Although urine is sterile, it has hundreds of different kinds of wastes from the body. All sorts of things affect what is in your urine, including last night’s dinner, how much water you drink, what you do for exercise, and how well your kidneys work in the first place. This experiment will show you how the kidneys work to keep your body in top shape.
We have done some extensive experiments on taste buds: how they are categorized, what tastes they recognize, and we have even mapped their location on your tongue. But we haven’t yet mentioned this fact: not all people can taste the same flavors!
So today we will check to see if you have a dominant or recessive gene for a distinct genetic characteristic. We’ll do this by testing your reaction to the taste of a chemical called phenylthiocarbamide (or PTC, for short). The interesting thing about PTC is that some people can taste it – and generally have a very adverse reaction. However, some people can’t taste it at all.
Stethoscopes are instruments used to amplify sounds like your heartbeat. Your doctor is trained to use a stethoscope not only to count the beats, but he or she can also hear things like your blood entering and exiting the heart
and its valves opening and closing. Pretty cool!
Today you will make and test a homemade stethoscope. Even though it will be pretty simple, you should still be able to hear your heart beating and your heart pumping. You can also use it to listen to your lungs, just like your doctor does.
Today you will make a calibrated, or marked, container that you will use to measure your lung capacity. You will fill the calibrated container with water, slide a hose into it, take a really deep breath, and blow in the hose. As the air in your lungs enters the container, it will push out the water inside. Just blow as long and as much as you can, then when you flip the bottle over you will be able to read the amount of water you have displaced. If you will subtract the water displaced from the total amount of water in the bottle, the result is your lung capacity.
Food and air both enter your body through your mouth, diverging when they reach the esophagus and trachea. Food goes to the gastrointestinal tract through your esophagus and air travels to your lungs via the trachea, or windpipe.
You will be making a model of how your lungs work in this lab. It will include the trachea, lungs, and the diaphragm, which expands and contracts as it fills and empties your lungs.
Digestion starts in your mouth as soon as you start to chew. Your saliva is full of enzymes. They are a kind of chemical key that unlock chains of protein, fat, and starch molecules. Enzymes break these chains down into smaller molecules like sugars and amino acids.
In this experiment, we will examine how the enzymes in your mouth help to break down the starch in a cracker. You will test the cracker to confirm starch content, then put it in your mouth and chew it for a long time in order to really let the enzymes do their job. Finally you will test the cracker for starch content and see what has happened as a result of your chewing.
When you exercise your body requires more oxygen in order to burn the fuel that has been stored in your muscles. Since oxygen is moved through your body by red blood cells, exercise increases your heart rate so that the blood can be pumped through your body faster. This delivers the needed oxygen to your muscles faster. The harder you exercise, the more oxygen is needed, so your heart and blood pump even faster still.
An oxygen and carbon dioxide exchange takes place in your bloodstream. When you breathe air into your lungs it brings in oxygen, which is carried from your lungs by red blood cells in your bloodstream. Cells of your body use the oxygen and carbon dioxide is produced as waste, which is carried by your blood back to your lungs. You exhale and release the C02. You will study this exchange in today’s lab.
You will be using a pH indicator known as bromothymol blue. When you exhale into a baggie, the carbon dioxide will react with water in the bag. This reaction produces carbonic acid, which starts to acidify the water. More breathes in the bag equal more carbon dioxide, which equal a lower (more acidic) pH. You will notice the bromothymol will turn green when the pH of the water is right about 6.8 and it will turn yellow when the pH drops further to 6.0 and lower.
Your body moves when muscles pull on the bones through ligaments and tendons. Ligaments attach the bones to other bones, and the tendons attach the bones to the muscles.
If you place your relaxed arm on a table, palm-side up, you can get the fingers to move by pushing on the tendons below your wrist. We’re going to make a real working model of your hand, complete with the tendons that move the fingers! Are you ready?
Did you know that the patterns on the tips of your fingers are unique? It’s true! Just like no two snowflakes are alike, no two people have the same set of fingerprints. In this experiment, you will be using a chemical reaction to generate your own set of blood-red prints.
In this lab, we are going to make an eyeball model using a balloon. This experiment should give you a better idea of how your eyes work. The way your brain actually sees things is still a mystery, but using the balloon we can get a good working model of how light gets to your brain.
