Concept Builder 1. Mr. Edmonds uses visuals and a song to reinforce how you find the volume of REGULAR solid objects to the tune of "Downtown". Some of the key vocabulary words include the following: length, width, height, volume, meters, and centimeters. This is a great resource to help students master this important skill. Middle School and High School students will enjoy this fun, catchy tune. (3:46)
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Concept Mastery Material: Matter is defined as anything that has mass and takes up space which means has volume. The Liter (L) is the SI unit for volume. Usually, small volumes of liquid are given in milliliters (mL). Remember that 1 L equals 1,000 mL. Any volume of liquid, from one tear drop to the entire Pacific Ocean, can be given in liters or milliliters.
Liquid Volume
In science, you will use a graduated cylinder to measure a liquid’s volume. Graduated cylinders are used to measure liquid volume because it is the instrument with the greatest accuracy. Liquids do not sit level in a container. Because of this, the surface of a liquid in any container is curved. This curve at the surface of a liquid is called a meniscus. Volume must be measured from the lowest point of the meniscus, as the following figure shows. Because the meniscus only curves slightly, water’s meniscus looks flat in a large-mouthed container. To find the volume of the object in the graduated cylinder you must take the reading at eye level as shown in the picture. Make sure you know what the scale divisions on the cylinder lines stand for. Some graduated cylinder marking lines stand for 2ml or even 5ml in the larger ones. In the example below the marking lines each represent 1ml.
Volume of an Irregularly Shaped Solid Object
To find the volume of a solid that does not have a regular shape requires a procedure called water displacement. When an object is added to the water in a graduated cylinder, the level of the water rises. This happens because the object pushes water out of the way and displaces it with its own volume. The volume of water displaced by the object is equal to the object’s volume. Because 1 mL is equal to 1 cm , you can give the volume of the water displaced by the object in cubic centimeters. If the object floats, take a thin pointed instrument and press the object down until it is fully covered by water and then take the reading. In the following figure you can see how the water is displaced by objects. If you take a reading of the water level before placing an object into it and then another afterward, the difference in the two readings will be the objects volume. If a measuring device is not available this technique can be used for regular shaped object as wall.
In the first example below, the water level rose from 19ml to 29ml when the chalk stick was placed in the graduated cylinder this shows the chalk stick displaced 10ml of water so the objects volume is 10ml. This number was found by subtracting the starting volume of water (19ml) from the final volume reading (29ml). Now it is your turn to find the volume of the example with the ring. The answer will be located in the notes at the end of this tutorial.1
Click on the blue finding volume link below to watch a video showing a full demonstration of these techniques.
Notes:
1 The volume of the ring is 4ml. The ending reading of 68ml minus the starting reading of 64ml shows the ring displaced 4ml of water.
You are now ready to take the quiz to show your mastery of this concept! GOOD LUCK and please give a rating to this tutorial. Thankyou.
