Science can be used to answer huge questions like 'Are we alone in the universe?' and also some really silly ones like 'What's the perfect way to make a cup of tea?'
It doesn't really matter what the question you're trying to answer is - the important thing is how you try and get your answers. This guide will break down the Scientific Method into steps you can follow when you do an experiment.
Step 1 - Explore
Before we start our experiment we need to know what you're actually going to be able to do. Find a topic you're interested in. Think of a question you don't know the answer to. Find something that you don't know how it works. Do you have things in your home that could help you find out?
You might want to know what the best crisps are, for example.
Step 2 - Plan
To decide what we’re going to do with our experiment we need to find out a few things. Can you use a search engine to find out more? How have other people tried to answer questions like this? This section is a more in-depth look at the question you started to think about in the 'explore' section - start to add some details and get specific about what you want to find out.
In our 'crisps' example - which ones are the best is too vague. What does 'best' mean? Could you find out which packet has the lowest amount of salt and are healthier? This is something that you could get a real answer to.
Then we need to work out how we are going to find out – can you think of a way to test out your idea?
Step 3 - Predict
Before you do an experiment you should have an idea of what is going to happen. You can make predictions based on what you have set up. A technical type of prediction - a hypothesis - is like an answer you suggest to the research question you're asking. You can suggest exactly what you think might happen and have a way to test whether you were right at the end.
Again for 'which crisps are the saltiest?' you might predict that Ready Salted are actually the saltiest since that's the only flavour. Your hypothesis would be really specific about that and be something you can measure, such as - Hypothesis: Ready Salted crisps contain the most grams of salt per pack.
Step 4 - Test
We're going to need to test out your idea. This is where we say how we are going to find out the answers. What is the test you're going to do? How will you measure the results? What might the results mean?
Let's find out if you were right with the predictions you made! Do your experiment and observe everything that you can. Start to make some measurements. A good measurement is something that you can repeat and get the same results, that someone else could copy and understand, and tests just one thing at a time. If your measurement is testing lots of things at once - how do you know which one is giving you the result? If you eat 5 different flavours of crisps at the same time, how will you know which one is your favourite?
Step 5 - Research
Now that you've done your first tests you will know so much more than you did at the start. Did something surprise you? Did your experiment not work the way you had hoped? Here is where you can go back to searching for more information on how you might be able to do the experiment better or answer the question more completely.
Go back to the plan you made at the start and try to find out whether there were ideas and suggestions you missed the first time around. Research can be overwhelming - there's so much to take in, so there's a good chance that an idea was staring you right in the face before and you didn't spot it!
Step 6 - Improve
How can we get your test results to be even better than they were before? Can we get closer to a definitive answer to your first question? This section is about trying to do your experiment in the best possible way. Can we get the results to be more reliable? Can we improve the accuracy of your measurements? Do you just need more data to plot a better graph?
Step 7 - Review
What have you learned? What do your results tell you? If something didn't work, can you explain why it didn't work? If you've measured lots of things and you've plotted a graph - what does your graph tell you? What is the best way to share your new knowledge with other people?
Golden Rules of Good Science
Before you go out searching don't decide what you will find
Keep an open mind
It's okay to be wrong, the whole point is to find out something new, not to back up what you thought at first.
Examples
Okay - let's take those golden rules and the steps to good science and work through some questions. Pick a question you are interested in and we'll go through the steps.
Is there too much plastic in the ocean?
Let's work through the good science guide to find out how we might answer that question
Step 1 - Explore
You’re not likely to have an entire ocean in your home – so that’s probably out of the question. What you will need to think about is where do you come into the story of plastic ending up in the ocean. We don’t make the products but we use them and then throw them away. You can investigate your role in this story – think about where the plastic comes from, whether you have any in your home and explore the different places and things you do can make plastic waste that could end up going into the ocean.
You might want to know what the best crisps are, for example.
