Can somebody help me with these Science Questions?

Question

#1-During a race, how does a marathon runner transfrom chemical energy into heat?

#2-How does an electric toaster transform electrical energy into heat?

#3-How does teh sun transform nuclear energy into heat?

#4-How can a battery transform chemical energy into heat?

#5-How does a curling iron transform electrical energy into heat?

#6-How can a nuclear energy station heat the water in a nearby lake?

Also can you help me with these too?

a)Name two ways heat is produced by a peprson pedaling a bicycle.

b)Name two ways heat can be produced by a bolt of lightning.

c)Name two ways that the sun can heat a home.

Can you when you answer name the thing your answering by the letter or number?

Thanks

Answer 1

#1 - (I am not too sure of this) The chemical energy obtained by consuming food is present in the form of glucose in the blood. Cells in the body (specifically the mitochondrion) oxidizes this glucose using oxygen and in the process releases water and a small amount of heat. During a race, the rate of oxidization is faster and hence more heat is liberated...

#2 - Inside an electric toaster, there is a wire (coil) which has a very high resistance. When electricity flows through the high resistance wire, it generates heat due to power dissipation (VoltagexCurrent=Power). Thus, electrical energy is transformed into heat

#3 - Nuclear fusion in the sun basically causes a decrease in matter when two atoms of hydrogen combine to release one atom of helium. Along with this decrease in mass, there is also some energy released since helium is more stable than hydrogen. Thus the mass shows up as energy using Einstein's equation E=mc^2, and added to that is the energy due to the stability difference... This shows up as heat and light

#4 - A battery has electrons flowing from one of its terminals to the other. Basically, its a battery because it generates electricity. Next, using the same logic as the toaster, we can say that electricity can generate heat. Other than that, the batter's chemical reactions may also generate heat, again due to the very nature of the reaction.

#5 - A curling iron, very much like a toaster, has wires (usually of the material - nichrome) which has a high resistance, and hence dissipates a lot of heat when electricity flows through it...

#6 - A nuclear energy station works in a similar manner as the sun, except it usually uses nuclear fission, rather than fusion. Now, the energy generated by the fission reaction is used to heat up water, which is then used to generate electricity (in much the same was as a steam engine uses heated water to move). Once the heated steam expands (or does work) which in turn may drive a turbine to generate electricity. The steam cools down, to hot water, which might heat up a lake...

a) The person can produce heat due to the friction between the tyre and the ground, due to the friction between the pedal and the chain driving the wheel, due to friction at the wheel's suspension point etc

b)A bolt of lightning can be thought of as a lot of electricity, and consequently, it can generate heat when it causes electricity to pass through anything with a lot of resistance (ex: When it strikes a lightning rod, it causes electricity to pass through the rod and hence heats up the rod). Also, one can say that lightning may split up molecules of chemicals in the sky and this reaction may in some cases lead to heat generation

c)The sun can heat a home directly by its heat (i.e. sunlight brings along with it some heat from the sun). Other than that, one can think of solar panels which may convert sunlight into electricity, which in turn can heat up things

Basically, the easiest thing to do would be to try and get electricity into the picture. Once you are able to convert a particular form of energy into electricity, you have a wide variety of gadgets around you which convert electricity to a lot of other forms of energy and hence your answers will come faster...

Hope that helps :)