Download Obj 4 Stations - O. Henry Science

Station 5: Simple Machines
Read This
Work is the measure of the force applied to move an object. In science, work only
occurs if a force is applied that causes an object to move.
Simple Machines make work easier by reducing the amount of effort force
needed to move an object, changing the direction of the effort force, or
increasing the distance over which the effort force is applied. There are six simple
machines: lever, pulley, wheel and axle, wedge, screw, and inclined plane.
Do This
Part 1 – Inclined Plane
1. Measure the height of the stack of books. Record this height on your student page.
2. Hook the spring scale through the weight and carefully lift the weight straight off the table so
that the bottom of the weight is even with the top of the stack of books.
3. Record the force from the spring scale on your student page. This is the amount of force
needed to lift the weight straight off the table.
4. Set up the ramp.
5. Use the spring scale to carefully pull the weight up the ramp. Once again the bottom of the
weight should be even with the top of the stack of books.
6. Record the force from the spring scale on your student page. This is the amount of force
needed to move the weight to the same height using a ramp.
7. Answer the analysis questions.
Part 2 – Pulley
8. Again, hook the spring scale through the weight and carefully lift the weight straight off the
table so that the bottom of the weight is even with the top of the stack of books. Record the
force required.
9. Remove the spring scale from the weight and hook it to the end of the pulley string.
10. Carefully pull the spring scale to lift the weight using the pulley. Record the amount of force
required to lift the weight using one pulley.
11. Reset the pulley so that both are being used. Use the spring scale to lift the weight to the top of
the stack of books. Record the force needed.
12. Answer the analysis questions.
PULLEY
Station 6: Potential and Kinetic Energy
Read This
Potential energy is stored energy or energy related to the position of an object.
Kinetic energy is energy of motion. Moving objects have potential and kinetic
energy. As an object falls it is losing potential energy and gaining kinetic energy
as it speeds up. Look at the picture below:
At point C the cannonball is at its highest point and slowest speed.
Point C is the point of greatest POTENTIAL ENERGY.
At point E the cannonball is very close to the ground, but has
accelerated to a high speed. Point E is a point of very high KINETIC
ENERGY.
From point A to point C the potential energy of the
cannonball is INCREASING. What is happening to the
potential energy between points C and E?
Between what points is the kinetic energy increasing?
Between what points is the kinetic energy decreasing?
Do This
1. Place the marble in the track and let it go.
2. Repeat the run of the marble and pay attention to the marked points on the track.
3. Describe the level of potential and kinetic energy at each of the labeled points on the track.
Station 7: Energy Transformations
Read This
Energy comes in many forms including mechanical, chemical, nuclear, heat, and electromagnetic. Some
forms of energy can be converted to other forms.
For example, solar panels are used to capture light energy from the sun and convert it to electricity.
Green plants undergo photosynthesis to convert light energy into chemical energy in the form of food.
The mechanical energy of a waterfall can be converted to electromagnetic energy in a generator.
Generators convert other types of mechanical energy into electromagnetic energy.
Many times it takes a whole series of energy conversions to do a certain job. For example, just to get the
energy to make a piece of toast, there are several energy conversions involved.
Chemical energy stored in coal is released as heat and light energy when the coal is burned. The heat
energy is used to produce steam and is changed into mechanical energy in a generator. The generator
converts mechanical energy into electric energy that travels through power lines into your home. When
you use your toaster, that electric energy is again changed into heat energy.
Have you ever touched a lightbulb when it was on? Or tried to change it when it burnt out
after being on? What you have discovered is the conversion process of energy? When you
turn on a light, not all of the electricity is converted to light energy. Some of the energy is converted to
heat. Although some energy is changed to heat and does not help do the work, the energy is not lost. In
fact, energy is never lost; it is only converted from one form to another. This is stated in the law of
conservation of energy, energy cannot be created or destroyed.
Do This
1. Identify the type of energy conversion presented in each example.
2. Record your answers in the table on your paper.
Station 8: Mass and Weight
Read This
Mass and weight are two common measures of matter. Mass is the amount of matter in an object and
is measured in grams. What piece of lab equipment do you use to measure mass?
Weight is a measure of the force of gravity on an object’s mass. This means that weight changes based
on the amount of gravity and object is experiencing. For example, a person that weighs 100 lbs on Earth
will weigh less on the moon because there is less gravity. That person’s mass will not change when they
are on the moon. Americans typically refer to weight in pounds, but in science we measure weight in
Newtons, the standard unit of force.
Do This
1. Find the mass of the 3 objects using the triple beam balance.
2. Record the masses on your student page.
3. Use the spring scale to measure the weight (force) of each of the objects. Record the weight in
your table.
4. Calculate the weight of the objects using the formula WEIGHT = MASS x GRAVITY
The gravitational constant on earth is 9.8 m/s2
5. Record the calculated weights.
6. Use the table of gravitational constants to find the weight of a 500g object on Mercury, Earth,
and Jupiter.
Acceleration Due to Gravity Comparison
Body
Mass [kg] Radius [m]
Sun
1.99 x 1030 6.96 x 108
Acceleration Due
g / g-Earth
to Gravity, "g" [m/s²]
274.13
27.95
Mercury 3.18 x 1023 2.43 x 106
3.59
0.37
Venus 4.88 x 1024 6.06 x 106
8.87
0.90
Earth
5.98 x 1024 6.38 x 106
9.81
1.00
Moon
7.36 x 1022 1.74 x 106
1.62
0.17
Mars
6.42 x 10
3.77
0.38
Jupiter 1.90 x 1027 6.99 x 107
25.95
2.65
Saturn 5.68 x 1026 5.85 x 107
11.08
1.13
Uranus 8.68 x 1025 2.33 x 107
10.67
1.09
Neptune 1.03 x 1026 2.21 x 107
14.07
1.43
0.42
0.04
Pluto
23
3.37 x 10
6
1.40 x 1022 1.50 x 106