The tongue has an ingenious design. Receptors responsible for getting information are separate and compartmentalized. So, different areas on the tongue actually have receptors for different types of tastes. This helps us to separate and enjoy the distinct flavors. In this experiment, you will be locating the receptors for sweet, sour, salty, and bitter on the tongue’s surface.
We now know that odor molecules are diffused throughout a room by the motion of air molecules, which are constantly moving and bumping into them. We also know that warm air moves faster than cold air, and that increasing the movement of the air (like with a fan) will increase the diffusion process.
In this experiment, we look at what happens when the odor molecules find their way into your nose. Your nose has smell cells located in a small area called the olfactory epithelium. We will use them here to match smells with other smells.
In addition to looking pretty neat with all those loops and whirls, your fingertips are great at multitasking. The skin on them has a ton of receptors that help us to gather a lot of information about our environment such as texture, movement, pressure, and temperature.
This experiment will test your ability to determine textures by using touch receptors. You will use shoeboxes with holes cut into them to make texture boxes. Each box will have a textured surface that you can feel, but not see. Through the receptors in your fingers, you will determine whether the surface is rough, waxy, soft, or smooth.
Did you know that your tongue can taste about 10,000 unique flavors? Our tongues take an organized approach to flavor classification by dividing tastes into the four basic categories of sweet, sour, salty, and bitter.
For this experiment, you will need a brave partner! They will be blindfolded and will be attempting to guess foods. Relying only on their sense of taste, they will try to determine what kind of foods you are giving them.
This experiment has two parts. For the first half, you will mix two chemicals that will produce heat and gas. The temperature receptors in your skin will be able to detect the heat. Your ears will detect the gas at it vibrates and escapes its container.
In the second portion you will demonstrate a characteristic in a chemical reaction. For this experiment, it will be an endothermic reaction, which is the absorption of heat energy. This type of reaction is easy to notice because it makes things cold to touch. The chemical you will be using, ammonium nitrate, is actually used in emergency cold packs.
Like sound, light travels in waves. These waves of light enter your eyes through the pupil, which is the small black dot right in the center of your colored iris. Your lens bends and focuses the light that enters your eye. In this experiment, we will study this process of bending light and we will look at the difference between concave and convex lenses.
Skin has another function that it vital to your survival: temperature regulation. Being exposed to high temperatures causes your skin’s pores to open up and release sweat onto your body. This helps cool us off by the resulting process of evaporation.
Your pores will close in extremely cold temperatures. Also, the body stops blood flowing to the skin in order to conserve heat for the important vital organs and their processes.
In this lab, we study the moisture that your skin produces – even when you are not aware of it!
Your fingers have receptors which perform various jobs. In addition to touch, they can detect pressure, texture, and other physical stimuli. One specialized type of receptors is called Ruffini’s receptors. They are good at identifying changes in pressure and temperature. In this experiment, we will test their ability to distinguish between hot and cold temperatures. We are actually going to try and trick your Ruffini endings. Do you think it will work?
Your optic nerve can be thought of as a data cord that is plugged in to each eye and connects them to your brain. The area where the nerve connects to the back of your eye creates a blind spot. There are no receptors in this area at all and if something is in that area, you won’t be able to see it. This experiment locates your blind spot.
Peristalsis is the wavelike movement of muscles that move food through your gastrointestinal tract. The process of digestion begins with chewing and mixing the food with saliva. From there, the epiglottis opens up to deposit a hunk of chewed food (called bolus) into your esophagus – this is the tube that runs from your mouth to your stomach. Since the esophagus is so skinny, the muscles along it must expand and contract in order to move food down. In this activity we will examine that process.
Everything living produces some sort of odor. Flowers use them to entice bees to pollinate them. We know that the tastes of foods are enhanced by the way that they smell. As humans, each of us even has own unique odor.
In this lab, we look at the diffusion of scents. They start in one place, but often end up spread around the room and can be detected by many people.
