Science 10 Assignment 2.1 (27 marks)
1. Define the term “thermodynamics” (1 mark)
It is a branch of science that shows the connection between heat and energy.
2. State the first law of thermodynamics. (2 marks)
The first law of thermodynamics shows a notion of energy for a thermodynamic
system.
3. What is the distinction between work and heat ? (1 mark)
Heat and work are both forms of energy, heat is a quantity of heat that flows from a
hot object to a cold object (eg; human bodies). Work is when for example a forklift is
lifting a heavy object, energy is transferred from the forklift to the load its lifting.
4. Identify whether each of the following is best explained by the first or second
law of thermodynamics. (3 marks)
a) A bouncing ball eventually comes to rest on the floor.
Second law
b) A metal spoon eventually becomes hot when placed in a pot of boiling
water.
First law
c) Energy cannot be created or destroyed
First Law
5. What is the difference between a heat engine and a heat pump ? Give and
example of each. (2 marks)
Heat pump uses work energy to be able to heat the water
Engines use work energy to produce heat to be able to create heat to warm
the inside of the car.
6. What is a perpetual motion machine ? (1 mark)
It is a form of motion that doesn’t require an external source of energy
7. State the second law of thermodynamics. (1 mark)
It is when a physical system spontaneously works its way towards its own
state of thermodynamic equilibrium.
8. Explain why Hero’s steam engine was used only for entertainment purposes.
(1 mark)
it was only used for entertainment because it wasn’t big enough or strong enough to
power anything
9. What events in the 1600s led to the invention of technologies that used
steam energy ? (2 marks)
It made it so that you could power factories to produce goods faster, it also led to the
steam engine so that you could power locomotives and ships and automobiles.
10. What two scientific discoveries in the 1600s led inventors to use steam to
drive an engine ? (2 marks)
In 1643 Evangelista invented the barometer to show that air has weight and
pressure.
In 1654 Otto Von Guericke invented the air pump, it created a vacuum. He used the
atmospheric pressure to push the piston down the create the pressure and the
ability to do work.
11. Why was the steam engine developed before internal combustion engines
that used coal gas or gasoline ? (1 mark)
A steam engine was developed before the combustion engine because you could rin
the steam engine off of water. Back in the 1600’s people didn’t have the ability to
extract the coal and gas out of the ground and separate it from the sand and dirt.
12. Why did Watt consider the Newcomen steam engine highly inefficient ? ( 1
mark)
He thought they were inefficient because when they used steam engines to pump
the water out of the mines cold water would be flowing through the extraction pipe
which cooled off the engine. Every time the cold water shot through the extraction
pipe steam was lost.
13. What was one change that Watt made to the design of the steam engine to
make it more efficient ? (1 mark)
Watt installed a second chamber on all his engines which was a condensation
chamber which the water flowed through. That way the first chamber could create
the work energy to be able to move the water without losing energy.
14. List two advantages and two disadvantages of the steam engine. ( 4 marks)
15. What innovation did Daimler introduce to the internal combustion engine
and why was it an improvement ? (2 marks)
16. In the internal combustion four stroke engine, what is the purpose of the intake
valve and the exhaust valve ? (2 marks)