Page 130 - Microsoft Word - LessonPlan-Overview.doc
P. 130
Unit 4: Energy (Part 1) Page 9
It takes about 66 Newtons to lift a Work is not that hard...it’s force
15 pound bowling ball and it would that can be difficult. Imagine
take a 250 pound linebacker about getting up a ten step flight of stairs
1000 Newtons to lift himself up the without a set of stairs. Your legs
stairs! So, if you lifted an apple don’t have the strength/force for
one meter (about 3 feet) into the you to jump up, you’d have to
air you would have exerted one climb up or find a ladder or a rope.
Joule of energy to do it. The stairs allow you to, slowly but
surely, lift yourself from the
The calorie is generally used to talk bottom to the top.
about heat energy and you may be
a bit more familiar with it due to Now imagine
food and exercise. A calorie is the you are riding
amount of energy it takes to heat your bike and
one gram of water one degree a friend of
Celsius. Four Joules are about one yours is
calorie. (Note - when most people running beside
talk about calories, they refer to you. Who’s got
Calories with a capital C (AKA the tougher
'kCal' or kilo-calories) which is job? Your friend right? You could
1,000 calories. For example, if a go for many miles on your bike but
soda has 160 Calories, it has your friend will tire out after only a
160,000 calories!) few miles. The bike is easier
(requires less force) to do as much
Who Cares?! work as the runner has to do.
We spent a lot of time on this Now here’s an important point, you
strange concept called work. Work and your friend do about the same
happens when something moves a amount of work. You also do the
distance against a force. same amount of work when you go
Swell...who cares?! Well, believe it up the stairs verses climbing up
or not, this is truly one of the most the rope. The work is the same,
useful concepts in physics. I’m but the force needed to make it
willing to bet you spend a lot of happen is much different. Don’t
your time moving things a distance worry if that doesn’t make sense
now. As we move forward, it will
against a force.
become clearer.
Do you ever climb stairs, walk, ride
a bicycle, or lift a fork to your Highlights for Energy
mouth to eat? Of course you do.
Each one of those things requires Energy is the ability to do work.
you to move something a distance
against a force. You’re using Work is moving something against
energy and you’re doing work. a force over a distance.
© 2010 Supercharged Science www.ScienceLearningSpace.com
130
