Take Home Physics Assignments
REMEMBER – USE GOGGLES IN EACH LAB
Take – Home Lab Rules:
- Use goggles in each lab. Remember, these kits contain parts that may be hazardous. Hazards include, but are not limited to, choking (especially dangerous to small children) and chemicals. Keep the kit out of the reach of small children.
- Answer the question at the beginning (it’s in bold - it is in every take home lab) of each lab. This should be the first thing in the lab report.
- If you are having trouble figuring out the lab look at your text or the internet for more background information.
- Draw a picture of your setup (Half of a sheet in size or larger).
- Don’t turn in a print out of the lab with answers to questions on the printout. You can print out the lab at home to help you do the lab – just don’t turn it in.
- Answer all questions in the lab, even if they are not in the “question” section. Include all tables and graphs. Graphs, tables, and drawings must be half of a sheet of paper in size or larger and labeled. The graph axes must be labeled.
- Include the “questions” along with the “answers”.
- Copying from someone else is cheating, even if you are working together. Use your own words!
- You are not excused from any take home lab because you are absent (even an excused absence). It is your responsibility to make up the lab when you return.
- I will not accept late take home labs unless you were absent from the time I announced the assignment to the time it is due.
- Read the discussion. It will help you with the lab.
- You may need to do some research to answer some questions. These questions will be worth more points.
- All empty small labeled zip lock bags must be returned to the kit once the bag's contents are used. There is a $5.00 charge for each bag that’s thrown away.
-Chapter 1 Intro
Lab 100
BUILDING YOUR BALANCE
How does a single beam balance work?
Discussion – You will be need a simple beam balance for many of the activities you will be doing at home this year. Remember how to make this balance. You will be making this balance several times this year. Remember this lab!!
Build your balance: (You will need a ruler, pencil or pen, and the 2 plastic cups in your kit).
1)Put a cup on each end of the ruler and attach with a piece of tape. Do not use too much tape as you will be taking the balance apart to use for different assignments.
2)Put a pencil or pen under the middle of the ruler. Adjust the balance point by moving the pencil or pen. When balanced the ruler may not be perfectly level, but by taping either cup you should be able to cause the balance to sway to either side. You should check this each time you use the balance.
3)The object you want to mass should be in one cup, then you can use the syringe to fill the other cup until you have a balance. Record the volume of water used.
4)Remember the density of water is 1.0 g/ml. That means 1 ml of water has a mass of 1.0 g. If it takes 17 ml to balance the sample, then the sample has a mass of 17 g.
Test your balance:
1)Find the mass of 4 pennies.
2)Draw a simple chart showing the mass of the 4 pennies.
Questions:
1)What was the percent difference between your mass using the balance and the accepted mass of the coin? (Use the internet to find the mass of the coin). Percent difference = (your value - accepted value)/accepted value).
2)What do you think is the biggest contributor to that difference?
3)Can you think of ways to make the balance more accurate?
4)What is the lightest mass you can find using your balance? Try different things (like the mass of 1 hair).
REMEMBER – USE GOGGLES IN EACH LAB
-Chapter 1 Intro
Lab 101THICKNESS OF PAPER
How thick is a sheet of paper?
Discussion - Scientists have measured objects that seem impossible to measure. We know the diameter of a proton and the speed of light. Each is impossible to measure directly, so scientists have found ways to measure things indirectly. It would be impossible to accurately measure the thickness of one sheet of paper with a ruler. In this lab, you will measure a stack of paper and mathematically determine the thickness of one sheet of paper.
This is similar to the calculations you will do later in chemistry. It is impossible to directly measure the mass of one carbon atom. We can, however, measure the mass of a large number of carbon atoms to figure out the mass of a single atom.
Procedure – Take a large number of papers (like 100) and measure the thickness of the stack (in cm).
Data – Number of sheets of paper ______
Thickness of the stack ______cm
Thickness of one sheet ______cm
Questions – 1) What are some sources of error in this lab?
2) How tall would a stack of 1,000,000 papers be (in cm and feet)?
3) How many sheets of paper would it take to stand as tall as a basketball rim (10 feet)?
4) What instrument can measure the thickness of one sheet of paper accurately? (May need the
Internet)?
-Chapter 2 Motion in One Dimension
Lab 1DISTANCE VERSUS TIME GRAPHS 1
Question:How does a distance versus time graph look for an object traveling at constant speed?
Discussion – In this lab you will be drawing distance versus time graphs for objects traveling at different constant speeds. The shape and trend of the graph will give you information about other distance versus time graphs you will see in physics.
