Activity Industry Sector
Health Science and Medical Technology

## Guided Practice

### Activity Overview / Details

It is recommended that the ladder method is used to teach metric conversions. Attached is a modified powerpoint from the original from T. Trimpe- the original can be found on the Science Spot website (link below).  The Science Spot website has a number of additional resources for teaching the metric system.

The students can complete the notes on the attached metric conversion notes sheet. This also includes the practice problems for the guided practice and independent practice.
Lesson Directions

1. First tell students that we measure using three basic units- grams (g) for mass, liter (l) for liquids, and meters (m) for distance.
2. All seats in my classroom are numbered so there are even and odd seats.   it is a quick way to identify who will talk and who will listen when we are sharing information.
3. Pair and share and have the odd students tell their lab partner the three basic measuring units without looking at their notes.  The even students should be listening.
4. Instruct the even students to say “ I heard you say the ___________, _________, and ___________ are the basic units of metric measurement.  Have the even student fill in the blanks.  Then have them tell the odd numbers students what each is used to measure.
5. During this time, the teacher walks around the room and listens to the student's responses to check that they are providing the correct information.
6. Tell students that we use different prefixes for the amount of metric measurement and explain that each one of these will be in a box on the ladder.   You can use a pneumonic device like “ Kids Have Dropped OVER Dead Converting Metrics Unfortunately” to help them remember the abbreviations (kilo, hecto, deka, basic unit (m, g, L) ; deci, centi,  milli,  micro). Make sure you have the students write down the abreviations on their copy of the ladder.  I tell them that we won't drop over dead because these problems can be solved in 3 easy steps that we are going to learn.
7. The ladder method gives students a visual that relates each unit to a change of 10. I explain how the metric system is based on the number 10, and use the PowerPoint to show how each unit either goes up or down by 10.  Walk them through each one, explaining as you go that each step up the ladder is like going up by ten.
8. Ask the even numbered students to tell the odd numbered students how much each step of the ladder is equal to.  The answer should be ten.
9. In the beginning, the lesson is focused on counting the number of "jumps" it takes to move from one metric unit to another. The "jumps" determine the number of times the decimal is moved and in which direction.
10. I remind students to count the number of jumps it would take to move from one unit to another, such as moving from meters to millimeters, rather than counting the number of boxes. To convert from meters to millimeters, it would take 3 jumps to the right which would mean the decimal would need to move 3 jumps to the right.
11. Ask the odd numbered student  to tell their partner how many jumps it would take to move from a 1 kg to a g.
12. Ask the even numbered student to tell their partner how many places they would move the decimal point and in which direction.
13. I ask the students to review the 3 steps to solving conversion problems-  I ask them in choral response what they are. 1 st – Determine your starting point. 2 nd – Count the “jumps” to your ending point. 3 rd – Move the decimal the same number of jumps in the same direction.
14. Then I have  them take turns sharing and doing a 30 second summary step to their partner, odd student goes first.

15. The second to the last slide of the presentation has some practice problems. I do these problems with the students randomly calling on them to walk me through the problems. We do each problem step by step.  First they tell me what I am converting between, then how many jumps I need to take, and then in which direction to move the decimal.  The practice problems focus on liters and grams since that is what we primarily deal with in class.  During each problem I am randomly calling on a new student for each step, this allows me to check for understanding and quickly correct any misconceptions.
16. Students are then asked to work on the remaining problems (last slide) with their partner.  The students are instructed to take turns explaining how to solve the problem to each other for the first 5 problems and then complete the remaining 5 on their own.  Make sure to tell the students which partner goes first (you pick).  During this time I am walking around the room and listening to responses.
17. After the students have finished the practice problems, I randomly (popsicle sticks) call on them and review the answers- the students follow along and check their answers.

As they learn the process and understand the value of the metric prefixes, I introduce using multiplication and division by 10, 100, and 1000 to accomplish the same conversion.ish the same conversion.