# Elizabeth (9) asks “How does sand form in a desert?”

I agree we need to do an investigation.  The suggestion is that the desert sand might have come from the soil. Let’s see if we can find sand in the soil around us. Before we do this lets think about soil, the soil in your garden. What do you think it is made of? Maybe it is just made of soil? Maybe it is made of a mixture of things? Let’s investigate these questions.

Collect some soil. Get a plastic transparent beaker or a jar with a lid. Put a couple of small spoonfuls of your soil into the container. Add enough water so that it is half full. Cover and shake for about 20 seconds. Put it down and wait for about fifteen minutes. Now look at it and make notes on what you see. Repeat with another sample and another beaker or container (investigations always need to be checked).

Has your experiment resulted in layers of stuff in the beaker? Maybe a bit like the layers in the image below.

If it has then think about why you have layers? What has formed the first layer and why? Was it because it was the lightest or heaviest ‘stuff ‘ in the jar (soil)? Is the second layer made up of ‘stuff’ that is lighter or heavier?

The bottom layer is ‘sand’ …..the heaviest ‘stuff’ that makes up soil. The other layers are ‘silt’ and ‘clay’. Look at the diagram that my friends have given you the sand particles are the biggest.

Now to deserts. In very arid (dry) conditions the soil dries out. The wind basically blows away the smallest particles of clay and silt leaving the largest so a desert of sand is formed.

Elizabeth … thank you for your question.

# Abdul (10) asked “Why do heavy things fall faster than light things?

Abdul, a great question. I can remember asking this question to a class of 9yr olds. Our investigations started by dropping a sheet of A4 paper and timing how quickly it reached the floor. We had to make the test fair and then recorded our answers. We then all screwed up our piece of A4 paper and then predicted how long it would take to drop the same distance, again making sure the test was fair.

Several in the class said that the results of the test was unfair, because the sheet of paper had been made heavier. A mass balance proved that was not the case. So why had the screwed up ball of paper fallen faster? Your thoughts please.

So how can we test if heavier things fall faster than light things? Is it true or not true? What things do we need to change and what things do we need to make sure are the same. We need a fair test. Let me know your answers.

# “Does sound bounce?” asked Molly (7)

Molly, this seems to be a question that we could investigate. I have asked my team about it.

You will now have to think of some experiment to test the ideas that my friends have come up with. See if you can get a plastic mirror and maybe a sheet of cardboard. The next task is how to see if you get a bounce. You will probably need a friend , a cardboard tube and a device to make a sound (bell, buzzer, horn or something else). Your friend can ring the bell in front of the tube and you can  then listen to see if you can hear a bounce from the mirror or cardboard. Try it and then try it again, see if you can make the test as fair as possible. If you can get it to work, try with other surfaces, paper, carpet, aluminium foil. Have fun.

Let me know how it went.

# “Why doesn’t America use the metric system?” was Dekekisha’s (11) question.

Dekekisha, what a question.  Something that I have always asked myself when I have been converting Centigrade readings to Fahrenheit so that I could understand the weather. Friends, help me.

It is one of those occasions when I agree with you. As long as we all know and understand the different measurement systems and can confidently convert one to another.

Disagree, then let me know by clicking on the Reply button below. Thank you team.