Teaching Strategies, Tactics, and Methods

The cell is the basic unit of structure and function in all organisms. Cells are the microscopic building blocks of life.

Everything in the human body is made up of cells. Our cells group together to make tissues, and these group to make things like our skin and individual organs.

Organelles are structures within human cells that carry out specific tasks to help the cell. If you opened up an object with many components inside of it, like a mobile phone, you would see that the different things inside it support the overall function of the phone. For example, there is a battery to power it, a screen, and speakers: together, they make up the phone and its different functions, and that is how the organelles operate within a cell. They each provide an additional process that allows the cells to work. Look at this diagram showing the placement of organelles within an animal cell; you can see ribosomes, lysosomes, the nucleus, and mitochondria.

What are the types of cells in the human body?

All cells are identical at the start of their lives called stem cells. Then, they become differentiated depending on what organism they are in – plant or animal – and what specific job they need to do. This means that they change to perform a particular function better. These are called specialized cells, and there are many different types of these cells in the human body.

In number, there are trillions of cells in the human body, and they are all different types, depending on where they are in the body and the job they must do. There are hundreds of different types of cells working in the human body, some of the most common include:

The nerve cell

Nerve cells make up the human nervous system – they are also known as neurons. They allow the brain to communicate with organs like the brain using nerve impulses. There are three types of nerve cells: sensory neurons, relay neurons, and motor neurons.

The red blood cell

Red blood cells carry oxygen and carbon dioxide around our bodies in our bloodstream. The cell membrane of a red blood cell allows oxygen and carbon dioxide to attach to the hemoglobin molecule inside.

The white blood cell

White blood cells protect our bodies against pathogens (these cause disease) by building up our immune system and attacking things that might make us sick.

The Muscle cell

Muscle cells are what make up the muscle tissue in our bodies. Different types of muscle cells protect and support our muscle fibers, allowing us to move our bones using our muscles; and allowing parts of our bodies to move all by themselves as our organs carry out their functions.

Ciliated Cells

These line up together to make the walls or linings of our organs. They protect the human body from disease and infection.

Skin cells

Our skin is made up of different types of cells. Some of these are called epithelial cells. They protect what’s inside the human body from the outside world, keeping it clean, sterile, and free from foreign objects that could damage organs. Our skin also stops this inside of the human body from becoming dehydrated and produces vital vitamins.

What are volcanoes (for kids)?

The word ‘volcano’ comes from the island ‘Vulcano,’ a volcanic island in Italy. The island gets its nickname from the Roman god of fire – Vulcan. Roman mythology says that Vulcan lived in a volcano, and if the Romans made him angry, the volcanoes would erupt.

So, what exactly is a volcano? A volcano is a type of mountain that caves downwards to a pool of molten rock below the Earth’s surface. During a volcanic eruption, pressure builds up underground due to the formation of magma, molten rock mixed with gas. The pressure causes gases and rock to shoot up through the opening and spill over with lava fragments. Volcanic eruptions have triggered tsunamis, floods, and earthquakes

Volcanoes for Kids: How are volcanoes formed?

To fully answer the question, ‘how are volcanoes formed?’, we need to discuss tectonic plates.

Most of the Earth’s volcanoes are located along tectonic plates because, when tectonic plates collide, one tectonic plate will slide and move under another one, forming a volcano. Usually, it’s a thinner oceanic plate that moves under a larger continental plate. The water trapped in the process will start to boil (due to the high temperatures) and melt the rock. This melted rock is magma.

Volcanoes are formed when magma, which is located at the center of the Earth, pushes its way upwards through the Earth through a long shaft. When the magma travels through the Earth’s crust, it emerges as lava. Once this lava has erupted onto the Earth’s surface, it cools and hardens into a rock pile.

Many volcanoes are mountains as a result of this process. Indeed, the highest mountain in the world, Mauna Loa, is a volcano that extends for thousands of meters underwater. This is a shield volcano, meaning it erupts slowly over a long period.

Sometimes volcanoes build up pressure as the magma emerging from inside the Earth pushes upwards, and this can cause volcanoes to explode with great force. These volcanoes are called composite volcanoes.

Examples of these kinds of volcanoes include Mount Vesuvius, which erupted in 79AD and destroyed several settlements, including Pompeii, and Mount St. Helens, which erupted in 1980 and destroyed 200 homes.

After the eruption of these two volcanoes, the large chamber inside the mountain that once held the magma collapsed and formed a crater known as a caldera.

