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Basic Measurements: Length, Mass, Time, and Temperature

Learn how to measure length, mass, time, and temperature, and understand the SI system of measurement. Perform simple calculations based on measurements and know the standard units for different physical quantities.

christopherjackson
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Basic Measurements: Length, Mass, Time, and Temperature

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  1. At the end of this unit you should: 1. Be able to measure length, mass, time and temperature. 2. Be able to perform simple calculations based on measurements. 3. Understand that units of measurement follow the SI system. 4. Know the standard units for different physical quantities.

  2. area density error force length mass measurement metre stick opisometer physical quantity quantified SI units temperature thermometer time trundle wheel Vernier callipers volume

  3. LIGHTBULB QUESTION Measurements tell us how long, tall, heavy or far away something is. If you didn’t have any measuring equipment, you could measure things with your hands, forearms or feet.

  4. LIGHTBULB QUESTION Horses are still measured using hands. One hand is equal to four inches.

  5. Equipment: A ruler, a desk and your hand. Instructions: 1. In pairs, measure the length of your desk. 2. One person uses their hand and the other uses a ruler. 3. Write down your measurements. 4. Now swap around so that the person who used the ruler now uses their hand. Investigation 10.01.01: Basic measurements

  6. 1. Was there any difference between your measurements? • Yes, there should be a difference.

  7. 2. Compare your hand measurement with the others in the class. • Gather all the measurement data in the class and create a table to display your results. You can use the following headers as an example of how to create your table.

  8. 3. Which graph would you use to represent this data? A scatter plot graph would be the best graph to represent the data. E.g.:

  9. Physical Quantity: The scientific term for a measurable characteristic, for example length, time and temperature. Quantified: The scientific word for saying an object has been measured.

  10. (a) What is a physical quantity? Name five. • A physical quantity is the scientific term for a measurable characteristic, for example length, time, temperature, area and volume. • (b) Write sentences to quantify the following items: bread, water, cereal, toast. • 1. May I have one slice of bread, please? • 2. It is only €1 for a 1-litre bottle of water in the shop. • 3. I normally take two Weetabix in the morning. • 4. I couldn’t have more than two slices of toast in the morning.

  11. Measurement: Giving a numerical value to a physical quantity.

  12. (a) Define measurement and give two examples. • Giving a numerical value to a physical quantity, e.g. length, time, speed. • (b) Why were SI units created? Do you think they are a good idea? Why? • SI units were created to ensure that all measurements scientists used were of the same standard. It is a great idea as it means results can be easily replicated without needless discussion, and it makes international collaborations much easier. However, some countries have not adopted the SI system and instead use the imperial system.

  13. (c) Choose four SI units. Name them, name their units of measurement and list at least one alternative measurement for each of them.

  14. (d) Thinking back to John, Jack and Mary, which expression of their height is correct? • Expressing length in metres is correct.

  15. Investigation 10.01.02: Selecting appropriate measuring tools Equipment: Equipment: An opisometer, a trundle wheel, a ruler, a metre stick and a Vernier callipers.

  16. Investigation 10.01.02: Selecting appropriate measuring tools Instructions: Copy Table 10.01.02 into your lab copy. Write down what instrument you are going to use to measure each item and what units that instrument measures in. 3. Collect all items and measure them, noting the results in your lab copy. 4. Add two extra objects that are not on the list, what tool would be the best to measure them with, what units are they measured in?

  17. Investigation 10.01.02: Selecting appropriate measuring tools Results Table:

  18. 1. When considering which instruments to use, remember that the question asks you to choose ‘the best’ for measuring each object/distance. There are two factors we must consider: ‘ease of use’ and ‘error’. These might be considered good reasons not to use a 15 cm ruler to measure a long distance. Can you think of an item to measure in which two or more of the measuring tools mentioned in Table 10.01.02 might be appropriate? • A metre stick or a trundle wheel could be used to measure the length of a classroom.

  19. Error: How far off the correct value you are.

  20. Copy and complete Table 10.01.03. Change your chosen instrument from Investigation 10.01.02 if you feel another one could reduce the error in your measurement. Determine which instrument you think would have the highest error for the stated measurement.

  21. Copy and complete Table 10.01.03. Change your chosen instrument from Investigation 10.01.02 if you feel another one could reduce the error in your measurement. Determine which instrument you think would have the highest error for the stated measurement.

  22. Area: How much surface an object occupies. l × w (m2).

  23. Investigation 10.01.03: Measuring the area of your hand Equipment: Your hand, a pencil, some graph paper and a ruler. Instructions: Measure the size of one square on the graph paper using your ruler. (Maths copy squares are 1 cm2) Trace your hand on to a piece of graph paper. Count each of the squares inside the tracing of your hand.

  24. 1. Compare the area of your hand to the person beside you. Is it the same, bigger or smaller? E.g. Mary’s hand is smaller than Jack’s but bigger than Alice’s.

