Tag Archives: plants

Your Questions Answered!

As we have reached the end of the school year, here is a little round up of some of our favourite questions that children have asked us during STEM workshops.

1. Why doesn’t the energy ball give you an electric shock?

The energy ball is a little device we have that looks like a ping pong ball with two metal strips on top. Inside there is a light, a buzzer and a battery. If two people touch one metal strip each and then with their other hands touch each other, the ball lights up and buzzes. This works because we are conductors of electricity – electrons from the battery flow through us and back into the ball to complete the circuit.

The reason you don’t feel a shock when touching the energy ball because there isn’t enough electricity flowing through you to be able to feel it, and certainly not enough to harm you!

2. What do plants poo and wee? – St Wilfrids, Blyth

All living things have seven things in common – movement, respiration, sensitivity, growth, reproduction, excretion and nutrition. The sixth one, excretion, is a scientific word for producing waste. In humans, and many animals, that is our poo and our wee. They are the leftover waste products that our body doesn’t need so gets rid of.

Plants are living things, just like us, but you may have noticed they don’t poo or wee like we do. Rather than eat food like us, they make their own through photosynthesis. This produces a waste gas called oxygen which we breath in. Plants excrete oxygen rather than poo or wee.

3. Why does the moon control the sea? – Grange First School

Gravity is the force that keeps us close to the Earth, all really big things like planets and stars have a gravitational pull that attracts things near by. Because the moon is so big and so close to Earth it has quite a strong gravitational pull on our planet. The moon causes the water in the oceans facing it to pull towards it, resulting in a high tide. The pull of the sun’s gravity and the Earth’s own gravity also have an effect on the tides.

4. I’m the only one who can touch their nose with their tongue, is that because of my genes? – St Marys, Jarrow

Touching your nose with your tongue is known as Gorlin’s Sign. It is associated with a genetic disorder but not everyone that can do it has the disorder. About 10% of people without the disorder can touch their nose with their tongue and it does not appear to be due to genes you have inherited from your parents.

5. Why do we get goosebumps? – Billingham South Community School

We often get goosebumps when we’re cold, but they don’t do much to help us warm up, so why do we get them? Before we evolved to be modern humans, our ancestors were much hairier, we they got cold, getting goosebumps would cause their hairs to stand on end. As they had much more hair than us, they were able to trap a layer of air in the hair by doing this, providing them with extra insulation to keep them warm.

Although goosebumps are no longer helpful to us, we haven’t lost the trait through evolution because it doesn’t harm us. Therefore if a person was born with a mutation in their genes meaning they didn’t get goosebumps, they wouldn’t be at an advantage because of it so the non-goosebump genes wouldn’t necessarily be passed on more than the goosebump genes.

 

If you have any STEM related questions that you would like us to answer, just leave a comment in the box below!

#TryThisTuesday: Curly Fries!

Today we are looking at the science behind curly potato fries. First, let’s talk about how we make them.

  1. Carefully chop up a potato into straight thick chips.
  2. Boil around 250ml of water and stir salt into this water until no more salt will dissolve.
  3. Fill a bowl with tap water and place half of your chips into this bowl.
  4. When the salty water has cooled pour it into another bowl and add the rest of your chips to this.p1020750
  5. Leave both bowls of chips out overnight.
  6. The next day you should have one bowl of chips that are still hard and straight and the other bowl (with salty water in) will be full of chips that are more flexible, that you can shape into curls.

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The Science

The addition of salt to the water allows you to make curly fries due to osmosis. Osmosis is the movement of water from an area that has few molecules in the water to an area that has more molecules in it to try to even things out and create a balance.

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Plants like our potato here are made up of millions of cells that have a cell membrane around its edge which allows some things in and not others. Water can easily flow through this but the salt we dissolved in it can’t. Cells are filled with lots of little molecules so water usually flows into the cells and fills them to dilute the liquid. But when we have lots of salt in the water, there are more particles in the water outside of the potato cells than inside so the water leaves the cells.

waterout

bendyWhen cells are filled with water they are quite rigid and packed closely together making a fairly sturdy chip. When the cells are dehydrated, they are smaller leaving space between cells, allowing the chip to bend without snapping.

Osmosis is used in all plants – not just when you cut them up and put them in a bowl of water! Plants use osmosis in their roots to allow water to move from the soil into their roots.