The eye is a complex structure that detects and focuses light. Light first enters the eye through the cornea, a clear protective layer on the outside of the eye. The pupil, a black opening in the eye, lets light in. In dark rooms, the pupil will become larger, or dilate, in order to let in more light. If the room suddenly becomes bright, the pupil will become smaller. The pupil is surrounded by the brown, blue, grey, or green iris.
After passing through the pupil, light goes to the lens which, like a hand lens, is a clear curved structure that helps focus light on the retina, in the back of the eye. The retina is where the rods and cones are found.
This video is an old instructional film shown to pre-med students in the early 50s you might enjoy watching:
Does it sound impossible to read 25,000 words per minute with a 75% comprehension? Not at all! I learned how to photoread using this cool technique developed by Paul Scheele that I am going to share with you. You’ll be able to digest entire textbooks, articles and newspapers that have been piling up, or read hundreds of emails just a matter of minutes. And no, it’s not ‘speed reading’, and it’s not ‘photographic memory’ either. It’s not magic – but it really works! Anyone who can read a book can learn how to do it.
Most folks read the same way they were taught in grade school – at about 200 words per minute with a 55% comprehension level. And sadly, most remain at this level while stacks of untouched newspapers, magazines, mail, articles, books and reports clutter your living space. When will you ever find the time to read for pleasure with so much to sift through? So many people are trying to cope in the information age using the same reading skills they learned in grade school!
The challenge isn’t whether photoreading is possible, but rather how to incorporate photoreading into your everyday activities, just like eating and sleeping. After I learned how to photoread, I felt much more on top of things in my life, because I had the information I needed to make effective decisions. While I used to spend days reading science textbooks and technical journals, now I only spend minutes per document and I have a clear desk feeling at the end of the day, both at my office and in my home. I can keep up with all the latest daily news in 10 minutes.
The main presumption when picking up a book is that you must read every word in order to understand its message. Not only that, but the book must be read all at one speed: painfully slow.
You know from experience that you don’t have to read every word to get the gist of what a paragraph is talking about. Nor do you have to read an entire textbook at the same speed. We’re going to learn how to super-read, rapid-read, and photoread. Think of it as giving your car a new set of gears: you only had first gear available in your car, and now I’m going to show you how to use 2nd gear, 3rd gear, and overdrive.
Your eyes have two different light receptors located on the back of the eyeball. These are the rods, which see black, white and grays, and the cones, which see color. In order to adapt to the dark, our eyes make a chemical called visual purple. This helps the rods to see and transmit what you see in situations where there is little light.
Your pupils also increase in diameter in the darkness. This allows for a slight increase in the amount of light entering your eye. This combination of visual purple and more light makes it possible for you to see in darker situations.
Levers are classified into three types: first class, second class, or third class. Their class is identified by the location of the load, the force moving the load, and the fulcrum. In this activity, you will learn about the types of levers and then use your body to make each type.
You know that sound comes from vibration which are picked up by the pinna (external part of the ears). Then the vibrations vibrate your tympanic membrane, which in turn vibrates the ossicles and then the cochlea. The cochlea sends information through the auditory nerve and sends it to the brain, which recognizes it as sound.
In this lab, you will testing your ability to sort and match different sounds.
Have you ever held a plastic ruler over the edge of a desk or table and whacked the end of it? If so, you would notice a funny sound. This sound changes if you change the length of the ruler that is hanging over the edge. The sound you hear is made by the ruler’s vibrations.
In this lab, we begin to learn about sound. You know it is collected and deciphered by your ears, but did you also know that all sound is made when something vibrates? It could be a guitar string, vocal chords in your throat, or a plastic ruler that is hanging over the edge of the desk: vibrations make sound.
How do you think animals know we’re around long before they see us? Sure, most have a powerful sense of smell, but they can also hear us first. In this activity, we are going to simulate enhanced tympanic membranes (or ear drums) by attaching styrofoam cups to your ears. This will increase the number of sound waves your ears are able to capture.
It may seem like walking across a balance beam and listening to your favorite song are very different activities, but they both depend on your ears. Ears are the sense organs that control hearing, which is the ability to detect sound. Ears also sense the position of the body and help maintain balance when you walk a balance beam or ride a bike.
Imagine a pebble being dropped into a lake. Waves of water go off in all directions. A similar thing happens when a car driving down the street honks its own. Waves go off from the car in all direction. The difference is that these are not waves of water, but instead are sound waves, which travel through the air. If you are nearby, some of those sound waves make it to your ear.
