2020 NOVDEC SCIENCE PRACTICALS

 2020 NOVDEC SCIENCE PRACTICALS WITH ANSWERS

ELECTRON KING SIDE

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ANSWERS

*Q5a*

*DESCRIBE SEXUAL REPRODUCTION IN FLOWERING PLANTS*

Sexual reproduction in flowering plants involves the production of male and female gametes, the transfer of the male gametes to the female ovules in a process called pollination. After pollination occurs, fertilization happens and the ovules grow into seeds within a fruit.

          *Q5b*

 *WHY HEAT IS A FORM OF ENERGY*

Heat is energy transferred between substances or systems due to a temperature difference between them, according to Energy Education. As a form of energy, heat is conserved, i.e., it cannot be created or destroyed. It can, however, be transferred from one place to another

  *STATE ONE PRACTICAL APPLICATION OF*

*I CONDUCTION*

Heat will transfer from a hot burner on the stove into a pot or pan. A metal spoon becomes hot from the boiling water inside the pot. Chocolate candy in your hand will eventually melt as heat is conducted from your hand to the chocolate. When ironing a skirt, the iron is hot and the heat is transferred to the skirt.

*RADIATION*

Today, to benefit humankind, radiation is used in medicine, academics, and industry, as well as for generating electricity. In addition, radiation has useful applications in such areas as agriculture, archaeology (carbon dating), space exploration, law enforcement, geology (including mining), and many others.

              Q5c

*Questions;- Explain the following processes in relation to the nitrogen cycle*

*i) Denitrification* is the process in which the nitrogen compounds makes its way back into the atmosphere by converting nitrate (NO3-) into gaseous nitrogen (N). This process of the nitrogen cycle is the final stage and occurs in the absence of oxygen.

*Ammonification*. When an organism excretes waste or dies, the nitrogen in its tissues is in the form of organic nitrogen (e.g. amino acids, DNA). Various fungi and prokaryotes then decompose the tissue and release inorganic nitrogen back into the ecosystem as ammonia in the process known as ammonification.

        *Leaching*

In this , microbes in the soil turn nitrogen gas (N2) into what is called volatile ammonia (NH3), so the fixation process is called volatilization. Leaching is where certain forms of nitrogen (such as nitrate, or NO3) becomes dissolved in water and leaks out of the soil, potentially polluting waterways.

   Two ways by which nitrogen is added

I) animal manure

ii sewage

  Ditrogen is removed from the soil

Leaching

Erosion

[27/11, 08:28] Eric: _*DISADVANTAGE OF FRICTION*_

_*(1)* It causes wear of machine parts_

_*(2)* It slows down motion._

_*(3)* It heats up moving parts of a machine and can lead to melting_

_*(4)* It reduces the efficiency of the machine by dissipating the energy of the machine as useless heat_

[27/11, 08:28] Eric: _*ADVANTAGE OF FRICTION*_

_*(1)* Enables one to open a screwed-topped bottle_

_*(2)*  It helps in the functioning of safety belts_

_*(3)* It keeps the feet from slipping during walking_

_*(4)* It makes motion of vehicles possible_

_*(5)* It makes sharpening of cutlass possible_

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GOOD LUCK