  25. 2. Create a table of the hand sizes in your class. The following headers could be used:

  26. Volume: How much space an object takes up. l × w x h (m3).

  27. Calculate the area of an item in your schoolbag. Measure the length and width of a textbook and multiply the figures to get the area. (b) Calculate the volume of an item in your schoolbag. Measure the length, width and height of the textbook and multiply the figures to get the volume.

  28. Investigation 10.01.04: Measuring the volume of an irregularly-shaped object Equipment: A graduated cylinder, an irregularly-shaped object, an overflow can.

  29. Investigation 10.01.04: Measuring the volume of an irregularly-shaped object Instructions: 1. Fill up an overflow can so that the water line is just below the spout of the can. 2. Place a graduated cylinder underneath the spout of the can. 3. Place your irregularly-shape object carefully into the overflow can. 4. Allow time for the water to settle (about thirty seconds to a minute). 5. Measure the volume of displaced water in the graduated cylinder.

  30. 1. Could this method be used to find the volume of a regularly-shaped object? Yes it could, but it is easier to just measure length by width by height.

  31. 2. Suggest one change you would have to make if your irregularly-shaped object did not fit into the overflow can. Get a bigger overflow can.

  32. Investigation 10.01.05: The diet cola challenge Equipment: A container filled with water, a can of regular cola, a can of diet cola, some masking tape.

  33. Investigation 10.01.05: The diet cola challenge Instructions: 1. Before you start the experiment, prepare cans by covering them in masking tape. 2. Fill a water trough with water. 3. Place cans of cola into the water, allow time to settle and note observations.

  34. 1. How do you know which can is diet and which can is regular? Explain your answer. The presence of sugar in the drink influences the density of the can, the diet coke, with no sugar will therefore float to the top.

  35. 2. Is this a fair test? Yes, as you are using the same volume of water in the trough and each can holds the same volume.

  36. 3. Does the amount of masking tape used change the density of the can? The masking tape may have had some impact on the density of each can, but since the same amount of tape should have been used on each can, it should not impact the fairness of the test.

  37. LIGHTBULB QUESTION It is useful for when we want to know if certain objects will float or sink in liquids, i.e. boats floating in water.

  38. LIGHTBULB QUESTION A digital thermometer provides instantaneous readings. It is accurate to one decimal place, unlike an alcohol thermometer.

  39. Investigation 10.01.06: How to measure objects using a thermometer Equipment: Five beakers containing: water from a cold tap, water from a hot tap, boiling water from a kettle, tea with milk, water from the fridge. Instructions: 1. Fill five separate beakers containing the liquids as listed. 2. Using a thermometer, measure the temperature of each liquid.

  40. 1. Using the results from your investigation, represent your data in a table and place them in order of hottest to coldest. Any table that lists the liquids in order of hottest to coldest is acceptable. E.g.:

  41. 2. What effect (if any) does milk have when added to boiling water from a kettle. It should lower the overall temperature of the mixture.

  42. 3. What precautions did you take to ensure your measurements were correct in each instance? Cleaning/drying thermometer between measurements; stirring before measuring; allowing the thermometer time to settle at the highest/lowest temperature reached.

  43. 4. Write one safety precaution you must take when performing this investigation. For example, wearing gloves, goggles, lab coat, etc.

  44. (a) What apparatus would you use to measure force? Spring balance. (b) Which two actions do you need to perform to calculate the density of an object? Calculate the mass and volume of the object. (c) Name two occasions when it would be useful to use a digital thermometer. When looking for minute differences in temperatures; where the temperature is too great that you risk melting the bulb of the thermometer; to get a more accurate temperature of an object.

  45. Copy and Complete In this unit I learned that the scientific term for a measurablecharacteristic is physical quantity. Examples of these include time, lengthand mass. In order to ensure everyone used the same units for measurements, the Système International d’Unités, or SI units, were developed. Length is measured in metres, the symbol of which is m. However, length can also be measured in smaller units called centimetres (cm), and also millimetres (mm). Timeis measured in seconds (s). Mass is measured in kilogramsand its symbol is kg. I also learned that area is how much flat space an object occupies. Also, volume is the amount of space an object takes up.

  46. 1. Define a physical quantity. A physical quantity is a scientific term for a measurable characteristic. 2. Define measurement. Measurement is giving a numerical value to a physical quantity.

  47. 3. Explain what ‘quantified’ means. • ‘Quantified’ is the scientific word for saying an object has been measured. • 4. Compose five sentences in which a physical quantity is quantified, for example: ‘He stole all of my lunch money.’ • The ruler is 30 cm long. • He bought 5 bars of chocolate in the shop. • There is 750 ml of water in that bottle. • The movie was 1 hour 45 minutes long. • She needed 250 g of flour, 3 eggs and 200 g of sugar to make the cake.

  48. 5. Copy and complete Table 10.01.04, selecting an appropriate measuring tool for each task.

  49. 5. Copy and complete Table 10.01.04, selecting an appropriate measuring tool for each task.

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