Here’s a video that shows you how everything works together so you can hear:
The pinna, or outer ear, which is the part of your ear that you can see, gathers up some of the sound waves, sends them down the ear canal, and eventually they strike the eardrum. The eardrum is a thin membrane that vibrates like a drum when the waves hit it. The vibrations pass three tiny bones, called the hammer, anvil, and stirrup, as well as a membrane called the oval window, causing them all to vibrate.
From the oval window, the vibrations go to the cochlea, liquid-filled space lined with hairs. The vibrations make waves in the cochlea’s liquid, just like waves in a pond, causing the hairs to move. The movement of the hairs sends a nerve impulse through the auditory nerve to the brain. The brain interprets the message and “tells” you what you have heard.
This video is an old instructional film shown to pre-med students in the early 50s you might enjoy watching:
Along with hearing, the ears play a major role in balance. Inside the ears are semicircular canals which are lined with hairs and full of liquid. When the body moves in one direction, the liquid in the semicircular canals move, causing the hairs to move. This sends a message to your brain, which gives instructions for the body’s muscles to contract or relax. This keeps you balanced.
There’s a cool video of a camera going inside the ear… watch out for the wax!
Some groups of muscles are stronger than others because each group is designed for a different and specific function. It just makes sense that the muscle groups in our legs would need to be stronger than the ones in our toes.
For this experiment, you will use a bathroom scale to test the strength of various muscle groups.
The skeleton is your body’s internal supporting structure. It holds everything together. In addition to providing support, bones act as shock absorbers when you jump, fall, and run. Bones have big responsibilities and so they must be really strong. They also need to be arranged properly for the best support and shock absorption.
In this experiment, we will look at the internal arrangement of the bones holding together your body.
Your body is made of organs, like your heart, lungs or stomach. These organs work together to allow you to breathe, eat, move, and do just about everything else you need to do. Organs working together are called organ systems. Although all organ systems are important, and necessary for us to survive, the most important system might be the nervous system, the system that controls all the others. This system not only controls all the systems of your body but also allows you to learn and use language, senses conditions inside and outside your body and prepares you to fight or flee if you are in a dangerous situation.
This is a video about the more advanced concepts about neurons, nerves, and signals:
Imagine you walk into your home one night and it’s pitch black. You quickly flick on a light switch and the room is immediately lit up. You may have never thought about it, but it’s kind of amazing that this happens. Even though it may be a long distance from the light switch to the actual light, the light comes on.
Fortunately, messages in your nervous system also travel at the speed of electricity. The nervous system is made of bundles of nerve cells called nerves. Nerve cells called neurons send messages, called nerve impulses, throughout the body. Since these messages are electrical impulses, they travel very quickly. Neurons are also covered with a fatty covering called myelin which insulates the neuron, like the plastic on the outside of a wire, allowing the nerve impulse to travel even faster.
Look at the shape of the neuron. These cells are the perfect shape for their job of sending messages all over the body. The small extensions on the end of the cell are called dendrites and get nerve impulses from other cells. The longer extension at the other end of the cell is called an axon and sends nerve impulses to other cells. The central part of the cell, between the dendrites and axon, is called the cell body. This part of the cell contains the nucleus and all the organelles, which are small structures inside the cell. The place where the axon of a nerve cell meets the dendrites of another nerve cell or another type of cell is called a synapse.
Neurons can be classified, or put into groups, based on their job in the body. Sensory neurons carry messages from the organs to the brain and spinal cord. Motor neurons carry messages from the brain and spinal cord to organs, glands, and muscles.
Have you ever wondered how cells communicate? Here’s a video for advanced, curious students:
As you can see, the nervous system does many things and has many parts. Consider the chart below, which lists the divisions of the system. Each part of the system plays a unique and important role in allowing the other body systems to function.
Our sense of touch provides us with information that helps us to process and explore our world. Nerves play an important part in the sense of touch by being the wires that carry signals from the skin to the brain. But the body has a plan in place so that our brains don’t get overwhelmed with too much information. This plan is a lot like a blueprint for wiring a house. Just like a house has light switches and electrical outlets in strategic locations, our bodies have touch receptors of various numbers based on their location. In this lab, we will explore an arm to determine where the highest concentrations of nerves are in that limb.