Step 2 - Plan
Is there too much plastic in the ocean? What do you think the answer to that might look like? Probably just a ‘yes’ or a ‘no’. The problem is that the question isn’t specific enough, you can’t measure anything related to it. We can make the question specific by adding in something we can measure:
How much packaging does a product really need?
Are there some materials that just can’t be recycled?
How much of the plastic in your house is recyclable?
How much of the recyclable plastic actually goes into the recycling?
Think about how you might answer those questions. We could find examples of plastic from as many places as possible – products from all the rooms of your house – and then see whether the packaging those materials came in is recyclable.
Step 3 - Predict
This is where we predict what the answer to a question would be. If the question we chose from the last section was ‘How much of the plastic in your house is recyclable?’ your hypothesis might be: All the plastic in my house is recyclable.
Step 4 - Test
The prediction is that all the plastic in the house is recyclable so we need to do two things – find examples of plastic from as many places as possible – products from all the rooms of your house – and then see whether the packaging those materials came in is recyclable. You can often find this information written on the side of the boxes that the materials came in but sometimes it’s trickier. In fact, if materials are too small, dirty, or dyed black they usually can’t be recycled regardless of what they’re made of!
By the end of your test you might have found some materials weren’t recyclable - this means that your hypothesis was wrong! Not all of the plastic is recyclable. This is okay though – being wrong and finding out why is a huge part of science!
Step 5 - Research
So we have a test result back in – now is the time to go back to the drawing board and find out a little more. There might be some materials that you couldn’t find out if they were recyclable or not. This is where looking up more information can come in. How can we get better answers to the questions you’re asking? For example, you might be thinking that putting the plastic in your recycling bin isn’t the end of the journey and wondering how much of the materials actually go on to be recycled in the end.
Step 6 - Improve
Repeat your test using the knowledge you’ve found out about whether the materials really do end up being recycled. Try and get a bit deeper into the information you have to turn it into a piece of work that you could share with someone and they would straight away know what you’re showing. Keep a log of what the materials are and whether they pass the ‘recyclable?’ test. You can then end up with a tally of ‘I found 32 different places that plastic comes from, and 19 of them were recyclable.’
Step 7 - Review
What do your results mean? You’ve found that some materials aren’t actually recyclable and not all plastic is the same. Is there a way that this information could be useful? Were some products more likely to contain single-use plastics? Were some rooms of the house better for recyclable materials? This is all useful information that you could share with people. Think about how you might tell someone else about what you’ve found out.
What's the strongest material?
Let's work through the good science guide to find out how we might answer that question
Step 1 - Explore
This part is the fun bit – go and find some examples of materials that you think are quite weak and some that might be quite strong. For all of the example questions, this section is probably the simplest. We are just looking for different materials. You can also think about shapes – are there different shaped things made of the same material that you can find?
Step 2 - Plan
What does strongest even mean? It could be a material that never bends, or it could be a material that can be stretched a lot without breaking. You’re going to find a lot of different properties for materials if you start to look them up! There’s hardness – can it be scratched or shaped? Is it ductile, malleable? Is it brittle?
You’re probably going to pick one property of the material that you can investigate with the items that you have found – and have a look into how engineers go about testing those things. Unfortunately engineers usually find out how strong something is by breaking it – and we don’t want to break anything useful or dangerous.
Two examples that you could really test:
How much weight can elastic bands hold before they snap?
How much weight can a piece of paper hold?
Step 3 - Predict
This is where we predict what the answer to a question would be. If the question we chose from the last section was ‘How much weight can a piece of paper hold?’ your hypothesis might be: Folding a piece of paper into a strong shape like a triangle will mean it can support more weight than a normal piece of paper.
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Step 4 - Test
Now to test the hypothesis. The prediction is that we can make a material like paper stronger by folding it into one shape. If you put the piece of paper across a gap between two piles of books, see how much weight you can put on top of the paper before it bends and collapses. Then fold the paper in half and see if it holds more weight. Try out some other ideas!
