Dana was given the following information

Year wolves
2003 10
2004 20
2005 30
2006 15
2007 10
2008 11

A question which must come to most people (including me) is what is  ‘Carrying Capacity”.  A quick investigation indicates that this means the capacity of an environment to support a number of species.  Using the data above suggests that in 2004 an environment could support 20 wolves BUT  in the year 2007 something had happened to the environment and it could only support 10 wolves. Why?

The ‘Why’ introduces lots of questions.  Did the environment get smaller? Wolves survive on hunting smaller animals …did they find somewhere else to live? Was there a drought  in the environment which caused the smaller animals to decline in numbers?

To really find an answer to this question you need to find a lot about wolves, their diet, the, effects of weather on them, wolf predators, and others.

# Dhanashree (13) asks “Why is sound a longitudinal wave?”

Dhanashree, thank you for the question. I asked my team about the question and they arrived at the following answer….which I was not happy with …….

There are two types of ways in which waves manage to travel ……. Longitudinal and Transverse. I can see the way the waves they develop BUT need time to think about how to explain them. Longitudinal waves travel along straight lines away from the source …  I am trying to understand how the particles associated with the travelling disturbance (sound) travel in each of these ways.

How do the particles of air (in longitudinal movement) make further particles of air move in the same way…if they are doing forward and back vibrations? The vibrating air particles (or particles of any gas) must be moving forwards as well as moving back and …thus moving the wave forward.

So …to answer your question …..sound is created by things vibrating, the drum skin vibrates, up and down when it is hit…….the air above the drum skin follows this vibration, and the air next to the vibrating air , starts to vibrate and so on. This is your longitudinal vibration.

With Transverse vibrations the particles move up and down. Like waves …which stay in the same place.  More thinking about this later.

# Sam (13) asked “What are the building blocks of cells? And does it vary for each cell?”

Up-dated  24/10/2019

Thank you for your question Sam. As usual I put it to a member of my team. Lets see what they say and then, maybe, I can add to it.

Thank you for that team. Cells are obviously very, very important. We, and all, living things are all made up of them. But what about the cells themselves …what are they made of ? A little research shows that all cells contain  proteins, lipids, carbohydrates and nucleic acids. Let’s look at the role of each of these groups of compounds.

Proteins are all important (they are made of things called amino acids BUT enough of that). Proteins have important roles in cells. They provide the cell with energy, they fight infections they help move other components  around the cell.

Lipids are basically fats and therefore are a source of energy. The proteins will access the lipids to help them in their tasks and the Carbohydrates are another source of energy

Nucleic acids are better known as amino acids that make up  RNA and DNA structures. These are probably the most important, ………no I am wrong, the nucleic acid component of the cell needs all the other components to survive. They will not last long if left alone. The nucleic acids are the messengers of the cells. In simple terms they have, in their structure , the message that enables the construction of a living thing (animal, plant) from the activity of the rest of the cell. You could say they are the managers.

A little addition ……. what is an amino acid? Firstly as an acid it contains the -COOH group of atoms. CH3COOH is a familiar acid

Shown here in its structural form

known as acetic acid (vinegar).

Amino acids basically contain NH2 groups instead of CH3 . One of the simplest is glycine.

Proteins also (in some cases) act as catalysts (something that enables a reaction to occur. In these situations they are called enzymes.

I really hope this is helpful. Thanks for the question.

# “Questions about the Universe” by Lewis Jordan Sexton (13)

Lewis, thank you very much for your thoughts and the questions in your own mind that you are thinking about. Wow.

I’m tempted to tell you a story about a question that my wife asked to her mother when she was about your age. “Mother what is the Universe and what was the big bang?” Her mother’s reply was “They are very big questions, I think your time is better spent making sure that this planet we are living on lasts as long as possible, rather than worrying about the Universe”

For readers who are interested here is the what Lewis submitted. Lewis, if you would like me to remove it send a request in the comment box below.

My thinking is that we have no idea, at the moment, whether any of the the thoughts put forward by various scientists are valid. It seems to me to be a classic case of a set of developing scientific ideas as the tools and thoughts of the the scientists develop.

For example notable scientists like Newton and Einstein developed ideas relating to your thoughts  which were effectively disproved. This is in fact the way that all scientific arguments progress. For example ……When Albert Einstein was formulating his ground-breaking theory of gravity in the early 20th Century, at a time when astronomers only really knew of the existence of our own galaxy, he used the simplifying assumption that the universe has the same properties in all its parts, and that it looks roughly the same in every direction wherever, in the Universe, an observer happens to be located. Like Sir Isaac Newton two hundred years before him, he assumed an infinite, static or “steady state” Universe, with its stars suspended  motionless in a vast void.

One of the driving forces behind the development of science thinking is to disprove earlier scientific thinking. It is called falsification.

It was a philosopher,Karl Popper who said you can only have a scientific theory if it can be proved to be false. This is what has happened to the scientific theories of Einstein and Newton. Some of their ideas/theories on gravity and the nature of the Universe have been successfully disproved. New theories by Hubble (the telescope scientist) disproved the stable Universe idea’s of Newton and Einstein. This led to new scientific ideas of an expanding (rather than a stationary static state)  Universe …which could be false? To illustrate how scientist are challenging Hubble’s ideas it is now known that the Universe is expanding at an accelerating  rate than rather than a steady rate …….the mystery continues.

Have a look at this website The Physics of the Universe.

I shall continue thinking and possibly updating.

# If pressure on a gas is increased what will happen inter-particle force?” asks Prince (13)

You have to think of how you are going to increase the pressure of a gas.

I can think of two methods …..imagine the gas in a Coke tin. The gas particles are rapidly moving around, bouncing of each other and the sides of the container. We can increase the pressure by

(1) decreasing the volume of the coke can ….the particles therefore will hit the sides more often (increasing pressure) or (2) increasing the amount of gas in the can which again increases the number of gas particles that hit the side of the can, again increasing pressure.

In both these cases the intermolecular forces are quite small. Most gas particles are fairly inert , they have intermolecular forces but they are slight. Water H2O and NH3; (ammonia) are probably exceptional.

HOWEVER as you increase the pressure further the gas molecules have less room to move and they get closer to each other …the intermolecular forces increase UNTIL they are so strong (because there are so many molecules in the small space) that the gas becomes a LIQUID. This is helped if you reduce the temperature at the same time (molecular movement is temperature dependant).

Science Master

# “Why does soft serve ice cream increase in volume in a milkshake as it’s melting?” asked Tim (13)

Thanks for your comments team. I’m afraid you are wrong. My research suggests that Soft Serve has less fat than ordinary Ice Cream. The real difference is the amount of air in the ice cream and the temperature at which it is stored. In my view it is the amount of air that is crucial.  When Soft Served is warmed I would suggest that the air in the fat which makes up the ice cream makes the ice cream expand to a greater extent than the ordinary ice cream.

You could try a little experiment to confirm this. Take two equal samples of ice cream (soft serve and ordinary) of the same weight (use kitchen scales). Let them warm up. Allow the ordinary ice cream to reach the same temperature as the soft serve (ordinary ice cream is usually kept at a lower temperature than soft serve). Make sure that the two samples are in the same kinds of containers. Do they expand to the same degree?

What do you think the role of the air is in this process?

I hope that this gives you a clue to any differences that you see.

# Jessie (13) asked “Why do humans age until 100 years old in average and not further?”

The Hydra are a group of invertebrates (animals that do not have backbones) that look like tiny tubes with tentacles protruding off one end. They grow only about 0.4 inches (10 millimeters) long and eat even tinier aquatic animals AND they seem to be immortal, they can live forever without aging.

So why can’t we? There are several reasons. One of them is the inability of our cells to continually divide. The cells of bacteria seem to be able to divide, and form two daughter cells endlessly. Our cells only seem to be able to divide about 60 times …. so after that time the part of the body that the cells support begins to degenerate (die).

The cell dividing and subsequent regenerating is controlled by our DNA. It tells the body what to do. Over the years our DNA becomes damaged by a variety of things and the instructions for regeneration are lost.

However the hydra survives so maybe that will be a route for researchers to find some answers to the problems we face.

# Keith (13) asked a question about thermal papers in cash machines.

Keith’s question
More and more places are using thermal paper as a form of receipt paper for customers. With time the information fades. How can one scientifically go about recovering information which may have faded from thermal paper.

Keith, many thanks for the question. I never realised that thermal(heat sensitive) paper was used in so many places and that it is also the basis on which the polaroid camera worked.

Thermal paper is made using a collection of dyes which exist as colourless crystals that become coloured when they interact with an acid.

For those who enjoy their chemistry you might have come across adding a dye called phenolphthalein to an acid solution. The dye changes from colourless to a deep purple.

The applied heat (from the cash register machine) melts a layer in the paper which contains acid crystals. The liquid acid then interacts with the layer below it which contains a colourless crystalline dye which changes colour as the acid interacts with it.  The print then shows. The acid quickly becomes crystalline again.

Over time the print does begin to disappear.

A little investigation.

Obtain an old till receipt which your adults do not want to save. Put it onto an ironing board and with a hot (care) iron, iron it.

Stop

To make it more scientific predict what you think might happen before you carry out the experiment. Any ideas, if so you have a hypothesis.  Now find a very old (fading) receipt and using a hair drier blow warm air onto the BACK of the receipt. Again predict.

I think I’ll stop there. Many thanks for the question Keith. Please comment or ask another question.

# “How do compounds and elements work together?” asks Candice (13)

Thanks for that information team. It does illustrate the relationship between elements and compounds and the way in which they work together. To understand this a little more you will have to know  more about the structure of  the atoms which make up the elements. All of the atoms of the 118 elements have a different number of protons in their nucleus and this dictates the way in which they behave in the formation of compound.

Below is a drawing of an atom of the element Lithium with the electrons, protons and neutrons.

Crossword.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

# Hello (13) asks “How do tectonic plates work and influence earthquakes?”

Quite right my friend it’s all about convection. Warm water, air, oil, or any liquid/gas stuff  will move upwards (rise) when it is heated. Why. Think about it.

Lets think of an experiment (this is a science blog) where we can test this idea and then move on to the question that Hello asked.

The experiment

You will need a beaker of water, some pencil lead, 3  A batteries, two leads with attached crocodile clips and some food colouring and a dropper

Connect the pencil lead to the batteries using the leads. As the electricity passes through the pencil lead, the pencil lead will heat up. Drop the attached lead into the water. Look carefully at the water, what is happening. If you put a small screen behind the beaker of water and shine a torch on the water you will be able to get a better view of what is happening to the water.

OR

Drop a small amount of food colouring into the water.

Hopefully what you will see are convection currents that have been created by the water close to the lead  warming up and beginning to rise. The next question is WHY.

Warning. Do not use mains electricity. It could be very dangerous and kill you.

Why does the water rise?

When the water particles(molecules) come into close contact with the heated pencil lead they gain kinetic energy (see Science Master Special Energy), they move faster. The water molecules spread out so that in any given space there are less water molecules (less dense). This means that gravity comes into action and the colder water can begin to move into the space where the warm water was. The warmer water ‘floats’ on top of the cold water. The cold water then gets warm and and more cold water moves in and the original warm water floats up higher in the beaker. As the warm water rises it gets colder and more dense and eventually will join the column of cold water that is moving (by gravity) downwards toward the hot pencil lead. Wow…..I hope you can see the picture

The movement of the tectonic plates is caused by convection currents and it is this movement that can cause earthquakes. Hopefully when you watch the excellent video below you will see the links.

Hello. If you would like to question anything, please make a comment or ask another question.

(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)