Bones are made up of several parts; bone marrow (red and yellow), spongy bone, compact bone, and the periosteum. Bone marrow makes blood cells. Red blood cells are made in the red marrow, while white blood cells are made in the yellow marrow. When babies are born they only have red marrow. Spongy bone is a light, spongy type of bone found inside bones. Compact bone, on the other hand, is hard and makes up the outer layer of bones. The compact bone layer is covered by a thin white membrane called the periosteum.
Bones begin growing very early, and stop growing between the ages of 18-25. At about eight weeks of development, we form a skeleton of cartilage and other connective tissues. As we grow up, the cartilage becomes bone. Normally, we have all of our bones by our early twenties. We still keep some of the cartilage in areas like our nose and ears.
Joints are essential in how we move. Bones work as levers and the joints work as the fulcrums—making our movement easier. Some joints are fixed; for example, many in the skull. Some allow only little movement; for example, the vertebrae which make up the backbone. Lastly, there are movable joints; for example, our knees and elbows. These make up the three classes of joints: fixed joints, partly movable joints, and movable joints.
The keys to keeping the skeletal system healthy are: eating well, getting exercise, and taking care of injuries to the skeletal system.
Eating a good balanced diet is very important for overall health, but making sure to get specific nutrients help ensure a healthy skeletal system throughout your life! Those nutrients are: calcium and vitamin D. 1300mg of Calcium is recommended (one cup of milk has about 300mg of Calcium) and 200IU of vitamin D (31/2 ounces of cooked salmon is about 360IU of vitamin D). Calcium can be found in dairy products as well as broccoli and cabbage. Your skin makes vitamin D when exposed to sunlight. Additionally, fish is rich in vitamin D.
It’s important to get out an exercise to maintain a healthy skeletal system. When we exercise we put stress on our bones and stimulate them to stay strong. Exercising also keeps the muscles which work with the bones strong. Just remember to stretch and wear all the appropriate safety gear.
Lastly, if an injury occurs—a bone breaks or a ligament tears, for example—it’s important to see a medical professional as soon as possible. Otherwise, the skeletal system may not heal properly!
Involuntary responses are ones that you can’t control, but they are usually in place to help with survival. One good example is when you touch something hot. Your hand does not take the time to send a message to your brain and then have the brain tell your hand to pull away. By then, your hand might be seriously hurt! Instead, your body immediately removes your hand in order to protect it from further harm.
Today you will test an involuntary reflex by using the tendon reflex test. A thick, rubbery band called the patellar tendon holds your knee cap in place. Having one leg on top of the other not only stretches the tendon, but it also makes it possible to see a reaction. You can test the reflex by giving your tendon a tap and watching what happens.
Our cells are happiest when they are in their normal or “home” state. This is a state in which the temperature, the concentrations of molecules, and molecules being produced are all at the levels at which they normally function. This “normal” or “home” state is called homeostasis.
Our cells—and the tissues and organs they constitute—work hard to maintain homeostasis. We can see this in action. When it is cold out and we shiver, that’s our body trying to get the temperature up to normal levels. When it’s hot out and we sweat, that’s our body trying to get the temperature down to normal levels. We see our body trying to maintain homeostasis when we feel hungry, or thirsty. Homeostasis is an important characteristic of living things. If you were in the desert, your body would be working hard to maintain homeostasis—despite the high temperature and the lack of water.
There are many different types of cells in the body, but all of them work to maintain homeostasis. For example, there are specific muscle cells for muscles, specific heart cells for the heart, specific pancreas cells for the pancreas, and skin cell cells making up the skin. The different cell types differ in how they function. They all work together to make sure the body functions normally.
A tissue is composed of specific cells performing the same function. An organ is made up of two or more types of tissues working together. Organs which work together form organ systems. Organ systems work together to maintain homeostasis.