By the end of your test you might have found that the folded structure was much stronger - this means that your hypothesis was right! You can make the material stronger by changing its shape. Good scientists don’t just stop there though – now the question is exactly how much stronger can we make this?
Step 5 - Research
So we have a test result back in – now is the time to go back to the drawing board and find out a little more. Folding the paper in half doubled the thickness of the material and that made it stronger but you could also fold the material into certain shapes to see if the shape makes a difference to how strong it is. Architects make buildings with certain shapes to make sure they are strong enough to keep the roof up – can you find any ideas from them?
Step 6 - Improve
For example, you could fold the paper into a zig-zag shape by folding a thin strip, turning it over and folding it along that same thin strip (a concertina - it looks like this: /\/\/\/\) and then see if it can hold more weight. You’re now testing triangles! You could fold the paper really carefully to get square-shapes (like this |_|‾|_| ) To get some more data for your test see if you can make it even stronger by folding more, or fewer, times.
Keep a log of what shape you have folded into and how many times you folded it – then see if there is a pattern for how much weight they can hold. You can plot a graph of ‘maximum weight supported vs shape’ or ‘maximum weight supported vs number of folds’.
Step 7 - Review
What do your results mean? You’ve found that some shapes are stronger than others and the way you treat a material changes how strong it is. Is there a way that this information could be useful? Are the stronger shapes often used in buildings or in structures? This is all useful information that you could share with people. Think about how you might tell someone else about what you’ve found out.
How do cars keep us safe when they crash?
Let's work through the good science guide to find out how we might answer that question
Step 1 - Explore
So you’re obviously not going to be able to crash a car to test this. If we want to explore this question we are going to need to find a safe way to represent and test ideas out around cars and safety. In science, we often have to build a model system like this.
Fortunately, model cars are quite common so they will provide a good starting point for us. We also need to think about how we could simulate a car crash – do you have a ramp that the car could slide down into an object, for example?
Step 2 - Plan
We need to find out what cars actually do during a crash that keeps the passengers safe. The car crumples up and turns into a wrinkled wreck – this uses up the energy from the crash and the more energy that is used to bend the frame of the car and wrinkle the bumpers up into corrugated cardboard, the less energy is left for the passengers to get bent and wrinkled up too! Cars are designed so that the part that you are sat in is strong and solid to keep you safe while the rest of the car is designed to crumple up and absorb energy.
We can start to get specific about what we are going to test now – for example, we could make crash structures and attach them to a model car to see how it protects the car during the crash and test out:
Which materials absorb the crash the best?
What shape should the crash structure be?
Step 3 - Hypothesis
This is where we predict what the answer to a question would be. If the question we chose from the last section was ‘Which materials absorb the crash the best?’ your hypothesis might be: Soft materials will absorb crash impacts best and protect the passengers best.
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Step 4 - Test
Now to test the hypothesis. The prediction is that a softer material will absorb the crash the best. We need a way to test out just how much of the impact has been felt by the passengers! A good way to do this might be to use modelling clay to help balance an object like a small toy – an action figure or small teddy – on top of the car. Next, try to simulate some gentle crashes by rolling the car into something that won’t be damaged by the car – ask an adult if you’re not sure. See whether or not your object falls off the car. Without a crash structure to help, should fall off. Take some of the modelling clay away until it does. Now take a material that you think could help to absorb the crash impact – maybe a piece of paper or a piece of sponge and attach it to the front of the car. Repeat the crash tests and see whether the passenger falls off the car with each crash structure in place!
By the end of your test you might have found that softer materials protected your passenger best - this means that your hypothesis was right!
Step 5 - Research
So we have a test result back in – now is the time to go back to the drawing board and find out a little more. You’ve found that soft materials keep passengers safe but do you want a massive piece of sponge attached to the front of your car? How do engineers actually make the crash structures out of the kinds of materials we expect to see on cars like steel?
