“Where do dogs come from?” – asks Sidrah

evolution2

Thanks for the suggestion. Lets see if I can explain it?

The dictionary definition of evolution is: It is a process of formation or growth. An aeroplane evolves from a collection of its parts. A picture evolves from the actions of a painter. A plant evolves from a seed.

In the biological sciences it has a special meaning as it studies the how and why living organisms change over time.

Living things pass on their traits (characteristics) from one generation to the next. All of us inherit a set of genetic blueprints from our parents. But those blueprints are never copied exactly from one generation to the next. Little changes occur with each passing generation and those little changes can become very big changes over a long period of time. These changes can reshape living things, and biological evolution has then taken place. Look at the video below it shows the changes that resulted in who you are now.

Dogs, like humans were very different millions of years ago.

Have more questions …. then ask another question.

Why does your hair stand up when rubbed with a balloon? was Kim’s question

Kim. I think we have something called ‘static electricity’ at work here. I asked my team to try to explain what ‘static electricity’ is.

static
As my friends have said we have met electrons before. These were moving  electrons. They were moving along a wire carrying their charge with them. Here we have electrons that are not moving, but they still have an electrical charge, so they are static.

Lightning is thought to be caused by static electricity collecting in clouds.

But now for your question Kim. When you rub your hair with a balloon. Some of the electrons are moving from your hair to the balloon. Or it might be the other way around …. some might be moving from the balloon to your hair. At the moment we don’t know which is happening. However whatever way it happens one of the objects (hair or balloon) loses electrons and becomes positively charged and the other object (hair or balloon) gains electrons and becomes negatively charged. Then we apply a famous rule about negative and positive charges …..like charges repel, unlike charges attract  soooooo  because we have a negative and a positive charge we have attraction. Your hair is attracted to the balloon, the balloon is attracted to your hair.

think you could work out a way to find out which of your two materials (hair or balloon) is the collector and the giver.

Have a think. You can then give your answer in the ‘Leave a Reply’ box or Ask another Question.

Dino asked ‘Why are stars in the night sky?’

Dino I asked my friends about this and I think I probably asked them the wrong question. These were their answers.

stars1

I was thinking about why stars are in the night sky and not in the day sky?

I think that they are not in the daytime sky because of a great big star that is quite close to us. The Sun. During daytime we are facing the Sun so it lights up our sky, and hides the stars, because they are not bright enough to shine through the Sun’s brightness. They are there  but we cannot see them. At night we are not facing the Sun  so that the part of the world that we are living in is not looking at the Sun and it is dark. We can therefore see the stars.

How did people find out electricity was travelling through the wires while experimenting with them?

Mo from 6K asked this question.

Mo, this is not a question that I am going to ask my friends to answer. I am myself, having difficulty in answering it. If there wasn’t this thing called electricity travelling from the battery to the bulb, the bulb would not light up.

What early experimenters would have found out was that electricity travelled best through metals. So what is special about metals? In 1897 (over two hundred years ago) a scientist called Thompson discovered a small particle called an ‘electron’ . It was found that all materials contain atoms, and atoms contain electrons but in metals some of the electrons are loosely attached to the atom. This allows the battery to push the loosely attached electrons from one metal atom to another thus delivering energy to the light bulb along the metal wire. For some thoughts on Energy go to Light and Energy

To test this create a circuit like the one below. Test different objects, like paper, rocks, plastic and the lead and wood in a pencil and the different metals, a coin, a bit of wire,  a paper clip ….. and find out if metals are really special.

croc clip diagraam

As you ask more questions and find out more answers to your questions, by observation and experiment, you will begin to fully understand the above answer to your excellent question.

DO NOT TRY TO DO THIS WITH MAINS ELECTRICITY. IT IS DANGEROUS.

Does this answer mean you need to ask a further question. Go to the Ask Another Question button below and ask it.

Asma (aged 9) asked – Why are materials only grouped as solids, liquids and gases?

Thank you for your question Asma. I asked my friends about it and this is what they said.

solidliquidgas

Some interesting comments from my team. I think you need to do some investigations of your own. Make your own set of groupings. What gases do you know of? air, steam,….. ?.  What different liquids do you know  of? water, oil, ……? What different solids do you know of? …. rock, wood, ….? Make a collection. Then look at your collection and see if some of the items do not fit into your grouping. Then ask why …then ask your question.

Tabia asks “Why do some circuits not work?”

Tabia, I asked my friends to help me with this question. They had some interesting thoughts.


short circuit

What my friends have done is to create something called a ‘Short Circuit’. Because the electricity has found a much easier path around the circuit it does not pass through the bulb (where it would have to do work). It takes the shortest route around the circuit. Try making some of these circuits in school. Instead of a light bulb use a motor or a buzzer (do you know their symbols?). Maybe put a switch in the circuit so you get rid of the short route. Have you another question? Why not go to

and ask it. You could also try the Circuits Quiz.

DO NOT DO ANY EXPERIMENTS  USING MAINS ELECTRICITY.

Also

DO NOT USE RECHARGEABLE BATTERIES FOR THESE EXPERIMENTS (The battery will get very hot)