So, how many types of tissues are there? There are four main types of tissue. Tissues are groups of cells which together form specific functions. These types are: epithelial tissue, nervous tissue, muscle tissue, and connective tissue. Epithelial tissue is found in tightly packed surface layers; such as the skin, as well as the lining of the digestive system and the lining of the mouth and nose. Nervous tissue is responsible for relaying information. All together the nervous tissues form the nervous system. The nervous system includes the sensory nerves in the body, nerves in the spinal cord, and the brain.
There are three types of muscle tissue; smooth muscle, skeletal muscle, and cardiac muscle. All three cell types have filaments which change the size. Bone, cartilage, and tendon tissues are examples of connective tissue. Connective tissue connects one part of the body to another and is involved in structural support.
The low blood temperature sends a message to the brain which then sends a message to the adrenal gland, which increases the blood temperature by raising the metabolism. The raised blood temperature then signals to the brain that it’s time to stop sending the message to the adrenal gland. A key way organ systems maintain homeostasis is via a negative feedback loop.
A negative feedback loop simply means that the result is a signal to stop. For example, if you haven’t eaten for a while your body will sense that your blood sugar is low. The low blood sugar acts as a signal for the body to start releasing sugar into your blood. However, once the blood sugar levels are back to normal—homeostasis has been reestablished—that normalcy acts as a signal for the body to stop releasing sugar into your blood.
Many problems can occur if these negative feedback loops do not function properly. For example, diabetes is a disease which results from the blood sugar negative feedback loop functioning abnormally.
The buildup of things like food and bacteria where your gums and teeth meet, and also between your teeth, is called plaque. Where plaque lives is also where the bacteria turns the sugar in your mouth into harmful acids that attack your teeth’s enamel and can lead to gum disease. Regular brushing is a great way to remove plaque and keep your mouth healthy.
This experiment not only explains how your body uses oxygen, but it is also an experiment in air pressure circles – bonus! You will be putting a dime in a tart pan that has a bit of water in it. Then you will put a lit candle next to the dime and put a glass over the candle with the glass’s edge on the dime. Once all of the air inside the glass is used up by the candle, the dime will be easy to pick up without even getting your fingers wet! Ready to give it a try?
Take a deep breath in, and slowly let it out. As you do, think about the breaths you take without thinking about it. The truth is, you probably only think about breathing when you are coughing and having a hard time breathing. Even though breathing is not something we think about regularly, it is absolutely required for the survival of the cells in your body. As you breathe, oxygen flows into the body and carbon dioxide flows out. This very important exchange of gases is the main function of your body’s respiratory system.
Sometimes, people will say “breathing” and “respiration” as though they were the same thing, but they are actually very different. Breathing is the process where air enters the body, goes into the lungs, and exchanges its oxygen for carbon dioxide. This is part of respiration, and is known as external respiration, but it only half of full respiration. Respiration also includes internal respiration, where the blood, full of oxygen, goes to the parts of the body that need it. This process can be learned about in a discussion of the circulatory system, another body system.
The heart is the most important organ in the cardiovascular system. You may heard your heart beat when you were at the doctor’s office, but you may never have thought about what the heart was actually made of. The heart is made of four sections, or chambers. The two chambers at the top of the heart are called the left atrium and right atrium. The two chambers at the bottom of the heart are called the left ventricle and right ventricle.
The job of the atria (that’s the plural of atrium) is to get blood from the other parts of the body. The job of the ventricles is to pump the blood from the heart to other parts of the body. We’ll worry about exactly where the atria are getting the blood from and where the ventricles are sending it to a little later. For now, just make sure you understand that atria get blood in and ventricles pump blood out.
Along with the heart, another important part of the cardiovascular system are blood vessels. There are three main types of blood vessels; arteries, veins, and capillaries. Arteries are blood vessels that carry blood away from the heart. Arteries have thick walls. They need these thick walls because there is a lot of pressure on the blood in arteries. Every time the heart contracts, it creates a force on the walls of the arteries. This force creates pressure. You’ve probably heard of blood pressure, and had your blood pressure taken during a check-up.
Blood pressure is a measure of the pressure on the walls of the arteries caused by your beating heart.
The next types of blood vessels are veins. In many ways, veins are the opposite of arteries. While arteries move blood away from the heart, veins bring blood back to the heart. While arteries have thick walls to handle blood under high pressure, the walls of veins are much thinner, because the blood they carry is under a much smaller amount of pressure. Veins contain valves, which stop the blood they are carrying from moving backwards.