Step 6 - Improve
You could take paper and see if you can fold it into a shape that looks like a bumper – for example a paper tube. See whether different sized tubes – or how many times you roll the paper around the tube – have different abilities at protecting your passenger in a crash!
Keep a log of what shape you have folded into and see if there is a pattern for whether the passenger was knocked off your car. You’ll have to repeat the experiment several times to be sure that they work. Maybe the structure doesn’t always keep the passenger safe! Try and find the shape that is most likely to protect the passenger. What percentage of crashes were ‘safe’ and ‘unsafe’ for each shape of bumper?
Step 7 - Reflect
What do your results mean? You’ve found that some shapes are stronger than others and the way you treat a material changes how strong it is. Is there a way that this information could be useful? This is all useful information that you could share with people. Think about how you might tell someone else about what you’ve found out.
How long will my phone battery last?
Let's work through the good science guide to find out how we might answer that question
Step 1 - Explore
Batteries are really complicated things. They contain a lot of different materials all mixed together and – as with anything that can store a lot of energy – they can be quite dangerous if they aren’t treated carefully! Our experiments can never take the battery outside of the normal usage that is recommended by the manufacturer (like using a phone battery only in a phone and using the recommended charger, for example) to be safe. We probably won’t need to do to too much exploring for this one!
Step 2 - Research
Instead of exploring to find lots of materials to test then, we can research how batteries work and which properties we can test. You could look up details on battery safety or tips for how to get the most out of your battery lifespan with a ‘battery management system’. You could even look into the structure of a battery, and what happens to the chemicals inside when it is charged and discharged. We could look into how you might get your battery to last for years without losing any capacity, but we don’t really want to wait for years! If our original thought was ‘how long will my battery last?’ then to get a bit more specific we could ask:
Does the first 10% of battery charge last as long as the last 10%?
Do some things drain the battery faster than others?
Step 3 - Predict
This is where we predict what the answer to a question would be. If the question we chose from the last section was ‘Does the first 10% of battery charge last as long as the last 10%?’ your hypothesis might be: Each 10% of battery charge should last for the same amount of time, so long as the phone is using the same apps throughout.
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Step 4 - Test
Now to test the hypothesis. The prediction is that each 10% of battery charge should last the same amount of time. You could check your battery every 10 minutes or so and write down the percentage that is left and make a graph. We need to see how many minutes it takes for the battery to go from 100-90%, then 90-80%, etc.
By the end of your test you might have found that the battery drains at the same speed throughout the charge – or you might have found that the last 30% takes a long time to drain! Does this means that your hypothesis was right or wrong?
Step 5 - Research
So we have a test result back in – now is the time to go back to the drawing board and find out a little more. Your phone battery will have a battery management system that controls how much power your phone can use at any time – this probably means that when the battery power is 95% the phone runs much more quickly than it does at 5% power when it’s trying to save power!
Step 6 - Improve
If the battery management system is changing our results, we could look at turning that system off in your phone settings to repeat the tests – but be very careful when changing any settings and always ask for permission first, it’s best not to change a setting if you’re unsure and it’s always wise to remember exactly how you did it so you can reset it afterwards!
We could also look at the rate that the battery is being used depending on which apps are open – we could measure the battery percentage every minute and then plot ‘battery percentage’ versus ‘time’ on a graph and work out ‘battery percentage used per minute’ for a few different apps. Try the phone on standby versus a video app, for example. The initial question ‘how long will my battery last?’ has become more complicated as we have learned about the structure of the battery, the battery management system and the apps that the phone runs using different amounts of power!
Step 7 - Review
What do your results mean? You’ve found that the battery management system helps to keep your battery (and you!) safe and working for as long as possible. Is there a way that this information could be useful? This is all useful information that you could share with people. Think about how you might tell someone else about what you’ve found out.
