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.

I hope this gives you some answers to your question. If not please comment or ask another question.

PS  You and your friends might be interested in the crossword puzzle background. Its all about atoms, elements and compounds. You can download the crossword and the answers from the link below.

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)

Preethikha (13) asked a question about planting corn seeds in clay.

Preethikha you asked your question on behalf of your friend  Johan who appeared to be having trouble in growing his corn seeds in clay. I asked my friends about this and these were the ideas that they arrived at. 

The roots of the corn plant are very complex like most plants and they NEED oxygen . Clay is an important soil, it is full of nutrients which are important in providing the growing plant with food , HOWEVER  it is very different from most of the soils that we meet in our gardens.

Soils are composed of three types of particles: sand, silt, and clay.

The size of the particles varies, with clay having the smallest size and sand the largest.Smaller sized particles pack more closely together and slow the flow of water through the soil.The composition of a soil can affect the permeability (flow) of water through it.

There is the possibility that your friends corn seeds produce roots which are then ‘drowned’ in the surrounding clay soil. Investigate your friends soil and compare it to other soils in your neighbourhood. My next question for you is how would you go about investigating it ?

 

James asks “What happens to the cactus flower the day after it flowers?”

Many thanks team you are right. The cactus needs it’s flower to be pollinated.

What do I mean by pollination?

Lets look at that picture more closely (see below). Pollination is the process of transferring a pollen from the male part of a plant (the anther) to the female part of the plant (the stigma). It is better that the transfer process is from the male part of one plant to the female part of another similar plant.

What helps this happen – Bees, flies, bats and lots of other insects.

What happens then – A fruit develops from the flower site and in the fruit are seeds, lots of them. These fruits are eaten by animals and by this method the seeds are spread around the surrounding environment.

What experiments could you think of to test these thoughts (hypothesis)? Any idea then click on the ‘Leave a Reply’ button below.

Malina (13) asks – If blood has iron in it , is it magnetic?

magnetic-blood

Apologies accepted. Yes Malina, it was an interesting question.

What I need to ask you, is do you know about electrons? If you do then you will know that elements like iron are made up of atoms. Each atom of iron has a nucleus of protons (positively charged particles, 26) and neutrons (uncharged particles, 30) and surrounding the nucleus are the electrons (26 negatively charged  particles). It’s the way the electrons behave that makes thing interesting. In normal elements like carbon, silicon and sulphur all the electrons are ‘tied’ to the nucleus. They cannot leave the nucleus. In the metallic elements some of the electrons are ‘tied’ but the others are free to move away from the nucleus. This is why metals can conduct electricity (which is the movement of electrons along a metallic wire). It is the free electrons which dictate whether an element is magnetic or not.

Still with me? Hope so – if not you could ask another question.

The electrons themselves are like small magnets and some of them ‘pair up’ as magnets can do. For some elements who have an odd number of free electrons you end up with a lot of free electrons for the others you get complete pairing. See below  for a pairing image.

magnetic-electrons

A metal is classified as ferromagnetic (very magnetic) if it has a lot of unpaired free electrons. iron and nickel are two examples.

When the iron atom begins to combine with other elements to form your hemoglobin there is further pairing of electrons between the iron atoms and the things it is combining with so it loses it’s magnetism.

That was a lot to understand. Hope you have managed.

 

Ernie(13) asks -“What is at the centre of a black hole? What would happen if you fell into one?”

black-holes

We obviously know something about gravity. We know that it is a force that is generated by the mass of an object. The bigger the mass the bigger the force that it exerts on other objects. So we feel the force of Earth’s gravity on us and the Earth feels the force of the  Sun’s gravity on it. The Sun’s gravitational force keeps the Earth on an orbit around it. If it didn’t exist the Earth and all the other planets would start wandering in space.

Black holes are thought to be a source of a massive gravitational force, because of their mass , which is constantly increasing, and they don’t just pull other matter to them they pull light in as well …thus a black hole. No light – darkness.

So to your question.  I think you could now answer that yourself.

Apply asked “If the pressure on the surface of a gas is increased. What will happen to the inter particle force?

A fascinating question. I asked my friends to look at this and they came up with a couple of definitions which might dictate the way I try to answer this question.
intermolecular

Your question seems to be directed at intermolecular forces between similar particles/molecules 

In a past question I talked about the way water molecules are attracted to each other by things called ‘hydrogen bonds’. This aids the formation of liquid water at very high temperature and low pressures. The molecules ‘like’ being close together. Another molecule is that of carbon dioxide – these are not attracted to each other so strongly. To attract each other they need to be ‘pushed’ much closer together, only then will they form a liquid. For some molecules like butane you need really high pushes because the attraction between the molecules is so small. For some other molecules there is no force of attraction, this can almost be described as repulsion. The gases, Helium, Nitrogen and Hydrogen  are only liquefied under immense pressure (push) and low temperature (low temperature slow the individual molecules down) conditions.