The last types of blood vessels are capillaries. Capillaries connect veins and arteries, and they are tiny. Their walls are only one cell thick, and they are so narrow, blood cells have to go through them single file. In spite of their small size, however, capillaries are the place where one of the most important things in our body happens. Networks of capillaries, called capillary beds, are the places where blood gives off oxygen to the parts of the body, and collects waste products like carbon dioxide. One of the major purposes of the cardiovascular system, oxygen transfer, is happening in these tiny vessels. The more active an organ is, the more capillaries it will need to get oxygen and other nutrients from the blood.
Your blood travels through your body very quickly. You probably already know that you can place your finger on certain points – like the radial artery in your wrist – and count the beats of your heart as it pumps blood throughout your body.
In this experiment, we will explore other ways to amplify your blood’s movement so that you can actually see a visual representation of it.
Digestion involves the breakdown of what we consume into nutrients. The first step is mechanical digestion—chewing. After we mechanically break down the food with our teeth, we begin chemical digestion.
Teeth are small structures found in the mouths of vertebrates. They are calcified, meaning that they contain the element calcium, and are very distinctive based on the type of animal they are found in. Carnivores, or animals that eat meat, have sharp, pointy teeth for ripping and tearing prey. Plant-eating animals, known as herbivores, have larger flat teeth which they use to grind up the tough plant material they eat. Other animals, referred to as omnivores or generalists, eat both plant and animal material. As you might expect, these animals have both types of teeth. Humans fall into this category.
Humans and all other mammals are diphyodont, meaning we will have two sets of teeth in our lifetimes. Not all animals are this way. In fact, rodents and sharks both will continue to grow set after set of new teeth as they gnaw or bite their food. Other animals only have one set of teeth throughout their entire life.
In humans, the front teeth are called incisors. Next to the incisors are the sharp canines. To see how these two types of teeth are used, try a mini-experiment. Take a bite out of a banana and then take a bite of a carrot. Chew them as you would normally, and pay careful attention to what tooth is being used to chew. You’ll notice that for the softer banana, the incisors take the first bites. With the harder carrot, the canines do this job. In both cases, the chewing is done by the pre-molars, which are the teeth next to the canines, and the molars, the large, flat teeth closest to the back of your mouth.
Taking care of your teeth is very important. Brushing your teeth after every meal and flossing every day can go a long way in making sure your teeth stay healthy. If you don’t brush and floss, bacteria can build up over time, leading tartar and plaque on your teeth. If this continues, a small hole, or cavity, can form. Dentists can fill cavities, but this is generally something to be avoided if possible. Your gums can also become infected with bacteria if they are not cleaned. Bleeding gums can be one sign of gum disease. Serious dental procedures, such as extraction (the removal of a tooth) or a root canal are sometimes needed when dental care has been ignored for too long. The best thing to do is to avoid the problem to begin with by brushing, flossing, and visiting a dentist regularly.
Eating and drinking are essential parts of our life. Part of maintaining a healthy lifestyle is making sure to eat and drink the right quantities of the six essential nutrients. Those nutrients are: protein, carbohydrates, lipids, vitamins, minerals, and water.
Does it mean to eat all vegetables? Does it mean to eat only meat? No. A healthy diet is a balanced diet. This is what MyPlate demonstrates. A balanced diet means getting the right amounts of nutrients. MyPlate guidelines are recommendations from the United States Department of Agriculture (USDA). Since 1958 the USDA has recommended a balanced diet in the form of the food pyramid. However, the pyramid proved to be too complicated for most Americans to efficiently use to create diets. In response, the USDA simplified its recommendations in 2011 into the MyPlate format.
We already know what a diet is—the sum of food and drink consumed. Now, what does it mean to have a healthy diet?
The specific advice of the USDA is:
If you’re like me, you like to know about the cool instruments doctors use when they poke and prod you in the standard office visit. I was always curious about what optometrists use during their eye exams. I found an instructional video that teaches optometrists about their tool for examining the fundus here:
Today, some people with vision problems choose to have surgery called LASIK. In this surgery, a laser changes the shape of the cornea correcting the vision problem. As a result, the person usually no longer needs to wear glasses or contacts. However, some problems are not correctable, even with LASIK.
