Week 5 Gravity
Task 1 Types of Friction  Animation and explanation


Task 2 Watch this video and animation of the launch and landing of the Mars Exploration Rover
Spirit, MERA (Mars Exploration Rover  A), is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity (MERB), landed on the other side of the planet. Its name was chosen through a NASAsponsored student essay competition. The rover became stuck in late 2009, and its last communication with Earth was sent on March 22, 2010.


Task 3 Gravity  7.3
Page 264 Comparing mass and weight
Read this section and write the definition of mass and weight.
Record the units of measurement.
Page 264 Comparing mass and weight
Read this section and write the definition of mass and weight.
Record the units of measurement.
What is the relationship between mass, and weight force?
Analysing data.
Look at your results and find the relationship between the mass of an object and its weight force.
Hints
Hints
 Convert the masses to kg.
 Is there a mathematical operation that you can find?
 Is there a number that you can multiply the mass by to find the weight force in newtons?
 What is this number?
 Is it the same number every time? Bear in mind the level of accuracy of our measurements.
 Have you come across this number and its units before in this course?
Task 4 Measuring Weight Force
The balances drawn below all measure weight force.
1. Identify the number of one of these balances that you have used in class. Write its name in your book and use pencil and a ruler to draw it.
2. Note beneath it the common features of this type of balance.
1. Identify the number of one of these balances that you have used in class. Write its name in your book and use pencil and a ruler to draw it.
2. Note beneath it the common features of this type of balance.
4. Click on the image above to visit the website.
5. Scroll to the drawings of EqualArm Beam balances.
These balances measure mass.
6. Identify the number of one of these balances that you have used in class.
Write its name in your book and use pencil and a ruler to draw it.
7. Note beneath it the common features of all of these balances.
5. Scroll to the drawings of EqualArm Beam balances.
These balances measure mass.
6. Identify the number of one of these balances that you have used in class.
Write its name in your book and use pencil and a ruler to draw it.
7. Note beneath it the common features of all of these balances.
Task 5 Reading and NoteTaking
Read Gravity pages 263 to 264
Write the heading and today's date
Turn to page 269 and answer questions 1 to 6
Write the heading and today's date
Turn to page 269 and answer questions 1 to 6
Task 6 Investigation  Down with Parachutes
Refer to the Investigation test
Planning
Conducting  in the laboratory
Analysing the DATA and avoiding "group think"
Planning
 Write the Purpose
 State the independent and the dependent variables for this investigation.
 Suggest an hypothesis for this investigation.
 List three variables should be controlled. Controlled variables are factors that could affect the dependent variable so they must be "kept the same" or controlled during the investigation.
 Write the heading Procedure. List the steps that were followed.
 Write the heading Results.
 Draw up a table to receive the results of three trials and the averages.
Conducting  in the laboratory
 During class set up and conduct the experiment.
 Record results
Analysing the DATA and avoiding "group think"
 Construct a graph of the data from the Results table below. Describe the relationship from your results. Describe the relationship in the results below. How do they differ?
 Students had their own ideas of what the results should have been and so tried to match their results to their hypothesis. This is not science. Science involves constructing an hypothesis, making observations, collecting data and making inferences from the data; not the other way around.
 Imagine if Galileo had "fudged" the results of his cannonball drop!
Evaluating the Investigation.
There were a few flaws in the scientific method of the investigation.
Discuss the flaws in terms of;
Now that you have learned about ACCURACY try rounding the averages that you calculated. WHat is the realtiionship now?
There were a few flaws in the scientific method of the investigation.
Discuss the flaws in terms of;
 the accuracy of the measurements
 How accurate was your timimg? Think about the reaction time to stop the watch.
 How accurate was your timimg? Think about the reaction time to stop the watch.
 the reliability of the data
 Did you get the same result each trial? Should you eliminate very different results?
 Did you get the same result each trial? Should you eliminate very different results?
 the validity of the experiment.
 Was the height of the drop sufficient?
 Discuss how well the variables, other than the independent variable were controlled.
 Was the height of the drop sufficient?
Now that you have learned about ACCURACY try rounding the averages that you calculated. WHat is the realtiionship now?
Do different things fall faster? Visit the ABC website and watch Do different things fall faster? http://splash.abc.net.au/media?id=30393

Dr Cox discusses the ideas of Newton and Einstein. If it confuses you then you would be feeling how someone living in the time of Newton felt when he started talking about objects all being affected by an invisible "noncontact" force that we now call gravity. It is the thinkers and gatherers of data that help to expand the minds of others.