and heat and gets turned into small pellets. These pellets can be forced out into almost any shape with heat and pressure. The complete Styrofoam comprises 98% air. It is very suitable as packing and insulation material. But also many items of daily life are made out of Styrofoam. For example decorations and party cups.

Today, we are going to take some of these cups with us into the depth. To keep their shapes, we stuff them tightly with paper towels. Pilot Pat fixes one of the cups on Alvin’s basket and aims one video camera at it, before the dive.

Additionally to the video, Monika will take photos of this cup in 100 meters, 200 meters and 350 meters depth.

Can we expect a deformation of the cup? If yes, in which way?

Here is the answer: Styrofoam cups get considerably smaller under high pressure.

Explanation: The high water pressure forces the air out of the plastic material.

Monika reports that it is not necessary to take the cup down to 2500 meters water depth. The cups start to shrink much earlier and have already reached the size you can see on the photo at 300 meters. They do not become smaller anymore, even not in higher depths.


                                     Styrofoam cup after the dive                                           Standard size and shrunk