Our #TryThisTuesday this week, is a challenge for you. The task is to fill a dry bottle with rice and lift it up using only a pencil.
Have a go or challenge your friends, once you think you’ve cracked it (or given up) scroll down to see how we did it!
Take the lid off the bottle and push the pencil half way into the rice. Take the pencil out again and push it back in, repeat this about 10 times. Eventually, when you pull the pencil to take it out, the bottle will lift up with it!
This occurs due to the force of friction acting on the pencil and holding it in place. When you first pour the rice into the bottle, it will arrange itself with lots of gaps but every time you insert the pencil you push the rice down making it more compact or dense. Some grains may even break or change shape under impact with your pencil. The more you do this, the greater the surface area of rice that comes into contact with the pencil. This gives a greater force of friction. Friction is a force of resistance between two objects when they move past each other. The force is so strong at this point that it doesn’t allow the pencil to slip past the rice and so the rice (and the bottle) moves with the pencil as you lift it.
In the Real World…
This works in a similar way to quicksand. If you were to step onto quicksand, you would compact the particles, making them move closer together and lock around your foot, pulling you in. The friction makes it difficult for you to pull your foot out. Don’t worry too much though – quicksand is much denser than a human being so you wouldn’t be able to completely sink in it. As we learnt from our ketchup packet submarine and the oil and water experiment – less dense substances float above denser substances so you would stay above the surface of quicksand!
It’s the planet that we live on and home to 7 billion people as well as billions of plants and animals. But with climate change and other issues such as pollution, we need to do more to look after our home. Earth Day gives the opportunity to come together and work toward a greener future, showing support for the environment.
Why is it important?
Humans are using resources at an alarmingly fast rate, currently using more resources than the Earth can produce. Today humans use 1.5 planets’ worth of resources every year!
Climate change is a huge problem for the future of our planet. It will lead to things like increased sea level and flooding, drought, and a rise in temperature. This will make it more difficult for plants and animals to survive and hence humans. Scientists agree that we can reduce the impacts of climate change, but we need to act as fast as we can.
There are lots of other environmental issues such as deforestation, pollution and ocean acidification that are affecting the environment. These problems can lead to a loss in the number of animal and plant species causing the Earth to have reduced biodiversity (the number of species). Lots of plants and animals are interlinked in food chains, so losing one can have a knock on effect on other species. Biodiversity is vital to our survival, for supporting the ecosystem, finding things like new medicines and for providing humans with lots of raw materials.
How can we help?
There are lots of things we can do to reduce our footprint on the Earth. These are just some things you could try and do:
- Shop for locally sourced produce
- Eat food that is in season
- Eat less meat
- Bring your own shopping bags
- Use a reusable water bottle rather than bottled water
- Don’t drive if there is an alternative
- Take holidays closer to home
- Use energy saving lights
- Unplug your electronics when not in use
- Plant a tree
- Use a reusable coffee cup
Happy Valentine’s Day! Love can confuse your brain, and so does this week’s Try This Tuesday.
You don’t need any equipment to try this experiment at home – you just need to stare at your screen, or more specifically the + in the middle of the picture below. You can blink but don’t look away.
If you stare long enough the pink dots should disappear!
It looks like the pink dots have disappeared due to a visual phenomenon called Troxler’s fading or Troxler’s effect. if you fix your eyes on a certain point, then anything in your peripheral vision will fade away and disappear after about 20 seconds. In this experiment our sight was focused on the + in the middle of the screen and the the pink dots in your periphery slowly fade and finally disappear. It works especially well in this experiment at there is such low contrast between the light pink dots and the grey background.
This is a type of optical illusion. If you want to see another, have a look at our spinning disk Try This Tuesday.
This week we’ve been helping out with the Engineering Education Scheme. Lots of year 12 students from the local area have been working with industry to come up with a project based on real scientific, engineering and technological problems. The students have come in and had a chance to work in the engineering laboratories and workshops that university students and researchers would use. After lots of problem solving and hard work, they presented what they had done so far. These are just a selection of some of the projects.
Mechanical Engineering – Lifting
This group was working on creating a lifting mechanism for a heavy item/box. The current method of lifting isn’t very good as its centre of gravity is in the middle so it wobbles when they lift it. They created a design with a cradle for the box which spreads out the centre of gravity. It is more stable and quicker to lift, saving the company time. The use of shackles mean the box can attached by hand, no tools are needed, again saving time.
Mechanical Engineering – Shield
A mechanical engineering group created an extendable shield. This is important for keeping people safe in war. In general all shields appeared to be really big or small, but there were none that could adapt to the situation. Use of cogs allowed the shield to be extended or retracted, solving the problem.
Electrical and Civil Engineering – Solar Power
The brief from WSP Global was to provide renewable energy through use of solar panels to the 350 people who work in the office. The students made a to scale model of the office based on blueprints and used a fixed angle light (as the sun) to look at the shading on the roof of the building. They also ran computer simulations to look at which areas would capture the most sun.
Civil Engineering – Leisure Centre
The brief was to design a leisure centre on land near to St James Football Park. There were lots of problems to be overcome in the design. The centre was to be built on top of an old mine shaft, which might mean the building would fall into the ground. They calculated that it was too expensive to fill the land underneath with concrete, so calculations had to be made for how heavy each part of the leisure centre would be.
Marine Engineering – Underwater vehicles
This marine engineering group was helped by engineers from BAE systems. They looked at making an underwater unmanned vehicle. They had to do some problem solving with getting the submarine to sink, working out the exact amount of weight required to make it neutrally buoyant. They used electromagnets to power the vehicle.
Marine Engineering – Underwater pipes
This group worked with GE oil and gas looking at using flexible pipes underneath the seabed. They compared two different materials; thermoplastic and thermoset. They did lots of tests, looking at things such as compression (squashing) and torsion (twisting) to find out its properties. They also looked at factors such as the price. Testing found that it was really important that there were no faults in the thermoplastic as it broke a lot easier. Underwater pipes are really important for transporting things like oil and gas.
You’ve probably got exams coming up, maybe you’re supposed to be revising now, chances are you’re surrounded by textbooks. If so here is a quick little experiment you can try.
All you need is two large books with lots of pages, around 200 or so.
Start by interleaving the pages one on top of the other to sandwich the books together, like so:
This doesn’t require any kind of glue or tape but the two books should now be securely stuck together. Challenge your friends to try to pull the books apart – no matter how strong they are, they won’t be able to do it!
So if there’s no glue, why is this? It’s all because of friction. Friction is a force that occurs when one object moves over another – it is the resistance that is felt. When you try to pull the books apart there is friction acting on each page opposing the movement. If you consider there are over 200 pages, this force is multiplied and so becomes super strong!
When you pull the books the pulling motion squishes the pages in the middle with a greater force, this in turn makes the force of friction greater as it acts to oppose this force. So the harder you pull, the more difficult it is to separate the books!
Your challenge this week is to pierce a skewer through a balloon without popping it.
Share your attempts with us on Facebook, Instagram or Twitter – just use the hashtag #TryThisTuesday
How we did it:
Pierce the balloon at the bottom near the knot, then slowly pass the skewer through and piece it through the darkest part at the far end. These points are where the rubber is under the least stress so is less likely to tear and pop under impact.
Did you manage it?