Extend your thinking

Is it possible for food we eat to go into stomach and intestine even when we are upside down?

Yes because Food and water entering the esophagus does not drop down and  fall into the stomach; instead it is pushed through by waves of  contractions (squeezes) from the bands of muscles that encircle the  esophagus

How do we vomit?

Sometimes peristalsis works in reverse and pushes the food in stomach up and out through the mouth. This reverse process of peristalsis is called vomiting. It mostly happens when the food is unsuitable in some way.

If we bite a bread and chew it in our mouth for some time, it will taste sweet. Why?

Bread is a type of starch that is made up of glucose molecules and glucose is, again, a form of sugar.
If you chew on a piece of bread for a while, it will begin to taste sweet because the enzymes in saliva break down the starch into glucose.

Why are we advised to breathe deeply after running a race?

runners breathe heavily after a race because your muscles use ATP's for energy, and ATP's need oxygen to work, so you breathe heavily to replenish (fill)  your oxygen levels.

Why does our voice become rough when we get infection in throat or catch cold?

When you talk, the air that passes through your vocal cords sets off vibrations that make the sound of your voice. So when your vocal cords are  swollen, you may end up with a voice that is rough.

What do you think will happen if blood entering the heart mixed with blood leaving the heart?

the blood entering the heart is polluted when it enters the heart, the heart cleans it up; so when the blood leaves the heart it is clean so if it gets polluted the person may get sick and this leads to his/her death

How is the structure of capillaries related to their function?

Capillaries are sites for gas exchange. Their walls are very thin (one cell layer), making it easy for oxygen and carbon dioxide to diffuse through them.

Explain how our circulatory system completes the work of our digestive and respiratory systems.

Respiratory and the Circulatory system

heart send blood to the lungs, which is then oxygenated, so the blood can then be sent to the rest of the body .

Digestive and the Circulatory system

without the heart-beat from the circulatory system, there wouldn't be any peristalsis which in turn won't push the food down into the digestive system

What would happen to a plant if its leaves were covered with waterproof petroleum jelly?

if its leaves were covered with waterproof petroleum jelly CO2 could not enter the stomata’s of the leaves and O2 could not leave. This would result in the plant's death because it could not carry out photosynthesis.

 What helps the pollen grains to stay on the tip of the style after they land there?

stigma secrete a sugar like substance which will the pollen stick at their places.

Grasses do not have bright-colored flowers. How might this be related to the way these plants are pollinated?

Most grasses are pollinated by the wind. They do not require insects for pollination, therefore they do not need to smell or look pretty to attract insects.

The papaya plant has male and female parts on separate plants. Why is a lonely papaya tree hard to see with fruit?

It is just luck if there is a plant of the opposite sex near enough for insect pollination. So if the other sex papaya plant is not near then its hard for lonely papaya to get pollen's and thus no fruits.

Which fruits are eaten as vegetables?

Tomato is a fruit but it is eaten as vegetable. Olives, plums, tomatoes,  and cucumbers are fruit.

Explain, why a limited plant and animal life is found in deserts?

Because of the dry conditions, there is limited plant and animal life in deserts.

How is the Sun important to the food supply of an ecosystem?

Sunlight is needed in ecosystems because it is the source of energy of all food chains in the ecosystem. If there is no sunlight, plants which are the producers in the ecosystem can´t undergo photosynthesis, die, and the whole ecosystem collapses.

Two kinds of birds live in the same tree. Kind A eats ants that live In the tree. Kind B eats ants and caterpillars. Which species is more likely to survive if the ant population decreases? Why?

Kind B has better chances at survival. Because they are not dependent on ants only.

All the plants and animals of an aquatic habitat will find difficulties in living in other habitats. Why?

Different plants and animals require different living conditions to thrive, eg. goldfish need freshwater while whales, sea water.

Animals and plants are adapted to the conditions of the habitats in which they live. Most animals are only adapted to live in one or two habitats. A walrus could not live in a desert. A rattlesnake could not live for very long in the arctic.

Even though secondary  consumers do not eat plants, how are plants important to their food supply?

Plants are the producers of the ecosystem. They made their own food, Animals that eat only plants are called the primary consumers. Animals that eats other animals are called secondary consumers. so if there will not be plants, there will not be any primary consumers thus there will not be any secondary consumers.

What will happen to all animals of a food web, if green plants are removed?

Everything else dies because plants are producers and the source of food for all organisms.

How does water help us to live?

Water is part of the main things in life, it helps us keep us from not dying from over heating ,it helps us with every single thing, it helps us have gravity, and the moister in the air.

You are hiking and you are thirsty. Would you drink water from a stream? Why or why not?

No, because what appears to be a clear steam can be actually polluted. So if one has to drink from steam they shall clean water by boiling filtering or chemically.

Why do cities and towns purify water before it is supplied to homes?

Cities and towns purify water before it is supplied to homes because of contaminated water and it may cause many diseases.

How protons, electrons and neutrons are alike and different?

Similarity: electron ,protons and neutrons are part of atom.

Difference: electron is negatively charged. Proton has positive charge while neutron has no charge. Moreover electrons revolve around the nucleus while protons and neutrons lies in the nucleus.

Tungsten is an element with 74 protons and 109 neutrons. What is tungsten’s atomic number? How many electrons does tungsten have?

Atomic Number = 74

Number of Electrons = 74

When a glass rod is rubbed with silk, the rod becomes positively charged. What type of particle in the atoms in the rod has been removed?

the electrons have been removed. Since the electrons are negatively charged, the removal of them will cause a net increase of the total charge in the positive.

Explain the presence of puddle of water on the sidewalk one day and its absence on the next day?

The change in temperature will cause water to change its state. If it’s cold water will turn into snow, if it’s hot water will turn into vapors.

When we chew food what kind of changes are we causing to the food, a physical change or a chemical change?

Chemical change. The act of chewing is a physical change but the saliva in mouth has enzymes that help digest food which is a chemical change . Stomach also  has acid that is very strong and also breaks down foods via chemical reactions.

Why do you think chopping of a wood is a physical change but burning of food is a chemical change?

Chopping wood is a physical change. When you chop wood into smaller pieces, it is still wood, it's just in smaller pieces.
Burning wood however is a chemical change because once the wood is burned it is no longer wood it is ash and CO2.

When sugar is heated for a long time, it forms a solid black substances. Identify it as a reversible or irreversible change.

It is an irreversible change because a new black substance is formed and we cannot get the sugar again from it.

Why does conduction not occur at all in vacuum?

Because conduction needs material medium to transfer heat.

Many fast food restaurants pack their hot sandwiches/ pizzas in Styrofoam boxes instead of wrapping them in ordinary paper. Why is the Styrofoam used?

Because Styrofoam is a bad conductor of heat and keep things hot/cold for a long time.

Why is radiation the only type of heat transfer by which the Sun’s energy can move to the Earth?

Because the space between the Sun and Earth is a vacuum, there is no medium for transfer of heat by conduction or convection.

How conduction, convection and radiation are alike and how they are different?

Similarity : Conduction, Convection and Radiation are all modes of transfer of heat.

Difference : Conduction and Convection needs medium to travel but in conduction molecules don’t move from their position and in convection molecules actually move to the source of energy to absorb heat and then move away. Unlike these two radiation doesn’t need any material to transfer heat.

A light wave is bent more as it travels from air to glass than in travelling from air to water. Is the speed of light greater in water or glass?

The speed will be greater in water. Light refracts whenever it travels at an angle into a substance with a different refractive index.

This change of direction is caused by a change in speed. For example, when light travels from water into glass, it slows down, causing it to continue to travel at a different angle or direction. Also refractive index of water is 1.3 and that of glass is 1.5, so light will travel faster in water.

Bending of light in different medium depends on what factors?

The amount of bending depends on two things:

1)    Change in speed which depends on refractive index.

2)    Angle of the incident ray

How rainbow forms?

Rainbows happen when sunlight and rain combine in a very specific way. The beams of sunlight separate into the colors we see in the rainbow as they enter a raindrop. Sunlight is actually made up of different colors that we don’t usually see. When a beam of sunlight comes down to Earth, the light is white. But, if the light beam happens to hit raindrops on the way down at a certain angle, the different colors that make up the beam separate so that we can see them — in the form of a rainbow.

Why don’t we see a rainstorm during most rainstorms?

You put the sun directly behind you.

What colors are reflected by an object that appears black?

Red + Blue = Magenta

Green + Blue = Cyan

Green + Red = Yellow

Red + Green + Blue = White

Suppose a wave move from one side of a lake to the other. Does the water move across the lake? Explain.

Waves travel through water, but they do not carry the water with them.

When sound waves travel from air to water what will happen to the speed at which they are moving?

The speed will increase as sound travels faster in water than air.

When a little boy blows a dog whistle, his dog comes, even though the boy can’t hear the whistle. Explain why the boy can’t hear the whistle but his dog can?

A dog whistle is a type of whistle that emits sound in the ultrasonic range 23000-45000Hz, which people cannot hear but some other animals can, including dogs and domestic cats, and is used in their training.

Sound waves need a material medium to travel. In a science fiction movie, a nearby spaceship explodes. You hear the explosion. Is this realistic?

No because sound needs medium to travel and the space is vacuum.