Different Types of Volcanoes

Scientists have created three main categories for volcanoes: active, dormant, and extinct.

• Active volcanoes – An active volcano has erupted recently, and there is a possibility that it may erupt again.
• Dormant volcanoes – A dormant volcano has not erupted for a long time; however, it may still erupt in the future.
• Extinct volcanoes – An extinct volcano erupted thousands of years ago and will probably never erupt again.

Different Parts of a Volcano

Did you know there are different parts to a volcano? Six pieces! They are called:

• Eruption Cloud – A cloud of ash that is formed by volcanic explosions.
• Vent – An opening in the surface of the Earth through which volcanic materials, such as magma, can escape.
• Crater – The mouth of a volcano that surrounds the vent.
• Throat – The entrance of a volcano that ejects lava and volcanic ash.
• Conduit – An underground passage which magma travels through.
• Magma Chamber – A large underground pool of liquid rock found beneath the surface of the Earth.

How many volcanoes are there in the world?

For several reasons, it is unknown exactly how many volcanoes there are in the world. One of these reasons is that different people’s definitions of a volcano can vary. For example, volcanic fields comprise hundreds of individual eruption centers, including cinder cones and shield volcanoes. These individual eruption centers are all linked to the same magma chamber and may be considered one single volcano by some people.

It’s estimated that there are around 1,500 potentially active volcanoes worldwide. This figure excludes the continuous belts of volcanoes on the ocean floor at spreading centers such as the Mid-Atlantic Ridge. Out of these 1,500 volcanoes, about 500 of them have previously erupted, and many are located along the Pacific Rime, also known as the Ring of Fire (some people place this figure closer to 600). Each year alone, about 50-70 volcanoes erupt around the world. In addition, scientists have found an average of around 20 volcanoes emit at any given time.

Why do volcanoes erupt?

Volcanic eruptions center around the movement of tectonic plates, which are large sections of the Earth’s crust. These plates shift around, either towards one another, away from one another, or alongside another, and this movement triggers a volcanic eruption.

Earthquakes can also happen as a result of tectonic plates moving around. When earthquakes happen, small tears, called fissures, appear in the Earth’s crust. These fissures allow the magma beneath the surface of the Earth to escape.

What happens when a volcano erupts?

There is no standard answer to what happens when a volcano erupts. Volcanic eruptions will differ depending on the type of volcano and what types of tectonic plates it sits on.

Composite Volcanoes

Composite volcanoes occur at destructive boundaries, where tectonic plates move toward one another. Inside these types of volcanoes, the lava is super thick and sticky, which makes them explosive when they erupt. Composite volcanoes also tend to release a ton of hot ash and rocks into the air when they explode, which is very dangerous.

Shield Volcanoes

Unlike composite volcanoes, shield volcanoes occur at constructive tectonic boundaries, where the tectonic plates move away from one another. Inside these types of volcanoes, the lava is thin and runny. This type of lava can travel long distances in a short period once a shield volcano erupts.

Cinder Cones

Cinder cones are circular or oval cones. They are made up of small fragments of lava blown into the air through a single vent. When they cool down, they form rocks around the vent. They grow quickly but aren’t usually very big or dangerous.

What happens when a volcano erupts? – The Aftermath

We know what happens when a volcano erupts, but what are the consequences for the surrounding area? Volcanic eruptions are dangerous, so people nearby usually flee the room quickly. The land itself cannot escape, however.

When the burning hot lava is released in the eruption spreads across the land nearby, it can seriously damage entire towns, houses, and farmland areas. The lava isn’t the only issue, as the volcanic ash can seriously affect anyone nearby. Anyone that breathes in the ash can suffer from breathing problems. Moreover, this ash halts air travel, as it is unsafe for pilots to fly in such low visibility.

You might be tempted to think volcanic eruptions have strictly negative effects, but this is not true. On the contrary, volcanic eruptions positively impact the surrounding area. For instance, any lava and ash that is not too thick can break down over time to create fertile land for farming. In addition, the heat from volcanic eruptions can also be harnessed and used to make electricity.

Which country has the most volcanoes?

Volcanoes are located worldwide, largely in places where tectonic plates either converge or diverge.

If you’re on the hunt for volcanoes, the Mid-Atlantic Ridge is the place to go, as it is home to many volcanoes. Another place brimming with volcanic activity is the Pacific Ring of Fire.