Here’s a video on what it’s like to be blind:
If the vision problems can’t be corrected (as with blind, or no vision), how do people read? The Braille system was developed many years ago. Here’s a video that shows you how it works:
Do you or someone you know where glasses or contact lenses. Glasses and contacts are used to correct vision problems. The two most common eye problems are myopia and hyperopia, and each is fixed a different way.
Myopia is sometimes called nearsightedness. About one third of people have this problem. Myopia happens when the eye is too long. With eye too long, images seen are focused a little bit in front of the retina, instead of on the retina as they would be in a normal eye. People with myopia can see nearby objects clearly. Objects that are far away, however, look blurry. This can be corrected with a concave lens on glasses or contacts. “Concave” means that the lens curves inward, like the inside of a bowl. The concave lens helps focus light on the retina instead of in front of it, correcting the problem.
Hyperopia, which is also called farsightedness, affects about one fourth of people, is pretty much the opposite of myopia. In this disorder, the eye is too short, so images become focused behind the retina. As a result, people with hyperopia can see things clearly when they are far away, but not when they are close up. To correct hyperopia, a convex lens, which is a lens that curves out, like the outside of a bowl, is used in glasses or contacts.
Here’s a video that shows some of the latest technology in eye exams and what optometrists diseases can detect early on:
Some people suffer from both myopia and hyperopia. How can this be? It doesn’t seem possible that the eye could be too long and too short. The answer lies in the lens of your eye. You can think of the lens like a trampoline. As you jump up and down on the trampoline, it moves closer or further from the ground. The lens does a similar thing when you look at things closer together or further away. This makes the overall shape of the eye change slightly. As your trampoline gets older, the springs may begin to wear down, and it may become harder for the trampoline to move. The same thing happens with the lens in your eyes. As a result, many older people develop hyperopia. If these people already had myopia, they will need a lens that has both a concave and convex part. Bifocals are glasses that have these two parts.
If you’ve ever had a blood test, you may have wondered, perhaps as that needle was getting closer and closer, what exactly is the point of this? As it turns out, quite a lot. The standard blood test measures many things. There are also specific blood tests a doctor might order based on a person’s health history or a particular medication he or she is taking. A common blood test is the CBC, which stands for complete blood count. In this test, doctors can obtain counts of red blood cells (RBC) and white blood cells (WBC).
Healthy blood has 4.2 – 6.9 million RBC’s per cubic millimeter of blood and 43,000 108,000 WBC’s per cubic millimeter. That’s a lot of cells!
If a person has anemia, part of the CBC called the mean corpuscle volume (MCV) can help determine the cause. A CBC can also determine the amount of platelets in the blood, a very important number since platelets are needed for blood clotting. A range of 150,000 – 350,000 platelets per milliliter of blood is considered normal. Blood tests also commonly test for cholesterol levels. Cholesterol can clog the blood vessels, making it harder for blood to get around the body. This can lead to heart disease and heart attack. Healthy people generally have less than 225 milligrams of cholesterol per deciliter of blood, although the acceptable amount can increase as people age.
It is important to realize that there are some healthy people who will have blood tests results outside the “normal” range, and some people who are not healthy at all in spite of being within normal limits. This is why blood tests should be interpreted by a doctor or other medical professional. The thing to remember, however, is that blood tests are checking for important medical conditions. So even if it hurts a little for a moment, the test can do an awful lot of good.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!
Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.
Answers:
Please login or register to read the rest of this content.
When you hear the word “bacteria” what do you think of? If you’re like most people, you probably think of things that can make you sick. Although some bacteria do make us sick, this is not true for all of them. In fact, as we’ll see a little later, some bacteria are very helpful.
Did you know that bacteria can have a virus? It’s true! But first, you might be wondering: what’s the difference between viruses and bacteria?
Bacteria grows and reproduces on its own, while viruses cannot exist or reproduce without being in a living cell of a plant, animal, or even bacteria. Size-wise, bacteria are enormous.
The muscles in your body allow you to move. In this lab we will do two quick experiments to explore how your muscles work.