Materials – Metric ruler with a groove down the middle, marble, stopwatch (you can download a stopwatch app to your cell phone or computer if you don’t have a stopwatch). Last choice: if you don't have a stopwatch or smart phone you can count using the old (but fairly reliable) "one-thousand ONE-one-thousand TWO-one-thousand THREE, etc. Practice this fist by looking at a second hand and making sure your count is accurate. So- it was just before I said the one in One thousand two so it was about 1.8 seconds. Get the idea???
Procedure – 1. Put removable marks or tape on a smooth surface (such as the floor or a table) at 0, 15, 30, 45, 60, and 75 cm.
2. Using your ruler set up a ramp to roll the marble down. Don’t put the bottom of the ramp right at the start line because you want to let the marble stop bouncing before you start timing it.
3. Place the ramp at a low angle (around 30°) and roll the marble from the top of the ramp. Start the watch when the marble crosses the start line and stop it when it gets to 15 cm. Repeat this 3X and average the results. You may want to put an object at the 15 cm mark that will make a loud sound when the marble hits it. This will help you stop the watch at the right time.
4. Repeat step 3, letting the marble roll to 30, 45, 60, and 75 cm. Make a chart and record all your data.
5. Repeat with the ramp at a higher angle of 45°.
6. Draw two line graphs (one for each angle) comparing distance (vertical axis) vs time (horizontal axis). Note: in this class time is usually on the horizontal axis, unless otherwise stated. Label the axes.
Questions – 1. What is the relationship between the slope of the graph and the velocity of the marble?
2. Calculate the slope of the two lines. What are the units of the slope? What does the slope represent?
3. What would the graph look like if the marble collided with a wall at 45 cm, and bounced off and rolled in the opposite direction at a slow speed then came to rest. Sketch this graph.
REMEMBER – USE GOGGLES IN EACH LAB
-Chapter 2 Motion in One Dimension
Lab 2DISTANCE VERSUS TIME GRAPHS 2
Question:How does a distance versus time graph look for an object that is accelerating?
Discussion – A distance versus time graph for an object traveling at a constant speed is a straight line and the slope of that line is the speed. An object that is accelerating has a changing speed or velocity – hence a changing slope. To figure out the instantaneous speed of an object during its acceleration, one must take the slope of the tangent line to the graph (see picture).
Materials – Marble, ruler, stopwatch (see Chapter 2, Lab 1), pie pan or other household item that will make a loud noise when hit by a marble.
Procedure – 1.Put removable marks or tape on a door frame or outside wall. Put the marks at 0.75 m, 1.25 m, 1.75 m, and
2.25 m.
2. Have someone help you drop a marble from each of these heights and into a pie pan (or something that will make a loud noise when the marble hits the pan. This will help you time the fall of the marble. Drop the ball from each of these marks three times and average the results.
3. Create a chart showing the time it took for the marble to fall for each distance for each trial.
4. Create a line graph with distance on the vertical axis and time on the horizontal axis. Draw a smooth curve through the points (don’t draw a straight line from point to point – see the picture above). Label the axes of the graph.
Questions – 1. What is the shape of your graph? What would the shape be if the object were slowing down instead of speeding up? What would the graph look like if the acceleration was zero?
2. Choose a place near the beginning of the graph and draw a tangent line. Choose a point near the end of the graph and draw another tangent line. What can you say about the speed of the object as it is dropped from greater heights?
3. When the marble was falling 2.25 m, did it take longer to fall the first half of the distance or the second half? Explain how you figured this out.
4. Look at a roller coaster on the internet. Draw a section of track (include at least 2 hills). Underneath your drawing draw a line graph showing distance versus time. Don’t worry about exact distances – just estimate them. Don’t forget to label the axes.
REMEMBER – USE GOGGLES IN EACH LAB
-Chapter 2 Motion in One Dimension
Lab 3AVERAGE SPEED
Question:What can you tell about an object’s motion by looking at its distance versus time graph?
Discussion – In this lab, you will investigate average speed. You will be dropping coffee filters from different heights and measuring the time it takes for them to hit the ground. Average speed is defined as the change in position over a certain segment of time. How quickly something moves a certain distance is the layman’s definition. The equation for average speed is: Average speed = change in position / change in time
If an object travels 5 meters in 2 seconds, it has an average speed of 2.5 m/s. Remember, this is just an average. This doesn’t mean that the object started out of finished at this speed. For example, if you drove 80 mi/hr for an hour, stopped and rested for an hour, then traveled 80 mi/hr for another hour, your average speed was 53 mi/hr even though you may not have traveled 53 mi/hr for more than a few seconds.