Volcanoes form in regions where the plates on the crust are thinning or stretching out. The East African and Rio Grande Rift in North America are examples of these regions.

Regarding which country has the most volcanoes, the answer is the United States, closely followed by Russia and Indonesia.

Volcanoes in the United States

The United States is the country that has the most volcanoes in the world, with a total of 173. The majority of the volcanoes in the US are located in Alaska, where there are volcanic eruptions every year.

Hawaii is home to Kilauea, the most dangerous volcano in the United States. Kilauea is the most active volcano in the world that has erupted continuously since 1983.

While the United States contains 173 volcanoes, not all are active. There are 161 active volcanoes in the US, most of which are located on the country’s western side. Eighteen of these active volcanoes have been officially labeled a high threat due to their internal activity and proximity to large populations. Out of these 18 volcanoes, five of them can be found in Alaska.

Volcanoes in Russia

While Russia is not the country with the most volcanoes in the world, it does come in at a close second.

There are 166 volcanoes in Russia. Most of Russia’s volcanoes are along the Kamchatka Peninsula, on the eastern side. Along the Kamchatka Peninsula alone, there are 29 active volcanoes.

The highest volcanic mountain along this peninsula is called Klyuchevskaya Sopka, which is a stratovolcano. Klyuchevskaya Sopka towers at a whopping 15,584 feet (4.75 km) above sea level, making it the highest active volcano in Eurasia and the largest active volcano in the Northern Hemisphere.

Volcanoes in Indonesia

Indonesia is number 3 for the country with the most volcanoes in the world.

There are around 139 volcanoes in Indonesia, all of which are part of the famous Pacific Ring of Fire. The most active volcanoes in Indonesia are Mount Merapi and Kelut, both found on Java island. The majority of the volcanoes in Indonesia are located along a 1,800-mile-long chain called Sunda Arc.

The environment and population of Indonesia have suffered greatly in the past due to its high levels of volcanic activity. The largest eruptions in the world have taken place in Indonesia.

The biggest eruption in history came in 1815 from Mount Tambora in Indonesia. This eruption had catastrophic effects on the climate across Europe in 1816 and is looked back on as the year without a summer.

Selective breeding is when humans choose which animals or plants breed together. There are many reasons for this, ranging from useful to attractive.

Since the beginning of agriculture, farmers have been aware that breeding certain individuals will bring about desirable offspring. This is why we have crops that provide high food yields and different breeds of animals like dogs.

However, Gregor Mendel’s pea plant experiments carried out between 1856 and 1863, provided the foundation for our understanding of the scientific laws of inheritance. Mendel selectively bred pea plants to understand how different traits were passed onto offspring. These studies inform modern-day theories in selective breeding and genetics.

How does selective breeding differ from natural selection?

At a similar time to Mendel’s pea experiments, Charles Darwin and Alfred Russell Wallace presented their theory of evolution. Darwin discussed the process of selective breeding and how it has produced a change in species over time in his book On the Origin of Species, published in 1859.

• Darwin bred pigeons and selected mating pairs to generate certain traits in their offspring.
• Understanding selective breeding helped Darwin to formulate the theory of natural selection.
• Selection occurs in nature because the organisms better adapted to the environment are more likely to survive and reproduce.

What is the process of selective breeding?

1. Choose the plants or animals from your existing stock that have the desired feature.
2. Breed these with each other.
3. Choose the best of the offspring and breed these together.
4. Continue this process over several generations; eventually, all the offspring have the features you are looking for.

What are some examples of selective breeding in plants?

People have selected certain traits from the original brassica plant to create different foods we can eat. From kohlrabi to cauliflower, broccoli to kale, these tasty vegetables are all the outcome of selective breeding in plants.

Corn is a vital crop in many parts of the world. Selection of corn has been taking place for over 10.000 years! Yield has been increased by selecting more kernels. There are also varieties of corn that can survive in harsh climates, which is important in our changing world.

What are the benefits of selective breeding in plants?

Selective breeding can create new varieties of good crops. They may be bred for the following characteristics:

• Higher resistance to pests and disease – for instance, selective breeding can limit the number of crops that perish due to blight.
• Higher yield.
• Shorter time before harvest. More harvests mean more produce in a shorter amount of time.
• To allow plants to grow on lands not previously suitable for farming. For example, land can be unsuitable due to poor soil fertility.
• Selective breeding can increase the protein in crops which can help improve food production worldwide.

What are some problems with selective breeding?

The problem with selective breeding is a lack of variation. Selective breeding reduces the number of alleles (genetic differences) in a population. This leaves a population vulnerable to sudden changes in the environment and disease.

What are some problems with selective breeding in plants?

Crop Case Study: the banana

• Today’s bananas are a cultivar (type) called the Cavendish. Until the 1950s, however, the main variety of bananas grown was the Gros Michel, ‘Big Mike’ banana.
• Gros Michel bananas had thick peel and dense bunches, which made the banana easy to export and less prone to bruising.
• A fungal disease wiped out vast plantations of Gros Michel bananas in Central America in the 1950s, causing the swap to the Cavendish.
• In monoculture farming (fields planted with one type of crop), if one plant gets infected, the rest will likely also become infected.

Cavendish bananas are also susceptible to fungus, and the same could happen again. The spread of a fungus to other continents could have a globally devastating effect on the supply of this important crop.

The impact of climate change is leading to more extreme weather events, impacting pollinators, and shifting harvest times – or no harvest at all.

What is an example of selective breeding in animals?

Dogs

Based on the evidence, scientists agree that dogs were the first animal to be domesticated by humans. However, domesticated dogs have lived beside humans for at least 14,200 years – perhaps even longer!

Dogs have been selectively bred for their traits for centuries. This may include a dog being larger, smaller, stronger, or having a different fur color, depending on their environment and what they do with the people who care for them. This can benefit humans and dogs – for instance, if the dog has thick fur and lives in a cold place.

A pedigree dog is a puppy bred from parents of the same breed. Their parents will have been the same breed, and so on, back through the dogs’ genetic history. This lineage can be proven by registration with ‘The Pedigree Club,’ which records pedigree dogs in the country.

Selective breeding can lead to inbreeding. This is where animals have been mated with close relatives. This results in little variation in a population. As a result, the animals are more likely to have health problems caused by their genes or be more susceptible to certain diseases.

Breeds like French bulldogs and pugs, bred for squashed faces, suffer from breathing difficulties, eye ulcers, skin disorders, and other illnesses. Some problems are less obvious: bigger dogs like Labradors now have health problems because they have been bred to be larger, taller, and stronger. As a result, they may have joint issues and are more susceptible to cancer.

Centi–

Centi- if a metric prefix meaning one-hundredth (of). An example is a centimeter, which is one-hundredth of a meter. The centi- prefix is a New Latin prefix that means ‘hundred.’

This is also true of the cent, a currency used in many countries worldwide but most famously in America. The American Cent is one-hundredth of a dollar.

What is a Metric Prefix?

A metric prefix is a prefix that is used to show multiples of a unit of measurement. Examples of these include:

• Kilo-, which is used to indicate one thousand of something; for example, a kilogram is one thousand grams
• Deca-, which is used to indicate ten of something, for example, a decade which is ten years
• Milli-, which is used to indicate one-thousandth of something; for example, a meter contains one thousand millimeters
• Micro-, which is used to indicate one-millionth of something; for example, a gram contains one million micrograms

What is the difference between Cent and Centi-?

The prefix centi- is also sometimes used about something involving one hundred, such as a centipede whose name translates to ‘hundred foot’ or ‘hundred-footed.’ The number of legs on a centipede varies from less than 40 to over 170.

One example of the ‘cent’ prefix to indicate one hundred of something is a century, a time of one hundred years.

Another well-known use of the ‘cent’ prefix is for Roman Centurions, who were officers in the Roman Army in Ancient Times who commanded a group of one hundred legion

 

A toucan is a type of bird with 40 different species ranging in size – the smallest being seven inches and the largest two feet long. Their scientific name is Ramphastos toco. They live on an omnivore diet which means they eat plants and animal meat. They are also close relatives of the woodpecker; they belong to the same order, Piciformes. Woodpeckers make up 400 species of Piciformes, with toucans being much smaller.

Did you know?

• A toucan can live for up to 20 years.
• The toco toucan is the largest and best – they weigh two pounds and can grow up to 25 inches long.
• Their bill (beak) accounts for half of their length.
• Their colorful bill makes them one of the world’s most popular birds.
• A toucan can use its bill to regulate blood flow, allowing them to distribute heat from the body to keep them cooler.
• Toucans and woodpeckers share several characteristics and are considered to be closely related.
• Toucans aren’t that good at flying and spend most of their time hopping along in the trees.

Well-known species of toucan

• Toco Toucan;
• Keel-billed Toucan;
• Channel-billed Toucan;
• Aracari;
• Green-billed Toucan;
• White-throated Toucan;
• Ramphastos;
• Guinanan Toucanet;
• Yellow-eared Toucanet;
• Spot-billed Toucanet;
• Selenidera;
• Golden-collared Toucanet.

Toucan bill

Male and female toucans have colorful and long bills (beak). The account can also play a part in courtship and in self-defense too. It’s made from keratin – the same protein that makes up and helps with the growth of our hair and nails.

The size of a toucan’s bill is to frighten predators away, but it provides little use when they are fighting. They also use the account to help with eating by using it to help them reach for fruit on branches. In addition to fruit, a toucan also likes to eat insects, eggs, and nestlings of young birds.

Toucan fact file

Scientific name:	Ramphastos toco
Type:	Bird
Diet:	Omnivore
Group name:	Flock
Lifespan:	Up to 20 years
Weight:	20 ounces
Size:	Body = 25 inches bill = 7.5 inches
Class:	Aves (bird)
Family:	Ramphastidae
Order:	Piciformes

What do toucans eat?

In the wild, toucans eat animals and plants, including berries, fruits, lizards, insects, and even small birds. In captivity, they usually eat similar foods to match their needs but wouldn’t need to forage. Foods in captivity can include crickets and other insects, fruit, and vegetables.

Did you know that toucans don’t chew their food and cannot cut it into pieces as parrots do? This is because they also don’t have a crop, a dilated pouch of the esophagus that helps store their food. So when zookeepers feed toucans, they usually give food in small bite-size chunks, making it easy to swallow.

Toucan habitat

Although there are different types of toucans, they all like to live in similar habitats. A toucan’s habitat is located in a rainforest, particularly a tropical one. However, they love warm climates with plenty of rainfall too. Therefore, they choose to live in Central and South America, where their preferred habitat is a nest made in a hollowed-out tree cavity. When nesting, a toucan turns its head back to get comfortable; it settles its bill down behind its back and tucks it under its wing.

A few toucans also chose to live only in mountainous areas. Within the mountains, toucans inhabit a canopy high up in the tallest trees. Here, toucans find all the food they need within the treetops, making it the perfect habitat.

Toucans spend most of their morning visiting fruit trees in their habitat for food. They then make longer journeys away from home to other fruit trees to forage further.

Behavior

Toco toucans tend to hop more than they do fly. They feed individually or sometimes in the canopy (a group of toucans). In the rainforest, they use their bright-colored bill as a good way to camouflage in dappled light. Toco toucans, in particular, like to nest in tree cavities – where they lay their eggs and can lay up to four at once.

To communicate with one another, toucans make a lot of noises – including grunting, snoring, and croaking like frogs. They also are very social and can travel in flocks of up to 22 individuals. It’s also known that toucans are monogamous during the mating season, and while they raise their young, the male and female remain together from gestation to birth.

Did you know that young toucan don’t have a long bill at birth; it grows over time and doesn’t reach full size until several months?

Conservation

Luckily, these birds are listed as ‘least concern as they’re not at risk of becoming endangered as they populate a large range across South America. However, there have been records of them declining as they’re hunted for food and illegal pet trade.

Humans are one of the biggest threats as there’s an increasing trend of toucans being captured to be kept as pets, which is illegal as these birds are not suitable to be domesticated.

Another big factor in their numbers decreasing is habitat loss. As rainforests are being chopped down and turned more residential, e.g., into roads, farms, and buildings, toucans are losing their homes. One toucan that has suffered hugely is the yellow-browed toucanet; it has a small habitat range in Peru. However, Coca growers have taken over their habitat. This makes this toucan one of the first to be listed as endangered.

The Toucan is also sadly hunted in Central parts of America and the Amazon too. Many hunters have been known to try and mimic toucan calls to entice them to the hunter. Most toucans are hunted to be sold in the illegal pet trade business, while others can be trophy hunted; these hunters usually stuff the toucans and keep them on display.

It’s roughly estimated that there are around 10,000 mature toucans around the globe, although it’s believed this is decreasing.

What can you do to help protect toucans and their habitat?

Toucans aren’t considered threatened, but there are some ways you can help to keep protect their conservation. For example, you could help by avoiding products made from rainforest wood to help protect toucan’s habitat.

Life at the zoo for toucans

Many toucans live in zoos worldwide, and their diet and habitat differ when they live in captivity. Toucans in captivity are fed pellets specially made for their bills, fruit, vegetables, and crickets. They are also provided fruits like bananas as a reward when training them.

Reproduction of the Toucan

All species of toucans nest within cavities in the tree trunks. Different species, however, lay differently; for example, some species lay one single egg while others can lay up to five. The eggs called chicks, take around 15 to 20 days to hatch; they then begin to fly when they’re six to eight weeks old.

The chicks hatch with their eyes closed and bare skin and depend on their mother to survive. When the chicks reach three weeks of age, their eyes open, and they begin to form feathers. They remain in the nest with their mother for six to eight weeks and start to grow into their bill. However, while the chicks stay in the nest, the mother must watch on predators such as eagles, hawks, owls, and jaguars as they often invade their nests. To protect themselves, toucans use their loud voice and bill to keep predators away. They usually hit their account against a branch creating a loud noise to try and scare them away.

Did you know that toucans use their bill as part of their courtship ritual?

Toucan Lifespan

It’s believed that toucans can live up to 20 years in the wild; however, in zoos, their life span decreases to around 18 years on average.

Toucan Facts

• Toucans adopted their name because of the noise they make; they can resemble a frog croaking, chirping, barking, and donkey-like noises.
• Female toucans have higher vocal ranges than males.
• A toucan can use their bill as part of its mating ritual, tossing fruit to one another from its bill.
• Toucans can only fly for small distances as their wingspan is small and is around the same length as their bodies.
• They are social birds that like to travel in groups of 22 birds to search for food.
• Toucans have the largest bill of any bird in the world.
• Toucans take shelter in hollowed-out trees created by their cousins – woodpeckers.
• A chick is incubated for 20 days. When they’re born, they don’t have their usual long bill. Instead, they grow into it over time.
• The average lifespan is around 20 years.
• A whole array of colors is possible for a toucan’s bill – not just the conventional orange; they can also be brown, red, or green!
• Humans, snakes, and jaguars are the biggest predators of toucans.
• A constellation was named after the toucan; it’s called the tucana!
• The Toco toucan is the largest and most well-known species.
• One of the oldest toucans is said to have lived for 26 years.
• The smallest toucan species is called the aracari.
• The toucan’s bill releases heat.
• Although a toucan’s bill looks large and big, it’s very light.
• A toucan is believed to be a sign of intelligence.
• Some people keep toucans as pets.
• Toucans mate once a year.
• A toucan’s tongue is said to resemble leather.

Static electricity is an unbalanced charge that is not moving. It’s the build-up of an electrical account on the surface of an object.

It represents the excess charge in a transfer of electrons, often when two objects are rubbed together.

A static shock occurs when this build-up of static electricity discharges.

It is called static electricity because the charge is fixed, which means it doesn’t move and stays in one area without flowing or moving.

Atoms are a key part of this process. Atoms are made up of neutrons, protons, and electrons. The electrons spin around the outside of the atom. When the surfaces of two objects come into contact with each other, the electrons move from one object two another, which creates a static charge. As a result, one thing will have a positive direction, and one will have a negative control.

The object that gains electrons becomes charged negatively, while the thing that loses electrons becomes charged positively. This is because electrons have a negative charge.

Examples of static electricity

There are examples of the presence of static electricity everywhere around us. For example, ever wondered why we use fabric softeners for clothes in the washing machine? That’s because the clothes rub against each other during the cycle and create static electricity.

Another common example is lightning, where positive and negative charges in a cloud create an electric current and discharge electricity to the ground.

You can create static electricity by rubbing two balloons together – this creates a large charge, which is why balloons charged with static electricity can stick to walls and make your hair stand on end!

Just like magnets, items with different charges (such as one with a positive direction and one with a negative charge) will attract each other, and those with similar accounts will push away from each other.

When your hair becomes charged with static electricity, each piece will have the same charge, which means they will all try to push away from each other. This is what gives it that signature straight-up look.

How is static electricity used?

Surprisingly, static electricity is used in many ways in our everyday lives! For example, did you know it’s used in photocopiers and printers? They use static electricity to attract ink to the paper.

Static electricity is also used to remove dust, dirt, and pollution. First, the static charge is applied to the dust, which can be removed by pulling it with a negative control.

Fun facts about static electricity for children

• Static electricity builds up faster than normal on a dry, non-humid day
• It can measure thousands of volts, but it has a small current and only lasts a short amount of time
• The stimulation of nerves causes the feeling of a static electric shock as the neutralizing current flows through your body
• When clouds clash together, they create static electricity, which forms lightning
• Even though static electricity is mostly harmless, it can be difficult to research because a large charge can damage equipment
• Like all types of electricity, static electricity travels at light speed

What is mass?

Mass is the measure of how much matter is in an object. It generally refers to the weight of an object, though mass and weight are not the same. Weight refers to gravity’s force on a person, planet, or entity. Mass instead refers to the amount of matter (protons, neutrons, and electrons) an object is made up of. The weight will be added if you weigh an object on two planets because gravity differs between worlds. The mass would be the same because the amount of matter that something is made of wouldn’t change, or at least not in the same way weight would. Mass can vary due to ‘mass loss,’ caused by the atmospheric escape of gases.

Planetary mass is the term we use when measuring the mass of a planet or planet-like astronomical object. We have a specific way of measuring the mass of planets in our solar system. This is the IAU or the astronomical system of units. First, we calculate the mass of the planets in the solar system relative to the Sun. When comparing the planets in our solar system, it’s typical for the other worlds to be compared to either Earth or Jupiter. This is because earth works well for comparison as a standard terrestrial planet. In contrast, it’s easier to compare gas giants (and also exoplanets and brown dwarfs) to Jupiter instead, as Jupiter is a gas giant planet.

Did you know? Mass is usually measured in kilograms.

The mass of the Earth

The mass of the Earth is approximately 5.9722 x 10²⁴ kg. Earth mass is used as a standard measurement in astronomy and is represented by the symbols in the image below:

The mass of the Earth is mostly made up of iron and oxygen. These represent about 32% of the Earth’s mass each. Magnesium and silicon make up another 15% each, then calcium, aluminum, and nickel account for about 1.5% each.

Measuring the mass of the Earth precisely is very difficult. It is equivalent to measuring the gravitational constant; the fundamental physical constant is known with the least accuracy.

A fundamental physical constant is a quantity believed to be universal and has a constant value in time. For example, two of the most recognizable physical constants are the speed of light (c) and the gravitational constant (G).

The mass of the Earth was first measured with any degree of accuracy in the Schiehallion experiment. This experiment took place in the 1770s and was within about 20% of the modern ‘correct’ value.

The mass of planets in the solar system (10²⁴kg)

• The mass of Earth is 5.9722
• The mass of Mercury is 0.330
• The mass of Venus is 4.87
• The mass of Mars is 0.642
• The mass of Jupiter is 1898
• The mass of Saturn is 568
• The mass of Uranus is 86.8
• The mass of Neptune is 102

A Bunsen burner is a common piece of laboratory equipment that produces a single open flame using gas.

It is used in schools during scientific experiments to heat substances and chemicals.

It is named after German chemist Robert Bunsen.

How do Bunsen burners work?

Bunsen burners are fuelled by gases such as methane and propane.

The gas is provided through rubber tubing attached to togas taps in a classroom.

Temperature

Bunsen burners provide different levels of heat.

The temperature can be manipulated using the hole at the base of the burner.

The burner produces a safety flame if the air hole is fully shut.

This is yellow and is more visible to ensure safety when it is not used.

When the air hole is open, it produces a blue flame.

The air hole can be partially opened to produce a cooler flame and opened fully to create a hotter flame that heats things quickly.

Features of a Bunsen Burner

• The collar is used to obstruct or open their hole and influence the temperature
• The tubing attaches to the gas tap to provide fuel for the burner
• Their hole controls the temperature
• The base is what the tubing, chimney, and components are fixed to
• The chimney is the metal tube that the flame comes out of
• Theflameprovides heat and can be either yellow or blue

Bunsen Burner Safety

When using a Bunsen burner, remember to:

1. Put on protective goggles
2. Tie hair back
3. Ensure ties are tucked in
4. Place the burner on a heat-proof mat
5. Ensure you hold only the collar and tubing when opening or closing the air hole

Subtraction is simply the process of taking one quantity and removing part of it to work out what is left. It is the opposite of addition because we are reducing the value of the number rather than increasing it by adding more numbers.

You can subtract more than one number away from each other, but this usually involves using parenthesis and understanding number facts like number order.

It’s a great idea to introduce subtraction with some examples. There are lots of different ways we can think about teaching subtraction. Talking about a few other methods is a good way to build confidence when children learn about removal.

Showing Subtraction in Maths

Subtraction is usually written with a minus sign between the two subtraction terms. This is because the language of these terms comes from the Latin language. For example, the word removal is an English word, but it comes from the Latin verb subtrahend, where ‘sub’ means ‘from under’ and ‘there’ means to pull. This means the word subtract means to ‘draw from below’ or ‘to take away.’

Terms for Subtraction in Maths

There are lots of terms for subtraction in maths. We must note them to know when subtraction calculations are being discussed or referred to. In addition, they are good cues for children to watch out for in word problems so that they know which operations they need to use.

One of the most common words for subtraction is ‘taking away.’ As you remove the value of one number from another, you take them away from each other. So if we start with six chocolate bars and four remaining, we’ve taken away 2.

Sometimes we focus on subtraction as ‘finding the difference.’ This is because we take one number away from the other and are left with the difference. This focuses more on the answer itself than the equation. The answer is the difference between our original two or more numbers. For example, when we took away two chocolate bars, the difference between 6 and 4 was 2.

Other terms for subtraction in maths are minus, decrease and deduct. These are great terms for children to use when building a number sentence.

More Complicated Terms for Subtraction

Sometimes, however, terms for subtraction in maths mean the numbers you are working with themselves rather than the removal process or the result. These terms for subtraction are called the minuend and subtrahend. The minuend is the first number, the number which you take the other away from. The subtrahend is the subtracted number, the one you take away. Then, of course, we are left with the difference.

Teaching Subtraction as an Inverse of Addition

When children are first introduced to numbers and counting, we always ten to start by counting upwards: 1, 2, 3, 4, 5. Naturally, we usually learn about addition (increasing values) before subtraction.

Having a good grasp of addition can help children when they learn about subtraction, as they can think of inverting operations like this:

2 + 3 = 5

5 – 2 = 3

You can easily demonstrate this principle using objects. Show children how to physically add or remove some from a set, using addition and subtraction vocabulary as you go.

Teaching Subtraction Using a Number Line

Number lines can provide a clear visual representation to help you demonstrate subtraction to children. In addition, number lines are easy to understand and are something children will meet in school from Year 1.

Encourage children to find their starting point on the number line and then count down to find their answer. They can also learn subtraction facts with numbers up to 20, such as 20 – 3 = 17.

This is a great starting point for simple sums before children move on to dealing with larger numbers.

Teaching Subtraction Vocabulary

Talking about subtraction differently is a great way to help children grasp its concept. Here are many examples of how to phrase a subtraction problem for children.

• What is the difference between 7 and 3?
• Take away two from 8.
• What is 9 minus 2?
• Decrease 11 by 5.
• If I take three from 8, how many are left over?
• How much is less four than 10?
• Subtract eight from 12.

Why not ask children to list as many ways to describe subtraction as possible? It is a good idea to test their knowledge with simple questions like this to develop their maths confidence.

A Venn diagram is a visual organizer of overlapping circles that explores the relationship between different things.

They are commonly used to organize objects, numbers, and shapes.

Each circle is given a rule or title related to the information.

Each piece of information is then sorted into the most relevant circle.

Information that meets the rule of both circles is placed in the overlap between them.

Venn Diagram Example

The following Venn diagram explores the relationship between different shapes.

In this example, blue shapes must be put in the first circle, and shapes with curved sides must be placed in the second.

Let’s take a look at our shapes.

These shapes must be sorted into the relevant sections of the Venn diagram.

Shapes that are not blue and do not have curved sides cannot be sorted onto the diagram, so the red square and the green hexagon are excluded.

Now that we have excluded the shapes that do not fit either rule, the rest can be sorted into the Venn diagram.

Shapes that fit both rules must be placed in the middle.

This is a good example of how Venn diagrams can organize shapes, but they can be used to explore the relationships between various things.

They can even be used to find similarities and differences in the animal kingdom.

Who Invented Venn Diagrams?

Venn diagrams are named after their creator, John Venn, an English mathematician specializing in probability and statistics. Venn first revealed his invention in a paper published in 1880.

In the article, Venn calls his diagram “Eulerian Circles” about an earlier visual diagram invented by the Swiss mathematician Leonhard Euler.

John Venn is also known for his pioneering work in computer science.