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.