Materials – 3 coffee filters, ruler, stopwatch (see Chapter 2, Lab 1)
Procedure – 1. Put removable marks or tape on a door frame or outside wall. Put the marks at 60, 90, 120, 150, and 180 cm.
2. Have someone help you with dropping or timing the fall of the coffee filters (3 stacked together). Drop the coffee filters from each of the marks three times into a pie pan or something similar (loud) and average the results. Drop them like an upside down parachute (opening facing up). Come up with a method for coordinating the drop and starting the watch.
3. Record time and distance for each trial in a chart. Include average time and average speed.
4. Plot a line graph showing distance versus time (time is on the horizontal axis). Use cm and seconds. Label the axes.
5. Plot another graph reversing the axes of time and distance (time is on the vertical axis – note that this is rare.
Questions – 1. For which of the following would the relationship between average speed and final speed that you have learned in this lab be valid?
a. An airplane accelerates constantly on the runway before it takes off.
b. A car drives from Los Angeles to Las Vegas.
c. A water balloon falls from a second story window.
2. According to your graph, what would the speed be if you dropped the marble from 3 m?
3. Why were you instructed to put a pie plate or other loud object for the marble to fall into? (How does sound help?).
-Chapter 2 Motion in One Dimension
Lab 4 FINAL SPEED
Question:How can you use what you know about average velocity to determine the final velocity of an object starting at rest and accelerating constantly?
Discussion – In a previous lab, you learned how to calculate the average speed of an object. The average speed is useful if you’re driving and want to know how long your trip will take. Other times it’s not useful, like if you want to know your top speed during a drag race or the speed at the bottom of a roller coaster drop. In both cases you want to know your final speed.
When you average two numbers together, the average is halfway between them. If the first number is zero, then the second number must be twice as large as the average. For 0 and 10, the average is 5 and 10 is double 5.
So, to convert an average speed to a final speed for an object starting at rest and accelerating at aconstant rate, all you have to do is double the average speed.
Materials – Marble, ruler, stopwatch (see Chapter 2, Lab 1), and pie pan or something else to create noise
Discussion – 1. Put removable marks or tape on a door frame or outside wall at 1, 1.5, and 2 m.
2. Have someone help you drop a marble from each of these heights in a pie pan three times and average the results.
3. Record all of your measurements (distance, time) including the average time, average speed, and final speed.
4. Create a line graph with final speed on the x-axis and distance on the y-axis. Leave room for the y-axis to go to 3 m.
Questions – 1. Answer question 1 (Lab 3 above) for the relationship between average speed and final speed.
2. According to your graph, what would the speed be if you dropped the marble from 3 m?
3. Why are you instructed to put a pie plate for the marble to fall into?
REMEMBER – USE GOGGLES IN EACH LAB
-Chapter 2 Motion in One Dimension
Lab 5 ACCELERATION OF GRAVITY
Question: How can you use the average speed of an object starting from rest and accelerating constantly to determine its acceleration?
Discussion – In this lab, you will calculate the acceleration of gravity by timing a marble as it falls. The key is realizing the marble is starting with a velocity of 0 (vi = 0) and is accelerating constantly to a certain final velocity. The average of these two numbers is what is calculated by taking the distance traveled by the fall time. Because you know the average velocity and the starting velocity, you can calculate the final velocity (See Ch 2, Lab 4). From the final velocity and the time, you can calculate the acceleration. For an object starting at rest and accelerating constantly:
Vavg = (Vi + Vf)/2 [if Vi = 0, then Vf = 2 Vavg]
If possible have a friend time the dropped rock, but you can do this alone. That's why you have something to make noise when the rock hits the ground. You don't need to be looking at the rock to know when it hits the ground.
Materials: Marble, ruler, timer (see Chapter 2, Lab 1).
Procedure:
1. Make a temporary marks or tape on a wall 2 meters high. (About 79 inches high).
2. Put something on the ground to make a loud noise when the rock hits it. (A pie pan works well).
3. Drop the rock 3 times and record the time it takes 3 times. Try to do the best you can at getting a decent time. You need to estimate the time to the nearest tenth of a second. Record the times on the chart below.
4. Calculate the average time from the 3 times you recorded. (Yon have recorded 3 times. Get the average time).
5. Calculate the average velocity. (You already know the displacement (2 meters) and time, RIGHT???)
6.Calculate the final velocity of the rock just before it hits the ground. (HINT: final velocity = 2 X average velocity).
7. Calculate the acceleration of the rock. (HINT: acceleration = final velocity divided by time).
8. REPEAT FROM A DIFFERENT HEIGHT. DON'T GO BELOW 1 METER (39.4 INCHES).
Make a chart with the following headings: