Category Archives: science education

Fun experiment: What does gravity do to us?

It was one of these rainy days that we always get in the summer half-term. Our bike ride had just been cancelled due to the bad weather. Disappointed we started talking about alternative plans. Unsurprisingly, one thing led to another and we ended up talking about space travel. My daughter would not like to go to Jupiter because it is made of gas, and how could we live there? My son said that he would quite like to live on the Moon, because he “would be jumping all day long and that would be fun, wouldn’t it be mum?”

It was that comment that sparked a lively discussion about gravity and what it does to us.

Earth’s gravity is the force that holds us to the planet. Without it we would fly off. Gravity depends on the mass. Because the Earth is more massive than the Moon, Earth’s gravity is bigger than the Moon’s so the pull is stronger for any object on our planet than it would be on the Moon. For instance, if you can jump 20 cm on Earth, you could jump nearly 2 m on the Moon. Wouldn’t that be fun?

But how does gravity affect us?

Here is a nice little experiment to help us investigate.

Hypothesis

Gravity is pulling us down, as a result we are slightly shorter in the evening than in the morning when we have spent the whole night lying in the bed.

Method of exploring the question

Measure height just before we go to bed and just after we get up.

Subjects

Child 1 – 9 years old

Child 2 – 6 years old

Data recording

The children designed a table to record the measurements. They had to think about what the question is what the best way is to sort out the data.

Measurements

gravity experiment

Discussion

Hurray!!! We have shown that indeed gravity makes us shorter. We would be probably a little bit taller if we were living on the Moon. We used a simple measuring tape, hence the measurements are not accurate, but fluctuate a couple of centimetres. However there is a clear trend, which shows that the children are slightly taller by 2 – 3 cm in the morning.

Magnetic money

I often overhear  the children talking about their day at school. So I know that the last few weeks both of them have been enjoying their science lessons. D in Y4 has been learning about forces, while P in Y1 has been investigating the properties of materials. The common theme between the two topics is magnetism, so a couple of days ago I grabbed the opportunity and asked the children to help me with a “Magnetic Money” investigation.

This is what it is all about: Children investigate the magnetic properties of 1p and 2p coins. It is not as straightforward as it may sound, because as they are going to find out soon some coins can be magnetic, while others are not. This does not depend on the value. So they need to solve the mystery. When is a 2p coin magnetic?

For this activity you are going to need:

1p, 2p coins (make sure that you have a mixture of old and new coins)

Fridge magnet

Sheet of paper to record your findings

Hint: In 1992 the composition of 1p and 2p coins was changed from bronze to copper-plated steel. As a result coins produced after 1992 are magnetic. Older coins are not.

Here is a “transcript” of the discussion I had with my daughter.

Me: Are these coins magnetic? Let’s find out.

D tried a 2p coin. The coin was attracted by the magnet.

D: Oh this is magnetic.

Me: Do you think that all coins are magnetic?

D: Yes. My hypothesis is that all coins are magnetic!

So she tried another 2p coin and to her surprise this time it was not attracted by the magnet.

D: Oh this is so strange. This coin is not magnetic…

Me: Why do you think that this coin is not magnetic?

D: Because it does not stick to the magnet

Me: Why is that? Does it mean that the two coins are different?

D: They look the same to me.

She put one on top of the other. She points that the two coins have the same diameter.

Me: What about their thickness?

D: Oh, one of them is slightly thicker. Is this the magnetic one?

Me: What about the weight?

She balanced the two coins on the tip of her two middle fingers

D: They feel the same.

All this time P is playing with his magnet and coins and is shorting out magnetic and non-magnetic coins in two piles. He does not look interested in our investigation but he is obviously intrigued by the way the investigation is going. So he decides to intervene. In fact, they just had talked about magnetism the previous day at school, so he had something really useful insight to add to the discussion.

P: I know why! They are made from different materials.

D: Well done P! That could explain everything.

Me: What do you think you could do next?

D. I will try all other coins and sort them out.

So she tries all 1p and 2p coins and end ups with four piles of coins.

Me: How can we predict if a coin is magnetic or not?

D:That’s tricky, because we can not tell what material is made from just by looking at it.

She was really puzzled and could not come up with any ideas

Me: Look at the dates on the coin. What do you notice?

She records the dates of the coins in a table.

D: All the magnetic coins have dates after 2000. There is only one made in 1999. The non magnetic coins are really old.

She looks at one coin dated 1971.

D: Cool! This is  older than you.

Next I gave her a new pile of 1p and 2p coins.

Me: I want you to sort this out for me please. But there is a catch, you are now allowed to use a magnet this time. I want you to predict which coins are magnetic.

D: That’s easy-peasy mum. I only have to look at the year they were made.

She checked the dates and then uses the magnet to confirm her findings.

This is such a simple activity but D really enjoyed it so much that she plans to demonstrate it in her next science class.

Throughout this investigation D recorded her finding in a table with three columns

Value – Year – Magnetic?

When trying this at home encourage your child to use appropriate vocabulary such as Hypothesis Prediction, Investigation

On inspiring children

Yesterday I attended my first ever TEDx event at the University of Warwick. The TEDxWarwickEd talks were dedicated to inspiring education initiatives and learning approaches. The common theme that ran through the five presentations was creating inspiring educational environments that cater for the individual learner – this is a huge endeavour and the five speakers presented their thoughts, vision and their innovative ventures on the theme.

As the TED events are all about ideas worth spreading, what I took with me and what I want to share with you is an idea from the presentation of Daniel Scully, PhD candidate in Particle Physics at the University of Warwick and science communicator. His talk explored how we can attract more young people to study science. There is a worrying decline on the number of students taking A level physics. In response to that there are a series of national initiatives aiming to encourage students and in particular female students to take up physics.

So how do we inspire children to study physics? Here is an idea worth spreading in two quotes “… it is not the questions we have answered but what needs to be answered – it is what lies ahead that is important” and “People are not inspired by what you have done, they inspired by what THEY CAN DO.” In other words, science is not about what we have achieved, but more importantly about what we haven’t. This is where the excitement, innovation and rewards lie. So let us sow the seeds of curiosity and hopefully they will grow into a love for exploration and discovery.